Dissertations / Theses on the topic 'Dendroecology'

Submitted by William Justo Figueiro (williamjf) on 2015-08-27T19:56:06Z No. of bitstreams: 1 30e.pdf: 524095 bytes, checksum: 83725900326890551c03ab7cc7a41525 (MD5)
Made available in DSpace on 2015-08-27T19:56:06Z (GMT). No. of bitstreams: 1 30e.pdf: 524095 bytes, checksum: 83725900326890551c03ab7cc7a41525 (MD5) Previous issue date: 2011
FUNDEPE - Fundação Universitária para Desenvolvimento do Ensino e da Pesquisa
Petrobras - Petróleo Brasileiro S. A.
Hovenia dulcis Thunberg (Rhamnaceae) é uma espécie arbórea de origem asiática, comumente encontrada como invasora em formações florestais do sul do Brasil, onde compete com espécies arbóreas nativas em áreas de sucessão inicial e em clareiras no interior de florestas. Esta espécie, conhecida popularmente como uva-do-japão, perde completamente as folhas no período invernal, indicando um padrão fenológico estacional que estaria associado à formação de anéis de crescimento no lenho. Essas estruturas anatômicas marcam ciclos sazonais de atividade do câmbio vascular, fornecendo registros anuais da idade e do crescimento das plantas. Dessa forma, a existência de anéis de crescimento nesta espécie permitiria desenvolver estudos dendroecológicos, relevantes ao entendimento e manejo do seu processo de invasão. Neste estudo investigamos padrões de crescimento de H. dulcis através de séries temporais de largura de anéis de crescimento e suas relações com o clima regional. O estudo foi realizado em florestas ciliares de três arroios da bacia hidrográfica do rio dos Sinos, RS (29˚40”30’S; 50˚70”20’W), em cotas de 64 a 274m de altitude. Foram coletadas amostras de secções transversais do tronco de 49 indivíduos, com auxílio de um trado de incremento. As amostras foram preparadas datadas e medidas, gerando séries temporais de crescimento que foram submetidas a análises de correlação, regressão e ordenação para avaliar padrões de crescimento entre árvores e relações com séries históricas de temperatura atmosférica e precipitação. Os resultados demonstram que o crescimento de H. dulcis é sensível ao clima e apontam os principais fatores de influencias no crescimento. Destacamos a convergência no crescimento das árvores independente do seu local dentro da área de estudo. O sincronismo de crescimento expresso na cronologia apresentou sinais climáticos regionais atuando sobre a população. A série de crescimento regional média foi positivamente relacionada com a precipitação durante a primavera e o verão atual e temperatura de outono anterior. Isso significa que o crescimento de H. dulcis é sensível à baixa disponibilidade de água durante o período vegetativo e temperatura fria no outono restringe a duração de atividade de crescimento, reduzindo o crescimento na próxima temporada. Através do perfil de crescimento das árvores, reconhecemos árvores de crescimento rápido como sendo as que apresentam melhor o sinal comum de crescimento da população e mais sensíveis ao sinal regional. Identificamos também os indivíduos velhos, pequenos e de crescimento lento como representantes ruins do crescimento comum, pois estes são influenciados principalmente por fatores de micro sítio. Assim a datação precisa da idade dos indivíduos merece grande destaque, pois sugerem que medidas de diâmetro não são bons descritores de idade, não sendo esta medida adequada para estudos ecológicos que necessitem de estimativa de idade.
Hovenia dulcis Thunberg (Rhamnaceae) is a tree species from Asia invading forest formations in south Brazil, where it competes with native tree species in early succession areas and forest canopy gaps. The blueberry-japan shades its leaves in winter, indicating a seasonal phenological behavior that would be related to the formation of wood growth rings. This anatomical xylem structures mark seasonal cambium activity cycles, thus informing about tree age and annual growth. The formation of annual rings in H. dulcis would allow the development of dendroecological studies, relevant to understand and manage its invasion process. This study investigates long-term growth patterns of H. dulcis and relationships to regional climate through tree-ring analyses. The study was carried our in three riparian forests within the Dos Sinos river catchment (29˚40”30’S; 50˚70”20’W), between 64 and 274 m asl. Fourty nine trees were cored with an increment borer to obtain transversal trunk wood samples for tree ring analysis. The wood cores were surfaced, measured, cross-dated and detrended to obtain a annual growth index time series per tree. Regional temperature and precipitation series were obtained from modeled grid data-set. Growth patterns among trees and relationships with climate were explored through ordination, correlation and regression analyses. Trees from different riparian forests showed a similar growth pattern, indicative of a regional growth signal. The regional signal strength variation among trees did not varied in function of age but was directly related to tree size controlling age, indicating fast growing trees were more sensitive to such regional signal, probably because slow growing trees would be more influenced to site factors. The regional mean growth series was positively related to precipitation during current spring and summer and to temperature of previous autumn. It means H. dulcis growth is sensitive to low water availability during the vegetation period and cold temperature in autumn restricts the duration of growth activity, reducing growth in the next season.

The ongoing drought in the US Southwest (SW) has led to particularly large and severe wildfires, tree die-off events, insect outbreaks, and increased forest stress levels. These disturbances underscore the vulnerabilities of SW dry conifer forests to climate change and past land-uses. Climate projections show a clear upward trend in regional temperatures, which will lead to accelerated heat-related stressors and disturbances in the coming decades. Already, more than 20% of the dry conifer forests of the SW have been severely impacted. This number is likely to grow, but we lack a clear picture of where, when, and to what degree other forest areas will be affected. Here, I apply dendroecological methods to evaluate patterns and processes that might determine greater or lesser vulnerability in dry conifer forests. Much of this work stems from critical concerns voiced by the Navajo Forestry Department (NFD). Long-term and representative data are necessary for the NFD, as they are responsible for closely managing over 250,000 hectares of forests and woodlands for the traditional products and ecosystem services that their forests provide for the Navajo people. The first study takes a multi-century perspective on changing fire regimes across Navajo forests, and places current forest structure and recent severe events in a long-term context. We found that surface fires were frequent across the landscape from at least the late-1500s until 1880. Navajo settlement of the area began to affect the fire regimes with added small fires in some areas beginning in 1700. By 1832, the rise of traditional pastoralist practices and transhumant migrations reduced fire activity in areas of greater use. Conditions changed following the establishment of the Navajo reservation in 1868, as livestock herds grew rapidly and initiated a near-synchronous and widespread collapse of fire regimes across the study area by 1880. The legacies of this change in land use are greater forest densities and higher fuel loads in some areas, raising the vulnerability of the forest to more severe fires. The second study assesses one of the most dramatic long-term consequences of recent high-severity fires in the SW, the rapid post-fire transition of dry conifer forest to oak-dominated shrubfields. To assess probable successional trajectories and interactions with climate change of recently converted forests, we reconstructed the age structures and fire regimes of some of the largest and oldest shrubfields in the Jemez Mountains of northern New Mexico. We found that shrubfields are a resilient configuration to drought and fire, historically burning at the same rates and under similar climate as dry conifer forests. Dense shrubfields pose a significant challenge to conifer recruitment from competition effects, with our sites persisting for over 100 years in the absence of burning and through periods of favorable climate to conifers. Given future warming favoring oak over pine, and projected trends in fire activity and high-severity fire behavior, we expect much more forest area to convert to shrubfield, especially in the absence of restoration efforts to reduce crown fire potential.Finally, we evaluate landscape-scale variability in tree growth response to regional climate across the Navajo forest. Projections of climate-induced forest decline often omit upper-elevation and mesic sites because they are not represented in regional tree-ring chronology networks. We found that these stands had much lower response to 20th century droughts than mid to lower elevation stands, and that targeted tree-ring sites are consistently more correlated with regional climate. However, as temperature-driven atmospheric moisture demand has remained above average since ~1997 in the study area, the upper-elevation trees are now nearly as responsive to regional climate as lower elevation xeric sites, probably due to increased moisture limitations. Recent warming has thus synchronized tree growth to an unprecedented extent across this large landscape and regionally.

Iberian Pinus uncinata tree-growth variability and its responses to climate are analyzed by means of dendrochonological methods from an individual- to a population-level scale across its distribution area in the Iberian Peninsula. This multiple approach provides new knowledge about the site-tree-climate interactions at an individual scale, and about the species performance at a population scale. Age-related changes in sapwood area were the main drivers of BAI in mountain P. uncinata forests. Thus, any potential climate-induced effect on BAI will be mainly driven by sapwood production, which is mediated by tree age and altitude. Because slow-growing high-elevation trees get older than fast-growing low-elevation trees, we expect differential age-mediated BAI responses along the altitudinal gradient. Climate plays a secondary role in controlling TRWi variability among coexisting trees even in these high-elevation environments. Actually, altitude plays a major role affecting P. uncinata TRWi responses to climate at the site and tree scales. This suggests that the altitude-mediated decrease in air temperatures is the major driver of TRWi at both the site and tree levels determining the maximum elevation of the tree growth form. These results also stress that both (a) a tree-scale approach to quantify growth-index responses to climate and (b) a detailed characterization of the potential drivers of those individual tree responses are requisites for applying an individual-based framework in dendroecology. Following a population-based approach, a weakness of the theoretically temperature-sensitive TRW proxy to capture recent warming trends is observed. Instead, summer drought is increasingly influencing TRW along the 20th century, which agrees with observations from Iberian mountain forests. Rising temperatures might have led to an increase in drought stress of Pyrenean and Iberian high-elevation forests as has been observed in other Mediterranean similar ecosystems. We may be attending how a physiological threshold in terms of optimal temperature for growth is surpassed, reinforcing the role of drought as a plausible growth-limiting factor of Iberian high-elevation forests during the last decades. The intricate topography and diverse climate of the Mediterranean Basin produce varied and often opposite trend signs in dendrochronological proxies like TRW or BAI even between neighbouring sites, during the last decades. In spite of this local complexity, our findings reveal a pattern acting at synoptic scales where tree growth across the Mediterranean Basin is limited by drought or low water availability during the growing season.
La variabilitat del creixement de Pinus uncinata (pi negre) a la Península Ibèrica i les seues respostes al clima són analitzats a aquesta tesi mitjançant mètodes dendrocronològics, des d’una escala individual a una escala poblacional. Aquesta aproximació múltiple proveeix nous coneixements sobre les interaccions lloc-arbre-clima a escala individual, i sobre el comportament de la espècie a escala poblacional. Canvis a l’àrea d’albeca relacionats amb la edat van ser els principals factors de control de l’increment d’àrea basal (BAI) a aquests boscos de muntanya durant el segle XX. Per tant, els efectes potencials del clima sobre el BAI seran controlats principalment per la producció d’albeca, la qual al seu torn està influïda per la edat de l’arbre i la altitud. A més, arbres de creixement lent solen trobar-se en major proporció a altituds més elevades que arbres de creixement ràpid; com els primers solen ser més longeus, esperem unes respostes del BAI influïdes per la edat. El clima juga un paper secundari en el control de la variabilitat dels índexs d’amplària d’anell (TRWi) entre arbres coexistents, inclòs tractant-se d’aquests ecosistemes d’alta muntanya. Al contrari, l’altitud juga un paper prominent pel que fa a les respostes dels TRWi de P. uncinata al clima a escales de lloc i d’arbre. Açò suggereix que el decreixement en altitud de la temperatura de l’aire és el principal factor de control dels TRWi a ambdues escales. Aquests resultats també manifesten que (a) una aproximació dendrocronològica a nivell d’arbre per a quantificar les respostes dels TRWi al clima i (b) una caracterització detallada dels factors de control potencials d’aquestes respostes individuals són requisits per a fer servir una estratègia individual en dendroecologia. Seguint una aproximació poblacional, s’observa un debilitament de l’amplària d’anell (TRW) a l’hora de reflectir les tendències recents d’increment de temperatura. Per contra, la sequera estival està influint al TRW cada vegada més al llarg del segle XX, lo qual concorda amb observacions a altres boscos ibèrics de muntanya. L’increment recent de temperatura pot haver produït un augment de l’estrès per sequera als boscos pirenaics i ibèrics d’alta muntanya, com s’ha observat en altres ecosistemes mediterranis similars. D’aquesta manera, és possible que s’estiga depassant un llindar fisiològic des del punt de vista de la temperatura optima de creixement, reforçant el paper de la sequera com a plausible factor limitant del creixement a boscos ibèrics d’alta muntanya durant les darreres dècades. La topografia intricada i el clima divers de la Conca Mediterrània produeixen tendències variades recents als proxies dendrocronològics com ara TRW o BAI, sovint de signe oposat fins i tot entre llocs propers. Malgrat aquesta complexitat local, els nostres resultats posen de relleu un patró a escala sinòptica on el creixement arbori al llarg de la Conca Mediterrània està limitat per sequera o per baixa disponibilitat hídrica durant el període de creixement.

Dry mixed conifer forests of southwestern North America are projected to be particularly vulnerable to ongoing persistent warm drought conditions, and related increases in wildfire frequency, size and severity, due in part to consequences of over a century of fire exclusion. Prescribed fire is applied actively in many landscapes to reduce hazardous fuel loads and continuity, restore forest community composition and structure, and increase tree resilience to drought stress. However, fire can also adversely affect tree growth by damaging cambial, root, and canopy tissues, leading to tradeoffs in the use of fire as a tool for forest resilience. Radial growth is an indicator of climatic and ecological stress and can thus provide a relative measure of resilience to stress and disturbances; but, the mechanisms driving tree resilience to prescribed fire and concurrent drought are poorly understood. Thinning effects of prescribed fire may increase tree resilience to drought by increasing water, light and nutrient availability and production of defense mechanisms. However, trends over the last century indicate warming temperatures are increasing tree sensitivity to fire by reducing post-fire growth (lower resilience) and increasing the likelihood of mortality. Trees can be resistant to fire exposure, and where growth changes occur they can be transient or persistent. We studied the interactions between tree- and stand-level fire effects on the growth responses of surviving Abies concolor, Pinus jefferyi, Pinus ponderosa, and Pseudotsuga menziesii over 24 years of variable climatic conditions in ten National Parks across the western and southwest United States. We used linear mixed effects models to identify mechanisms influencing resistance and resilience responses to fire and interannual climate, using climatic water deficit (CWD) as an index of climatic stress. Compared to pre-fire growth, trees exposed to fire increased growth during periods of greater water deficits. Tree growth responses were variable among and within species and size classes, but contingent on time-since-fire and the climate during the recovery period. Negative fire effects on tree resistance were generally transient, while climate and pre-existing stand conditions were persistent controls on tree resilience. These results suggest that antecedent and subsequent climate conditions modulate post-fire forest response. Consideration of climate variation could improve the strategic use of prescribed fire for tree resilience to drought, and a deeper understanding of factors contributing to prefire growth may elucidate the mechanisms driving post-fire growth responses.

Pinus palustris Miller (longleaf pine), in Virginia, is at the northernmost extent of its range. During presettlement times, this species occurred throughout the Piedmont and Coastal Plain of Virginia in pure and mixed stands, covering 607,000 hectares. This forest type has since been reduced to 81 hectares or 0.01% of its former range. Around 5,000 individual Pinus palustris remain on six sites in the coastal plains. Seacock Swamp and Everwoods are both sites known to have naturally regenerated Pinus palustris native to Virginia occurring in mixed-species stands. At both sites, I measured height and diameter of all Pinus palustris and cored individuals greater than 10 cm in diameter at breast height. A total of 71 trees were cored; the cores were crossdated and measured and crossdating was verified with the COFECHA program. A strong competition signal within the tree ring records at both sites signified the importance of stand dynamics on Pinus palustris in second-growth loblolly pine stands. These results are probably due to the mix of species within these stands and competition from loblolly pine as both the dominant understory and overstory species. Using Black and Abrams (2003) boundary line method, we calculated release and suppression events from the tree-ring record over the last century and found a very dynamic system. During the 1950s and 1960s, Seacock Swamp experienced major and moderate releases (23% moderate release and 18% major release in the 1950s and 33% moderate release and 49% major release in the 1960s) in response to a diameter-limit cut in 1953. Other major and moderate releases varied at both sites and may be attributed to different forest management practices that were in place throughout the last century however locating historical land use records to validate this was not possible at the present.
Master of Science

Identification of effects that climate teleconnections, such as El Nino-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), and North Atlantic Oscillation (NAO), have on wildfires is difficult because of short and incomplete records in many areas of the world. We developed the first multicentury wildfire chronologies for northeast China from fire-scarred trees. Regional wildfires occurred every 7years from the 1700s to 1947, after which fire suppression policies were implemented. Regional wildfires occurred predominately during drought years and were associated with positive phases of ENSO and PDO and negative NAO. Twentieth century meteorological records show that this contingent combination of +ENSO/+PDO/-NAO is linked to low humidity, low precipitation, and high temperature during or before late spring fire seasons. Climate and wildfires in northeast China may be predictable based on teleconnection phases, although future wildfires may be more severe due to effects of climate change and the legacy of fire suppression.

This research examines the influence of western dwarf mistletoe (Arceuthobium campylopodum) infection on the radial growth response of mature ponderosa pines (Pinus ponderosa) and its effects on dendroclimatic reconstructions. I hypothesize that trees with mistletoe have lower annual growth rates than uninfected trees, but exhibit higher mean sensitivities and stronger relationships between growth and climate variation. I tested these hypotheses using correlation and regression analyses to compare 100-year crossdated and standardized tree-ring chronologies from 26 infected and 29 uninfected trees. I compared both chronologies to climate variation as measured by changes in total precipitation, minimum, mean, and maximum temperature, and the Palmer Drought Severity Index (PDSI). Results show that trees infected with dwarf mistletoe have higher radial growth rates, exhibit greater sensitivity, and respond more strongly to climate variation. Both infected and uninfected chronologies are significantly correlated with the respective climate variables, but exhibit different patterns. The strongest correlations are between infected trees and PDSI for all months tested; significant correlations between uninfected trees and PDSI are limited to May through December lagged from the previous year. These results suggest mistletoe-infected trees are more sensitive to climatic factors than uninfected trees and may be useful for dendroclimatic analyses.

Doutoramento em Engenharia Florestal e dos Recursos Naturais / Instituto Superior de Agronomia. Universidade de Lisboa
Climate scenarios in the Mediterranean predict raising temperatures and more frequent and extreme drought. We focused on analysing the effect of drought on cork growth and chemical composition to evaluate if more frequent and severe forthcoming droughts will compromise the performance of cork as a sealant for wine bottles. A few species can produce cork in a significant proportion. We initiated this research on gathering the available information to put cork oak and its cork under this general panorama. We concluded that the cork from Quercus suber is presently the only raw-material with the characteristics necessary for production of solid cork products and focused our research on it. To study the response of cork-growth to drought and the effect of phellogen age we used a dendroecological methodology and a components resilience analysis, confirming that drought reduces growth and provided extra knowledge on this subject: cork oak is very tolerant and resilient to extreme droughts but more severe droughts correspond to higher decrease of growth and more trees affected although to greater recovery performance. Nevertheless, there are other factors involved in the response: site, tree and the age of the phellogen. Regarding chemical composition the research developed brings insights into the effect of drought on the proportion of its main components. Our results show that, in general, drought does not affect it, with some exceptions. Nevertheless, the variability associated to the tree is much more relevant than the effect of drought conditions and affects all the parameters analyzed. In practical terms, the potential increased occurrence of droughts arising from climatic changes will not compromise the performance of cork as a sealant for wine bottles but cork debarking rotations should be enlarged in order to have the necessary cork plank width, namely if the drought occurs in the first 2 years
N/A

Secondary growth responses of native and nonnative trees exposed to the same climatic conditions can elucidate sensitivities and thus adaptability to a particular region. A long-term mixed-species planting in the pine barrens of northern lower Michigan presented an opportunity to discriminate responses from species commonly planted in this region. Mean ring-width chronologies from living native Pinus resinosa Ait. and P. strobus L. and nonnative P. sylvestris L. and Picea abies (L.) Karst. at this plantation were generated, standardized, and analyzed by correlation analysis against mean monthly climatic variables. The native pine chronologies had the highest mean ring widths and signal-to-noise ratios (SNR), were highly correlated to each other, and exhibited positive responses to years with above-normal April temperatures but no significant relationships to variations in precipitation. The P. sylvestris chronology was highly correlated to the other two pine chronologies and responded similarly to April temperatures but exhibited negative correlations to January and April precipitation and positive correlations to September precipitation. The P. abies chronology had the highest mean sensitivity and was correlated with the P. strobus chronology but only responded positively to precipitation from the previous December. The low SNR (P. sylvestris, P. abies), high mean sensitivity (P. abies), and larger number of significant correlations to variations in monthly climatic variables (P. sylvestris) suggest that these nonnative species are more sensitive to this local climate. These results provide insights to the adaptability, establishment, and geographic distribution of the nonnative Pinaceae.

Coloradia pandora (Blake) is a phytophagous insect that defoliates Pinus ponderosa (Dougl. ex Laws.) in south-central Oregon. Little is known about the extent of damage this insect inflicts upon its host trees during an outbreak. In this paper, we present stem analyses on four dominant Pinus ponderosa trees that enable us to determine the amount of volume lost during each Coloradia pandora outbreak on this site for the past 450 years. We found that on average an outbreak inhibits radial growth so that an individual tree produces 0.057 m³ less wood volume than the potential growth for the duration of an individual outbreak. A total of 0.549 m³ of growth per tree was inhibited by 10 outbreaks during the lifetime of the trees, which, in this stand, equates to 9.912 m³/ha (1,700 board feet/acre) of wood suppressed over the last 450 years throughout the stand. Our results do not support previous findings of a lag in suppression onset between the canopy of the tree versus the base. Crossdating of stem analysis samples is paramount to definitively examine the potential for a lagged response throughout the

Dendroecological methods play a critical role in developing our understanding of forest processes by contributing historical evidence of climate variability and the temporal characteristics of disturbance. We seek to contribute to these methods by developing a research protocol for decoupling radial-growth signatures related to climate, fire, and insect outbreaks in central Oregon. Our methods are based on three independent, crossdated tree-ring data sets: 1) a 545-year tree-ring climate reconstruction, 2) a 550-year fire history, and 3) a 250-year pandora moth outbreak history derived from host (Pinus ponderosa) and non-host (Abies grandis-Abies concolor) tree-ring chronologies. Based on these data, we use visual criteria (marker and signature rings), statistical comparisons, and Superposed Epoch Analysis (SEA) to identify the timing of growth anomalies and establish the temporal relationships between drought, climate variation (ENSO and PDO), fire events, and pandora moth (Coloradia pandora) outbreaks. Our results show pandora moth outbreaks generally coincide with periods of below-average moisture, whereas fire in central Oregon often follows a period of wetter than average conditions. Fire events in central Oregon appear to be related to shifts in hemispheric climate variability but the relationship between fire and pandora moth outbreaks remains unclear.

Vor dem Hintergrund sich verändernder Umweltbedingungen durch den allgegenwärtigen Klimawandel wächst das Interesse an Vorhersagen zur zukünftigen Waldentwicklung. Der prognostizierten Häufung von Witterungsextremen wird ein wesentlicher Einfluss auf das Wachstum und die Vitalität der Waldbaumarten zugeschrieben. Wichtige Erkenntnisse bringen hier Untersuchungen zu den physiologischen Wachstumsgrenzen der Gehölze, die sich besonders deutlich an deren heutigen Verbreitungsgrenzen nachweisen lassen. An diesen offenbart sich das Potential einer Baumart, die Migration unter zukünftigen Bedingungen fortsetzen zu können. Großes Interesse herrscht an ökonomisch wichtigen Baumarten wie der Gemeinen Fichte (Picea abies [L.] Karst.) und der Rot-Buche (Fagus sylvatica L.). Deren Wuchsverhalten unter natürlichen Bedingungen, in natürlich erwachsenen Mischwäldern wurde in der vorliegenden Arbeit an den derzeitigen Arealsgrenzen beider Arten in Südschweden (Rågetaåsen, Siggaboda, Tolseboda) untersucht. Als Vergleichsstandort diente ein Naturwald im Harz (Rehberg), welcher geografisch zentral im Verbreitungsgebiet der Buche liegt und durch seine montane Höhenlage ideale Wuchsbedingungen für die Fichte liefert. Mittels dendroklimatologischer Analysemethoden wurden die wesentlichen, den radialen Zuwachs beeinflussenden Witterungsvariablen bestimmt und deren Anpassung bzw. Veränderung über verschiedene Zeitintervalle untersucht. Dendroökologische Untersuchungen ermöglichten einen Blick in die vergangene Entwicklung der Mischbestände und das Konkurrenzverhalten beider Baumarten untereinander. Diese Untersuchungen wurden auf zwei Ebenen durchgeführt: auf der Bestandesebene und auf der Ebene kleinerer Untersuchungsgruppen, durch welche direkte Konkurrenzsituationen der intra- und interspezifischen Beeinflussung analysiert werden konnten. Beide Methoden sind retrospektiver Natur und ermöglichen daher in der Hauptsache eine Analyse und Interpretation des vergangenen Zuwachsverhaltens. Doch erlauben beobachtete Trends in der Vergangenheit eine vorsichtige Prognose der Entwicklung von Waldbeständen auf vergleichbaren Standorten. Die dendroklimatologischen Analysen zeigten, dass beide Baumarten eine interessante Variabilität in den jeweiligen zuwachsbeeinflussenden Witterungsvariablen aufweisen. Die Haupteinflussgröße für den Buchenzuwachs ist ein trocken-heißer Vorjahres-Sommer mit Schwerpunkt auf den Monaten Juli und August. Dieser Einfluss zeigt sich seit Beginn des Beobachtungszeitraums, aber seit etwa 1950 verstärkt er sich bedeutend und erfährt seit Mitte der 1990er Jahre eine weitere Steigerung. Die wesentliche Witterungsvariable für den Fichtenzuwachs war bis etwa in die 1950er Jahre ein positiver Einfluss der Niederschläge im Sommer der Ringbildung mit Schwerpunkt auf dem Juni. Seither verschwindet dieser Einfluss jedoch auf fast allen Standorten und weicht einer, der Buchen ähnlichen Dürreempfindlichkeit gegenüber den vorjährigen Spätsommern. Die retrospektive Analyse der Bestandesgeschichte mittels langjähriger Zuwachszeitreihen ermöglicht eine Interpretation der vergangenen Entwicklung der Waldbestände und liefert eine Erklärung für das aktuelle Erscheinungsbild. Auf den schwedischen Standorten zeigt sich im radialen wie im Höhenzuwachs ein deutlicher Vorteil der Fichten. Auf den Standorten Siggaboda und Tolseboda bildet die Buche unter der Fichte sogar die zweite Baumschicht. Im Gegensatz zum Standort Rågetaåsen liegen diese beiden Standorte bereits außerhalb des natürlichen Verbreitungsgebiets von Buchenwäldern, aber im Gebiet der Buchen-Fichten-Wälder. Hier erkennt man deutlich einen Konkurrenzvorteil der Fichte. Am Vergleichsstandort Rehberg erkennt man dagegen das grundsätzlich große Potential der Buche, ähnliche Zuwächse zu leisten wie die Fichte. Das Konkurrenzverhältnis wirkt hier relativ ausgeglichen. Direkte Konkurrenzsituationen zwischen den Baumarten ergeben sich an Randzonen der natürlich gewachsenen reinartigen Gruppen. Es zeigte sich, dass die Buche in unmittelbarer Konkurrenz zur Fichte benachteiligt wird. Im umgekehrten Falle kann die Fichte in Abhängigkeit von ihrer sozialen Stellung sogar von einer Mischung mit Buche profitieren. Diese Ergebnisse gelten für die schwedischen Standorte wie auch für den Harz, wobei die Buchen am Rehberg ein größeres Potential erkennen lassen, dem Druck der Fichten entgegenzustehen. Der Einfluss singulärer Witterungsextreme auf das Wachstum beider Baumarten konnte an starken Zuwachseinbrüchen nachgewiesen werden. Doch in den meisten Fällen zeigte sich bereits im Folgejahr wieder ein ausgeglichenes Wachstum. Eine Herausforderung wird die zukünftige Häufung von Extremen mit fehlenden Erholungsphasen sein. Im letzten Jahrzehnt konnten bereits Sekundärfolgen großer Trockenheiten und deren Einfluss auf den Zuwachs beobachtet werden. Ergeben sich aus derartigen Situationen Schwierigkeiten für eine Baumart, ist dies ein sicheres Zeichen dafür, dass sie an ihre physiologischen Grenzen gerät. Am Standort Siggaboda konnte dies bereits für die Fichten beobachtet werden. Auch am Rehberg stellten sich in den letzten Jahren Bedingungen ein, die der Buche Schwierigkeiten bereiten. Aus den gewonnenen Erkenntnissen lässt sich entnehmen, dass das Konkurrenzverhältnis zwischen Buche und Fichte seit den letzten zwei Jahrzehnten begonnen hat, sich zu verändern. Am südexponierten Hangstandort im Harz scheint die bisher sehr konkurrenzstarke Buche an ihre physiologische Grenze zu geraten. Auf den schwedischen Standorten wird die Buche möglicherweise von wärmeren Sommern und verlängerten Vegetationsperioden profitieren, während die Fichte an die südliche, klimatische Verbreitungsgrenze der borealen Wälder gelangt zu sein scheint
Against the background of a changing environment due to climate change the interest in prognoses of the development of forest ecosystems increases. The growth and the vitality of forest tree species will mainly be influenced by increased frequency of extreme weather conditions. The analysis of the physiological limits of tree growth has to be conducted at the borders of the natural distribution range of species. Main focus lies on economical important tree species as Common beech (Fagus sylvatica L.) and Norway spruce (Picea abies [L.] Karst.).Growth and competition performance of these two species was investigated under natural conditions in naturally grown mixed forests at both species distribution limits in Southern Sweden (Rågetaåsen, Siggaboda, Tolseboda). As a reference a natural forest in the Harz Mountains (Rehberg) was chosen. By means of dendroclimatological methods the main influencing climate variables and their modifications over time were analysed. Dendroecological methods allow the retrospective analysis of forest history and the development of the competition behaviour of both species in the past. These analyses were conducted on two levels: stand level and plot level. The latter permits the analysis of direct competition situations, intra- and interspecific. By means of these retrospective methods potential trends might be detected and thus allow forecasts for the development of forest stands on comparable sites. Dendroclimatological analyses showed, that both tree species exhibit interesting variability in its main influencing climate variables. The radial growth of beech is mainly determined by warm-dry summers of the previous year with focus on July and August. This influence increases since the 1950s and even stronger since the mid 1990s. Main factor for spruce growth was summer precipitation with focus an June. This influence nearly vanished on all sites since the 1950s. Since then the main climate signal of spruce growth is a sensitivity to drought of previous summers, equally to beech. The retrospective analysis of forest history by means of long-term tree-ring series allows an interpretation of past development of the forest stands and provides explanations for the current appearance. On the Swedish sites the advance of spruce in radial as in height growth is obvious. In Siggaboda and Tolseboda beech even forms the secondary species. These sites lie beyond northern limits of Fagus forests but within Fagus-Picea forests. The advantage of spruce is considerable. Though, on the reference site Rehberg the high potential of beech, to achieve comparable tree-ring widths, is distinct. Here, the competition performance is nearly balanced. At borders of naturally grown pure groups direct competition situations between the species can be found. It could be shown, that beech is disadvantaged under immediate competition with spruce. But in inverse situations, spruce, depending on its social state, even benefits of growing in mixture with beech. These results can be found on the Swedish sites as well as in the Harz Mountains, though, beech at the Rehberg shows a much higher potential to stand against the competition of spruce. Singular impacts of extreme weather conditions on tree growth can be clearly, but in most cases growth is regulated one year later. However, future challenge for tree species will be the increased frequency of extreme conditions without phases of recovery. In the past decade secondary complications of drought and its influence on growth could already be detected. This affects both species similarly. Does a species get disadvantaged due to such situations, would mean that it reaches its physiological limits. In Siggaboda this could be already shown for spruce and at the Rehberg for beech. As a result this study shows, that the competition situation between beech and spruce has begun to change since the last two decades. On exposed sites as the Rehberg, beech trees might reach its physiological limits. On the Swedish sites, however, beech trees could benefit from warm summers and prolonged vegetation periods. In contrast, spruce probably has reached its southern, climatically determined distribution limit of boreal forests

Orientador: Leonor Patricia Cerdeira Morellato
Banca: Mario Tomazello Filho
Banca: Giuliano Maselli Locosselli
Banca: Ana Carolina Maioli Campos Barbosa
Banca: Claudio Sergio Lisi
Resumo: O conhecimento a respeito do crescimento e da formação estrutural da madeira em árvores, são preceitos básicos para entender como o clima influencia o desenvolvimento arbóreo, aqui exemplificadas pelo estudo das populações de Qualea grandiflora Mart. (Vochysiaceae), Pouteria torta (Mart.) Radlk. (Sapotaceae) e Ocotea pulchella (Nees) Mez. (Lauraceae). O objetivo deste estudo foi investigar a influência do clima no desenvolvimento do tronco das árvores de três espécies nativas do Cerrado, contribuindo assim para a sua conservação e manejo. Para alcançar esses objetivos foram realizados estudos dendrocronológicos, associados ao uso de técnicas de raios-X aplicados no lenho, utilização do conceito de manejo GOL (exploração orientada pelo crescimento), utilização de faixas dendrométricas, fenologia e anatomia cambial. Cada espécie apresentou individualidade no crescimento e houve evidente variação interespecífica. Mesmo considerando o lento crescimento cambial detectado, o incremento radial do tronco foi influenciado pelo déficit hídrico sazonal, reduzindo as taxas de crescimento nos períodos secos, e a fenologia apresentou sazonalidade nas fenofases estudadas. Por meio da construção das cronologias foi verificada a existência de correlação entre as larguras dos anéis de crescimento e clima. O crescimento das espécies foi influenciado pelas variáveis climáticas regionais (precipitação e temperatura) e possuem teleconexão com as anomalias de Temperatura da Superfície do Mar (TSM) ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The knowledge about the tree growth and wood formation is has a fundamental role for the understanding of how environment and climate have influenced the development of tree populations, here explored sstuding three cerrado species: Qualea grandiflora Mart.Vochysiaceae), Pouteria torta (Mart.) Radlk. (Sapotaceae) and Ocotea pulchella (Nees) Mez. (Lauraceae). The objective of this study was to investigate how climate influenced the development of these three species of trees native from Cerrado, contributing for their conservation and logging management. For that end, we conducted conventional dendrochronological studies associated to other techniques: wood X-ray, the management concept GOL (Growth Oriented Logging), the use of dendrometric bands, all associated to phenology and cambium anatomy. Each species showed particularites related to growth patterns and evident interspecific variation. The slow growth rate and the radial increment were influenced by the seasonal water deficit, reducing the growth rates during the dry seasons, and matched the seasonality of the observed leafing and reproductive phenology. The recovered chronologies indicated a correlation between the growth rings and the climatic variables. The growth was influenced by regional climatic variables (precipitation and temperature) and the teleconnection with the El Niño Pacific SST (Sea Surface Temperature) anomalies, but it was not related to the South Atlantic SST. Our data show adequate information on th... (Complete abstract click electronic access below)
Doutor

In der vorliegenden Arbeit wurde das Wachstum von Bergahorn und Buche mit dendroökologischen Methoden untersucht. Dies geschah vor dem Hintergrund der Ausbreitung des Bergahorns und der Eutrophierung der Landschaft. Die daran anknüpfende Fragestellung ist: Begünstigt Eutrophierung den Bergahorn? Die Untersuchung fand in einem Waldstück in Mecklenburg-Vorpommern statt. Dabei wurden von 42 Bergahornen und 38 Buchen Bohrkerne für die Vermessung der Jahrringe genommen. Weiterhin wurde neben jedem beprobten Baum das C/N-Verhältnis des Oberbodens bestimmt (n=80). Die Auswertung der Daten erfolgte durch drei Ansätze: 1.) Der Einfluss einer Hähnchenmastanlage auf beide Baumarten wurde untersucht. 2.) Die Beziehung zwischen dem C/N-Verhältnis des Bodens und dem Wachstum der Bäume wurde verglichen. 3.) Auf unterschiedlichen Standorten (C/N-Verhältnis) wurde die Abhängigkeit des Wachstums der Bäume vom Klima untersucht. Dabei wurde die Reaktion der beiden Arten auf das Klima verglichen. Die deutlichsten Ergebnisse wurden durch den zweiten Ansatz erzielt. Das C/N-Verhältnis des oberen Bodens lag zwischen 12,4 und 17,4. In diesem Bereich wurde eine positive Korrelation zwischen dem C/N-Verhältnis des Bodens und dem Wachstum der Bäume festgestellt. Die Ergebnisse deuten auf eine Schädigung der beiden Arten durch Stickstoff hin, welche beim Bergahorn (R² = 0,30) stärker als bei der Buche (R² = 0,18) ausgeprägt ist. Daraus folgt, dass der Bergahorn durch die Eutrophierung geschwächt wird. Ein Einfluss der Mastanlage auf das Wachstum der Bäume wurde nicht festgestellt. Auf das Klima reagierten beiden Arten ähnlich. Es bestand ein positiver Zusammenhang zwischen dem Niederschlag und dem Wachstum der Bäume. Der Einfluss des Standorts auf die Klimareaktion der Bäume war uneindeutig
Within this thesis the growth of sycamore (Acer pseudoplatanus L.) and beech (Fagus sylvatica L.) was investigated by applying dendroecological methods. The overall idea derived from the distribution of sycamore and the eutrophication of the environment leading to the question whether eutrophication promotes the spread of sycamore. The investigated forest was located in Mecklenburg-Vorpommern. To inspect the annual rings of the trees 42 samples were taken off the trunk of sycamore while 38 samples were gathered from beech. Apart from that the ratio of carbon and nitrogen within the topsoil of every single tree was analysed (n=80). The evaluation of the data employed three approaches. 1.) The impact of a poultry farm on both species was investigated. 2.) The relation of the C/N-ratio of the soil was compared to the growth of the trees. 3.) The connection between the growth of the trees and the climate was examined for the various sites (in terms of the C/N-ratio). Thereby the response of the species onto the climate was compared. The most precise results were achieved within the second approach. Values for the C/N-ratio of the upper soil lay between 12.4 and 17.4. A positive correlation between the C/N-ratio of the soil and the growth of the trees was discovered within this range. The results suggest an adverse effect to both of the species. This effect is more intense regarding sycamore (R² = 0,30) compared to beech (R² = 0,18). It can therefore be concluded that sycamore is weakened by eutrophication. An effect of the poultry farm on the species was not observed. Both species responded similarly regarding climate parameters. A positive relation between precipitation and growth of the trees was found. The impact of the location on the climate reaction of the trees was ambiguous

L’étude des pièces de bois de construction permet de dater le bâti (fermes, granges, pressoirs à vin, moulin, pont…) et de préciser les variations temporelles des relations entre les sociétés humaines d’une part, et la ressource-bois et la forêt d’autre part. La zone d’étude est la vallée de la Durance, et plus généralement, les Alpes françaises du sud. Le cadre temporel retenu comprend les époques médiévale, moderne et contemporaine, périodes pour lesquelles l’effectif du matériel étudiable est élevé.Le premier objectif est une meilleure connaissance du patrimoine bâti, au moyen de la dendrochronologie. Les types de bois mis en œuvre (essence, âge, calibre) ainsi que les phases d’abattage sont mises en évidence. Dans un contexte de changement de l’occupation humaine et d’aménagement du territoire, le développement de ce type d’étude est essentiel pour conserver les traces historiques de ce patrimoine fragile. Le deuxième objectif est de développer la compréhension de la relation entre le bâti et la forêt. Cette relation entre les populations humaines et la forêt ressource pose la question de l’état des forêts comme ressource au cours du dernier millénaire. L’histoire de l’occupation humaine dans les Alpes françaises du sud est ainsi questionnée. Pour répondre à la problématique, l’interdisciplinarité a été une nécessité. Un dialogue avec des historiens, archéologues, forestiers, informaticiens, charpentiers, anthracologues, gestionnaires, ingénieurs et ouvriers dans la construction et la restauration a été instauré. Et, la dendrochronologie a servi de creuset à la mise en œuvre d’une approche interdisciplinaire, dans le but de dépasser les limites de chaque discipline
Timber study makes it possible to date the traditional buildings (farms, barns, wine presses, mills, bridge ...) and specify the time variations of relationships between human societies, timber uses and forest management. The studied area is the Durance valley, from Briançon to Riez region, and, more generally, the southern French Alps. The time windowof our study is the medieval times, modern and contemporary periods, when a large amount of material (wood) is available.The first purpose of my work is to establish a better knowledge of the built heritage, using dendrochronology. We have been highlighting the types of wood used (species, age, size) as well as the trees felling and human construction phases. Given the human occupation and the land use changes, the development of this type of study is essential to preserve the historical track of this fragile heritage, witness of a mountain society in strong relationship with its environment, especially forestry. The second purpose is to develop knowledge of the relationship between buildings and forest. This relationship addresses the issue of the Alpine forests state and forest as a resource, during the last millennium. Human occupation history, in the southern French Alps, is questioned.To reach these goals, interdisciplinarity has been a necessity. Thus, a dialogue was established with historians, archaeologists, foresters, computer specialists, carpenters, anthracologists, managers, engineers and workers in construction and restoration. In order to overcome the limits of each discipline, dendrochronology has been used to implement an interdisciplinary approach

Conselho Nacional de Desenvolvimento Científico e Tecnológico
Cedrela fissilis (Vell.) is a species that has a considerable growth and a high quality wood, and because of that it is a potential species for native forests management. However, for the proper handling of this species is necessary the knowledge about its self-ecology and its dynamic in the forest. In order to contribute to the advancement of forest management in Rio Grande do Sul, we sought to evaluate the influence of morphometry (Crown proportion- Pc; range index -IA; degree of slenderness- Hd; salience index - IS; crown formal- FC), of the climate, of the presence of lianas, of soil (granulometry) and the competition (density point of Spurr), in the growing of cedro. Information was collected as regards of: circumference at breast height; overall height , commercial high, insertion height of the canopy; and eight rays of the canopy of dominant cedro trees, besides information about ecological conditions of: density point of Spurr, presence or absence of stones in soil; position on the ground; depth, presence or absence of lianas; and collected soil for particle size analysis. The increment data were obtained by the analysis of two rolls of increments, collected with the use of Pressler borer from. The morphological relationships, of IA, Hd, DBH, and crown diameter explained satisfactorily the average increase in basal area in recent years. The hypsometric relationship and range index were correlated with measures of competition. The growth was not influenced by soil texture. While Liana presence affected the productivity of cedro, trees with presence of lianas yielded less than the others. The growth was influenced by rainfall in November/December to April. The cedro trees in free conditions and with less competition were more suited to the dendroclimatic analysis. The proposed methodology: correspondence of the trend interval, for the formation of dendrochronology average, was more efficient than the methodology for obtaining the dendrochronological series average of the bigger correlations between the baguettes, because the correspondence of the trend interval, beyond include more trees in the dendrochronology mean, had a higher correlation with rain period of November/December to April, improving the correlations of monthly rain, had significant correlation with monthly November, January, march, April, for Spearman correlation with level of significant of 0.05.
Cedrela fissilis (Vell.) é uma espécie de crescimento considerável e apresenta alta qualidade de madeira, por isso, é uma espécie potencial para o manejo de florestas nativas. Contudo, para o manejo adequado desta espécie é necessário o conhecimento de sua autoecologia e a dinâmica na floresta. Com intenção de contribuir com os avanços do manejo florestal no Rio Grande do Sul, buscou-se avaliar a influência da morfometria (proporção de copa - Pc; índice de abrangência IA; grau de esbeltez Hd; índice de saliência-IS; Formal de copa Fc), do clima, da presença de lianas, do solo (granulometria) e da competição (densidade pontual de Spurr) no crescimento do cedro. Foram coletadas informações referentes à: circunferência à altura do peito; altura total; altura comercial; altura de inserção de copa e oito raios de copa das árvores dominantes de cedro, além de informações referentes às condições ecológicas de: densidade pontual de Spurr; presença e ausência de pedregosidade; posição no terreno; profundidade; presença de cipós e lianas e coletado solo para a análise granulometrica. Os dados de incremento foram obtidos pela análise de duas baguetas, coletados com a utilização do trado de Pressler. As relações morfométricas, de IA, Hd, IS, e o próprio Dap, e diâmetro de copa explicaram satisfatoriamente o incremento médio em área basal dos últimos anos. A relação hipsométrica e o índice de abrangência foram correlacionados com medidas de competição. O crescimento não foi influenciado pela textura do solo. A presença de lianas influenciou na produtividade do cedro, árvores com presença de lianas demonstraram produtividade inferior às demais. O crescimento foi influenciado pela precipitação de novembro/dezembro a abril. As árvores de cedro em condições livres e com menor concorrência foram mais aptas para as análises dendrocronológicas. A metodologia proposta de correspondência de tendência de intervalo, para formação de série dendrocronológica média, foi mais eficiente que a metodologia de obtenção de série dendrocronológica média pelas maiores correlações entre as baguetas, pois a metodologia de correspondência de tendência de intervalo, além de incluir maior número de indivíduos na série dendrocronológica média, obteve maior correlação com a precipitação do período de novembro/dezembro a abril, melhorando inclusive a correlação com relação a precipitação mensal, sendo correlacionado positivamente e significativamente com os meses de novembro, janeiro março e abril, pela correlação de postos de Spearman ao nível de 0,05 de significância.

Increases in temperature, altered precipitation patterns, and the occurrence and severity of extreme climatic events have been important characteristics of the climate change observed to date. This has had many and diverse impacts upon the living world, with one recent observation being a global reduction in the net primary production of all terrestrial vegetation. Increases in temperature and the frequency of extreme events are predicted to continue throughout the 21st century, and can be expected to have far reaching effects on global terrestrial ecosystems. Increases in temperature and drought occurrence could fundamentally impact upon the growth rates, species composition and biogeography of forests in many regions of the world, with many studies indicating that this process is already underway. European beech, Fagus sylvatica, is one of Europe’s most widespread and significant broadleaved tree species, forming an important and frequently dominant component of around 17 million hectares of forest. However, the species is also considered to be drought sensitive. Thus, much research interest has focused on eliciting the details of its physiological response to increased water stress, whilst dendroecological studies have attempted to identify sites and regions where reductions in growth might be found. A significant knowledge gap exists regarding a multi-regional, range-wide view of growth trends, growth variability, climate sensitivity, and drought response for the species. Predicting the potential effects of climate change on competition and species composition in mixed species forests remains an important challenge. In order to address this knowledge gap, a multi-regional tree-ring network was constructed comprising of 46 sites in a latitudinal transect across the species’ Western European range. This consisted of 2719 tree cores taken from 1398 individual trees, which were used to construct tree-ring chronologies for each site in the network. As a first step in a multi-regional assessment for F. sylvatica, a combination of the tree-ring chronologies and environmental data derived from a large scale gridded climate dataset were used in a multivariate analysis. Sites in the latitudinal transect were partitioned into geographically meaningful regions for further analysis. The resulting regions were then studied using climate-growth analysis, pointer year analysis of drought years, analysis of growth trends and growth variability, in order to examine regional variation in the response of the species to climate. Furthermore, a combination of long-term monitoring data from one specific site was combined with tree-ring sampling of multiple cohorts of F. sylvatica and one co-dominant competitor, Quercus petraea, to study the effects of an extreme drought event in 1976 on mortality and subsequent recovery. Key results of the multi-regional analysis are that large scale growth reductions are not evident in even the most southerly and driest portions of the species’ range. Radial growth is increasing, both in the north and in the core of the species’ range, with southern range edge forests maintaining stable growth. However, the variability of growth from year to year is increasing for all regions, indicative of growing stress. Crucially, the southern range edge, which previous studies had identified as an ‘at risk’ region, was shown to be more robust than expected. Climate sensitivity and drought impacts were low for this region. Instead, forests in the core of the species range, both in continental Europe and in the south of the UK, were identified as having the highest climate sensitivity, highest drought impacts, and experiencing periodic reductions in growth as a result. Northern range edge forests showed little sign of being affected by drought, instead having low climate sensitivity and strongly increasing growth trends. Extreme drought was found to affect species differently: the dominant species (F. sylvatica) failed to recover pre-drought levels of growth, whilst a transient effect of competitive release occurred for the co-dominant species (Q. petraea). There was also a long term effect on the relative abundance of the two species within the woodland, due to differences in the levels of drought induced mortality experienced by the species. This shows that in the case of extreme climatic events where thresholds in the ability of species to tolerate water stress are breached, the effects of drought can be rapid and long lasting. Drought impacts can cascade beyond that experienced by the most drought sensitive species, due to changes in competitive interactions between species in mixed species forests. The implications of this work suggest opportunities, risks and strengths for F. sylvatica. In the northern portion of the species’ range, predicted increases in productivity are confirmed by recent growth trends, indicating a good outlook for the species. At the southern range edge, F. sylvatica forests exist either in locations where precipitation is high or locations where local environmental conditions buffer them from an inhospitable regional climate. These factors result in southern range edge forests which are highly resilient to the effects of increasing climate stress. It is instead in the core of the species’ range where the most sensitive forests are found. The effects of extreme drought on a range core forest demonstrated here provide a cautionary note: where drought stress tolerance thresholds are breached, rapid and long lasting effects on growth and mortality can occur, even in regions where drought has not previously been considered to pose a strong risk to the species.

Plusieurs dépérissements du début du XXe siècle ont montré que le Douglas français était vulnérable à la sécheresse. La question de savoir si les forêts de Douglas peuvent s'adapter au nouveau climat plus chaud et plus sec est une préoccupation majeure en France. Nous avons estimé la variation de la résistance à la cavitation d'un ensemble de provenances de Washington, de l'Oregon et de Californie dans deux expériences de jardins communs situées dans le sud de la France. Nous avons étudié les relations entre la résistance à la cavitation, la microdensité du xylème et l'anatomie du tronc et des branches. Nous avons constaté que la pression de sélection climatique dans la zone naturelle a façonné l'adaptation locale pour la résistance à la cavitation, la microdensité et l'anatomie des ponctuations du xylème. Les provenances de Californie intérieure tendent à être plus résistantes à la cavitation, avec une plus grande densité de bois d'été et des ponctuation plus sûres que les provenances de Californie côtière, puis de Washington et d'Oregon. Cependant, nous avons également constaté des variations importantes à l'intérieur d'une même région qui ne pouvaient pas être expliquées par les données climatiques disponibles. Nous avons trouvé différentes relations structure-fonctions, selon le niveau d'observation (arbre ou provenance) et la partie de l'arbre (tronc ou branche). Par exemple, au niveau individuel, les arbres les plus résistants à la cavitation ont des branches plus denses avec une ouverture de ponctuation plus petite, tandis qu'au niveau de la provenance, les arbres les plus résistants à la cavitation ont du bois moins dense dans le tronc et les branches, et des ponctuations plus sûrs. Dans l'ensemble, nous concluons qu'il existe un potentiel d'adaptation évolutive pour la résistance à la sécheresse du Douglas, disponible à différents niveaux, individuel et de provenance. Cependant, dans un contexte d'amélioration des arbres, le réseau complexe de relations entre la résistance à la cavitation, la microdensité et les traits anatomiques doit être soigneusement examiné afin d'éviter une éventuelle réponse corrélative défavorable à la sélection
Several turn-of-the-20th-century diebacks have shown that French Douglas-fir was vulnerable to drought. Whether the Douglas-fir forests can adapt to the new warmer and dryer climate is a key concern in France. We estimated variation of resistance to cavitation traits of a set of Washington, Oregon and Californian provenances in two common garden experiments located in the south of France. We studied the relationships between resistance to cavitation, xylem microdensity and pit anatomy in the trunk and branches. We found that climatic selection pressure in the natural area has shaped local adaptation for resistance to cavitation, microdensity and pit's anatomy. Inland California provenances tend to be significantly more cavitation resistant, with a denser latewood and safer pits than coastal Californian, then Washington and Oregon provenances. However, we also found significant within region variation that could not be explained by the available climatic data. We found different structure-functions relationships, according to the observation level (tree or provenance) and the tree part (trunk or branch). For example, at the individual level, the most cavitation-resistant trees have branches with denser latewood and smaller pit aperture, while at the provenance level, the most cavitation resistant provenances have less dense wood in both trunk and branches, and safer pits. Overall, we conclude that there is a potential for evolutionary adaptation for resistance to drought in Douglas-fir, available at different levels, individual and provenance. However, in a tree improvement context, the complex network of relationships among the resistance to cavitation, the microdensity and the anatomy traits should be carefully monitored in order to avoid possible unfavourable correlative response to selection

Orientador : Prof. Dr. Franklin Galvão
Coorientador : Prof. Dr. Paulo César Botosso
Coorientador : Prof. Dr. Fidel A. Roig Juñet
Tese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Agrárias, Programa de Pós-Graduação em Engenharia Florestal. Defesa: Curitiba, 04/04/2017
Inclui referências ao final de cada capítulo
Resumo: Aspidosperma polyneuron Mull. Arg. (APOCYNACEAE), popularmente conhecida como peroba-rosa, e uma especie nativa, nao-pioneira que possui aneis de crescimento distintos a pouco distintos. Pode ser encontrada desde a Caatinga ate a Mata atlantica. Em uma area de transicao entre a Floresta Ombrofila Mista e a Floresta Estacionai Semidecidual, no Sul do Brasil, entre os meses de julho e setembro de 2011, foram coletados 40 discos do lenho de arvores de peroba-rosa (secoes transversais do fuste) a 0,40 m acima do nivel do solo. Destes, 25 provenientes de arvores crescendo naturalmente em areas de encostas e os demais (15 discos) de individuos em area da planicie de inundacao do rio Tibagi, Parana. Estas arvores foram abatidas em decorrencia da formacao do lago da Usina Hidreletrica Governador Jayme Canet Junior e compoem as amostras que deram origem aos tres capitulos desta Tese. O primeiro capitulo intitulado "A historia ambiental registrada nos aneis de crescimento de Aspidosperma polyneurori', trata da datacao, sincronizacao e padronizacao dos aneis de crescimento e a correlacao de variaveis ambientais regionais (precipitacao, temperatura, cota do rio) e globais (El-nino e SOI) com as cronologias construidas para a especie. O segundo capitulo "Dinamica e crescimento diametrico de Aspidosperma polyneurori' aborda questoes referentes ao crescimento diametrico da peroba-rosa. Investiga o tempo de passagem entre classes diametricas, com o intuito de reunir informacoes sobre a dinamica da florestal e dados sobre a autoecologia da especie. O terceiro e ultimo capitulo, "Macro e micronutrientes nos aneis de crescimento: uma nova perspectiva na analise do ambiente florestal", apresenta dados referentes ao conteudo quimico dos aneis de crescimento de A. polyneuron. Para a determinacao deste conteudo foi empregada a tecnica analitica de espectrometria de emissao optica com plasma induzido por laser (LIBS), como alternativa para estudos dendroquimicos. Palavras-chave: Dendrocronologia. Dendroquimica. Aneis de crescimento. Dinamica florestal. Macro e micronutrientes.
Abstract: Aspidosperma polyneuron Mull. Arg. (APOCYNACEAE), popularly known as Perobra-rosa, is a native, non-pioneer species that has distinct and indistinct growth rings. It can be found from the Caatinga to the Atlantic Forest biomes. Between July and September 2011, 40 wood discs (cross sections of the shaft) were collected at 0.40m above the ground level in a transition area between the Mixed Ombrophilous Forest and the Semideciduous Seasonal Forest in southern Brazil. 25 of them come from trees grown on hillsides, and the remaining (15 discs) are from individuals found on the floodplain area of the Tibagi River, in Parana State. These trees were felled as a result of the construction of the Governador Jayme Canet Junior Flydroelectric Power Plant and compose the samples that gave rise to the three chapters of this thesis. The first chapter entitled "The environmental history recorded in the growth rings of Aspidosperma polyneuron" deals with the dating, synchronization and standardization of growth rings and the correlation of regional environmental variables (precipitation, temperature, river quota) and global variables (El-nino and SOI) with the chronologies built for this species. The second chapter "Dynamic and diametric growth of Aspidosperma polyneuron" addresses questions regarding the diametric growth of the peroba-rosa. It investigates the time of passage between diametric classes, in order to gather information on the dynamics of the forest and data on the autecology of this species. The third and last chapter, "Macro and micronutrients in growth rings: a new perspective in the analysis of the forest environment", presents data referring to the chemical content of the growth rings of A. polyneuron. To determine this content, the Laser Induced Breakdown Spectrometry (LIBS) technique was used as an alternative for dendrochemical studies. Keywords: Dendrochronology. Dendrochemistry. Growth rings. Forest dynamics. Macro and micronutrients.

Submitted by Inácio de Oliveira Lima Neto (inacio.neto@inpa.gov.br) on 2017-05-11T14:35:46Z No. of bitstreams: 2 10 Tese Sejana Artiaga Rosa.pdf: 3592324 bytes, checksum: 9ff20ec80a670fb418e5cb7f37317e10 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)
Made available in DSpace on 2017-05-11T14:35:46Z (GMT). No. of bitstreams: 2 10 Tese Sejana Artiaga Rosa.pdf: 3592324 bytes, checksum: 9ff20ec80a670fb418e5cb7f37317e10 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2013-05-23
Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq
Brazil is a country of continental proportions which has 20% of its territory covered by wetland systems, distributed over all its biomes. These systems are extremely valuable, since they shelter and provide genetic resources and a huge biodiversity of flood-tolerant organisms. Wetlands also have a crucial function on the balance of the hydrological cycles and the global climate. However, any change in the hydrological cycle may strongly affect these ecosystems, since the hydrological regime is the controlling factor of the ecosystem’s biological processes. Wetlands are under great pressure due to economic development and urbanization, involving hydroelectric power plant constructions, mining and agricultural expansion. Climate change scenarios suggest temperature rise and alterations on the precipitation seasonality and amount, which can seriously affect these systems. The elaboration of conservation and management strategies for these ecosystems demands a better understanding of the hydrological and ecological processes, as well as an understanding about climate change impacts in these areas. Thus, this study aimed to contribute to the knowledge on tree growth dynamics of the Neotropical species Calophyllum brasiliense Cambess (Calophyllaceae) associated to wetlands, and found in all the Brazilian biomes. Based on tree-ring analysis it was possible to model growth of this species in diameter and volume in wetlands distributed along the Amazonian, Cerrado, Pantanal and Coastal Atlantic Forest biomes, to define criteria for forest management such as the felling cycle and minimumlogging diameters to improve practices of natural resource management of this economic important tree species. Furthermore, this study evaluated how large-scale climate phenomenon, such as El Niño-South Oscillation (ENSO) and the Tropical Atlantic meridional mode, and local climate variables such as precipitation, temperature and hydrology, affect tree growth of C. brasiliense in geographical extremes. The tree-ring analysis showed that the species presents a wide variation of diameter increment rates, which must be considered when establishing strategies for management and conservation. Moreover, estimated maximum age of C. brasiliense was almost 500 years in the nutrient-poor blackwater floodplains in Central Amazonia (igapó), however, despite the large geographical occurrence the species is not adequate for the reconstruction of climate and hydrological patterns since the majority of the individuals are not long-lived. Sea surface temperature anomalies, both in the Equatorial Pacific and in the Tropical Atlantic, have different impacts on C. brasiliense growth depending on where the species was found.
O Brasil, um país de dimensões continentais, possui cerca de 20% de seu território ocupado por sistemas de áreas úmidas, distribuídas ao longo de todos os biomas. São de grande importância, pois funcionam como abrigo e fonte de alimentos para uma infinidade de organismos, influindo no balanço do ciclo hidrológico e na estabilização do clima global. Contudo, alterações em qualquer dos componentes do ciclo hidrológico podem afetar estes ecossistemas fortemente, pois o fator controlador de seus processos biológicos é o regime hidrológico. São regiões que vêm sofrendo grandes pressões relacionadas ao desenvolvimento econômico e urbanização, envolvendo construções de hidrelétricas, mineração e expansão da fronteira agrícola. Previsões de mudanças do clima preveem alterações da sazonalidade e quantidade da precipitação e aumentos de temperatura, os quais podem afetar seriamente estes sistemas. Entretanto, elaboração de estratégias de conservação e manejo de áreas úmidas demanda maior entendimento dos processos hidrológicos e ecológicos, bem como dos impactos das mudanças do clima a que estas áreas estão sujeitas. Neste sentido, este trabalho tem por objetivo contribuir com o entendimento da dinâmica de crescimento arbóreo de uma espécie de distribuição neotropical associada aos ambientes de áreas úmidas, encontrada em todas as bacias hidrográficas brasileiras. A partir da análise de anéis de crescimento arbóreo de Calophyllum brasiliense Cambess. (Calophyllaceae) foi possível modelar o crescimento da espécie em áreas úmidas distribuídas ao longo dos biomas Amazônico, Cerrado, Pantanal e Mata Atlântica, estabelecer estratégias de ciclo de corte, diâmetro de derrubada e discutir as atuais práticas de manejo florestal desta espécie segundo o sistema GOL desenvolvido por Schöngart, (2008). Além disso, este estudo avaliou como fenômenos climáticos de larga escala, como eventos de El Niño - Oscilação Sul (ENOS) e o modo meridional de anomalias do Atlântico Tropical, e variáveis climáticas locais como a precipitação, temperatura e hidrologia afetam o crescimento arbóreo de C. brasiliense ocorrendo em extremos geográficos. As análises de anéis anuais mostram que a espécie apresenta uma ampla variação nas taxas de incremento arbóreo, o que deve ser considerado no estabelecimento de estratégias de manejo. Idades máximas estimadas chegam a quase 500 anos, porém a espécie não é adequada para a reconstrução de parâmetros climáticos e hidrológicos, pois a maioria dos indivíduos não é longeva. Anomalias de temperatura da superfície do mar, tanto no Pacífico Equatorial quanto no Atlântico Tropical, têm diferentes impactos no crescimento de C. brasiliense dependendo da posição geográfica em que a espécie se encontra.

Neste estudo analisamos a diversidade e endemismos da flora lenhosa das florestas estacionais decíduas (FEDs) do norte e centro do Perú. Caracterizamos a diversidade das plantas lenhosas ao longo dos vales, para definir os valores de conservação da área a nível nacional. Os resultados indicam que as FEDs do vale do Marañón apresentam valores significativamente altos em endemias em relação às outras FEDs do Perú e FEDs vizinhas e o padrão de endemismos e estrutura populacional das espécies variam no gradiente geográfico e altitudinal. Em constraste, as FEDs do vale do rio Tambo, centro do Perú, são moderadamente ricas em espécies do que a média das FEDs neotropicais e apresentam escassos endemismos. Esta região necessita de mais esforços de pesquisas para conhecer mais profundamente os elementos da biodiversidade. Neste estudo, também realizamos a caracterização dendro-anatômica do lenho das árvores de 87 espécies, sendo o primeiro registro da anatomia da madeira das árvores dos dois vales. Das análises do lenho das 183 espécies registradas nas florestas do norte e centro do Perú, só 157 apresentam anéis de crescimento e precisam ser analisadas em detalhe com outras pesquisas de desenvolvimento cambial e técnicas tradicionais de análises dendrocronológicas. A derivação desta informação pode alcançar alto impacto em estudos de variabilidade climática e aplicações na conservação. Assim mesmo, a análise preliminar dendrocronológica das taxas de crescimento do tronco revelam que as árvores de Cedrela kuelapensis apresentam as taxas de crescimento mais altas e ressaltam como um excelente recurso para programas de reflorestamento nos vales interandinos, além, das populações endêmicas de Cordia iguaguana e Esenbeckia cornuta são principalmente de exemplares jovens. Esperamos que as informações dos cinco capítulos constituam-se uma eficiente e importante ferramenta para melhorar a gestão dos recursos florestais dos vales estudados.
In this study we analyzed the diversity and endemism of the woody flora of Seazonally dry tropical forests (SDTF) in northern and central Peru. We characterized the diversity of woody plants along the valleys to define the conservation values of the area at the national and international levels. The results indicate that the SDTF s of the Marañón Valley show surprisingly high values in endemics in relation to other SDTF s in Peru and neighboring SDTFs, and the pattern of endemism and population structure of the species varies in geographic and altitudinal grades. In contrast, the SDTFs of the Tambo River Valley, central Peru, are moderately rich in species that average the neotropical SDTFs and have scarce endemism. This region needs more efforts to get to know the elements of biodiversity more deeply. In this study, we also performed the dendroanatomic characterization of 87 species and is the first report of the anatomy of the wood for the two valleys. From the analysis of the wood of the 183 species recorded in the forests of northern and central Peru, only 157 have growth rings and need to be analyzed in detail with other studies of exchange rate development and traditional techniques of dendrochronological analysis. The derivation of this information can reach high impact in studies of climatic variability and conservation applications. Likewise, the preliminary dendrochronological analysis of growth rates reveals that Cedrela kuelapensis showed the highest growth rates and stands out as an excellent resource for reforestation programs in the inter-Andean valleys, in addition, Cordia iguaguana and Esenbeckia cornuta endemic populations are mainly from young individuals. We hope that the information in the five chapters constitutes in efficient and important tool to improve the management of forest resources in the valleys studied.

Cedrela fissilis é uma espécie arbórea decídua com uma ampla distribuição de ocorrência na América Latina. Ocorre desde a Argentina até o Panamá, na América Central. É uma espécie que pode habitar áreas baixas de florestas, ao nível do mar e pode ocorrer em altitudes de até 1000 metros. Conhecida popularmente como cedro, cedro branco, cedro rosado, cedro missioneiro, cedro vermelho. Ela pertence a um dos gêneros de espécies mais importantes de todo o mundo para a produção de madeira, sendo por isso muito explorada. Estudos dendrocronológicos podem ajudar a entender quais fatores ambientais influenciam as taxas de crescimento da formação de lenho nas plantas. Bem como podem dar informações sobre a dinâmica de populações, o desenvolvimento e a produtividade dos ecossistemas. Devido à grande amplitude de ocorrência e a formação anual nas zonas de incremento no xilema secundário, C. fissilis é uma das espécies mais promissoras para estudos dessa natureza em regiões tropicais e subtropicais na América do Sul.
Cedrela fissilis a deciduous tree, is a species with a widespread distribution in Latin America. Occurring from Argentina to Panamá and Costa Rica in Central America. It can live in lowland forests from sea level up to 1000 m. Is popularly named as cedro, cedro branco, cedro rosado, cedro missioneiro, cedro vermelho. It belongs to a world’s economically most important timber genus from the point of view of the excellence of its wood properties, which is the reason this species has been much exploited. Dendrochronological studies would help to understand the influence of environmental factors on its growth rate and wood formation, as well as to provide valuable information on the population dynamics and on the development and productivity of ecosystems. Due to its widespread distribution and the annual formation of increment zones in the secondary xylem Cedrela fissilis is one of the most promising tree species for dendroclimatological studies in tropical and subtropical South America.

Orientador : Prof. Dr. Franklin Galvão
Co-orientadores : Prof. Dr. Paulo Cesar Botosso
Tese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Agrárias, Programa de Pós-Graduação em Engenharia Florestal. Defesa: Curitiba, 21/11/2014
Inclui referências
Área de concentração : Conservação da Natureza
Resumo: A construção da usina hidroelétrica de Mauá, sobre o rio Tibagi, removeu uma extensa área de floresta paranaense. Uma parceria formada pela UFPR e a COPEL, em 2012, permitiu o presente estudo, cujos objetivos são fornecer informações florísticas e fitossociológicas da vegetação florestal, assim como uma análise dendroecológica de Araucaria angustifolia amostrada na encosta e na planície da bacia do rio Tibagi, no município de Telêmaco Borba, Paraná. O levantamento florístico registrou elevada diversidade, totalizando 218 espécies arbóreas nativas, o que corresponde a 42% do registrado para toda a Bacia do rio Tibagi. A localização dos fragmentos nos limites latitudinais e altitudinais de ocorrência da Floresta Estacional Semidecidual (FESD) e da Floresta Ombrófila Mista (FOM) permitiu compartilhar espécies das duas unidades fitogeográficas, apontando a área como um ecótono de especial valor à conservação. O domínio das espécies clímax exigentes em luz, em conjunto com as clímax tolerantes à sombra e pioneiras, demonstra que os fragmentos se apresentam como mosaicos de fases sucessionais distintas. A classificação do continente geográfico apontou as espécies de ampla distribuição e da bacia do Paraná/Uruguai como as mais representativas em comparação com as do Atlântico e Pinhais. O levantamento fitossociológico destes ambientes manteve as mesmas características do levantamento florístico. A presença dos diques de diabásio, impondo uma pedogênese de maior trofia, somada às diferentes condições físicas, determinou que a cobertura vegetal de encosta tenha maior diversidade vegetal. O mesmo efeito foi verificado no incremento em diâmetro e altura estatisticamente (p<0,0001) superiores para o ambiente de encosta, considerando o período de crescimento em comum para Araucaria angustifolia de 223 anos. Os indivíduos de A. angustifolia analisados indicam, pela largura dos anéis, que exemplares estabelecidos após o incêndio de 1963 não tiveram restrição de recursos, já, as árvores mais velhas, possivelmente recrutadas em ambiente florestal de baixa irradiância solar, seguiram uma estratégia ecológica de sobrevivência investindo no crescimento em altura em prejuízo do crescimento diamétrico. O sincronismo entre as séries temporais de cada ambiente foi satisfatório. A extensão cronológica obtida de 370 anos (1641 - 2010) para Araucaria angustifolia fornece elementos importantes ao desenvolvimento e extensão de cronologias regionais para a espécie. A associação das variáveis meteorológicas com as séries cronológicas indicou que sinais climáticos influenciam de forma diferenciada em cada ambiente. A precipitação foi o fator limitante para os indivíduos de encosta e a temperatura o fator limitante aos indivíduos de planície, ambos coincidindo com os meses de maior liberação de crescimento. Palavras-chaves: Análise de vegetação. Dendrocronologia. Araucaria angustifolia.
Abstract: The construction of Maua hydropower plant, on the Tibagi river, located between the municipalities of Telêmaco Borba and Ortigueira, removed a extensive forest area. Thus amid a partnership formed by UFPR and COPEL, in 2012, informations and part of the extracted material from areas deforested, is used in the present study, which aims to provide informations from to a floristic and phytosociological survey of forest vegetation, and dendroecological of specie Araucaria angustifolia, both sampled in the slope and in the plain of Tibagi river, county Telemaco Borba, Parana. The floristic survey recorded high diversity, totaling 218 native arboreal species, which correspond to 42% of this in the river basin Tibagy. The location of the fragment in the latitudinal and altitudinal limits occurence of Semideciduous Forest and Ombrophilous Mixed Forest, permited to share species of two phytogeographic units, pointing the area as an ecotone of special value to the conservation. The mastery of light demanding species together with the tolerantes to shade and pioneers demonstrates that the fragment is presented as mosaic of different successional stages. The classification of geographic continent pointed species of wide distribution and Parana/Uruguay basin as more representative compared to Atlantic and Pinhais basins. The phytosociological survey such environments, kept the same characteristics of floristic survey. The presence of dykes diabase, imposing a pedogenesis higher trophic, added to different physical conditions, allowed the vegetable cover of slope greater plant diversity. The same effect was observed in diameter increment and height statistically superior to slope environment, considering the growth period in common to Araucaria angustifolia of 223 years. The individuals of Araucaria angustifolia when separate before and after the fire 1963, pointed out that young specimens were able to quickly overcome competing vegetation, since the trees old, possibly recruited in forest environment of low irradiance, followed by an ecological survival strategy investing slowly in diameter growth. The synchronism between the temporal series of each environment was satisfatory, evidencing common sinal between individuals. The chronological extension obtained 370 years (1641-2010) for Araucaria angustifolia, provides important elements for the development and extent of regional chronologies for the species. The association of meteorological variables with the chronological series found that climatic signals influence differentially in each environment. Thus, the precipitation was limiting factor for individuals on the slope and average temperature threshold of lowland individuals, both coinciding with the months increased release of growth. Keywords: Analysis of vegetation. Dendrochronology. Araucaria angustifolia.

As árvores de Tectona grandis (Verbenaceae) e de Pinus caribaea var. hondurensis (Pinaceae) são utilizadas em estudos dendroecológicos e dendroclimatológicos pela formação de anéis de crescimento anuais duas espécies plantadas na Mata da Pedreira do Campus da ESALQ/USP para estudos ecológicos e climáticos. Foram selecionadas 8 árvores de Tectona grandis (4 com e 4 sem lianas ocupando a copa das árvores) e 10 árvores de Pinus caribaea var. hondurensis (8 vivas - 4 com e 4 sem lianas ocupando a copa das árvores - e 2 mortas). Com a utilização de sondas de Pressler foram extraídas 2-6 amostras do lenho/árvore das 2 espécies para analisar seus anéis de crecimiento. Foi realizada (i) a caracterização anatômica macro e microscópica dos anéis de crescimento; (ii) estudos de dendrocronologia, pela datação e avaliação do crescimento radial do tronco das árvores; (iii) avaliação da densidade do lenho por densitometria de raios X para a determinação da densidade dos anéis de crescimento, incremento de biomassa e de carbono; (iv) avaliação da influência do clima local e em grande escala no crescimento do tronco das árvores; (v) análise dos vasos das árvores de T. grandis e dos anéis de crescimento falsos nas árvores de P. caribaea. Os resultados principais mostraram que as características anatômicas dos anéis de crescimento das árvores as 2 espécies coincidem com os descritos na literatura; a série de anéis de crescimento mostrou correlação significativa em relação à sincronização dos anéis de crescimento das árvores das 2 espécies. O efeito prejudicial das lianas na copa das árvores de T. grandis e de P. caribaea foi comprovado pela redução da largura dos anéis de crescimento no período de 2000-11 e de 1971-2011, respectivamente. A densidade aparente média dos anéis de crescimento (T. grandis: 0,64 g/cm3 e de P. caribaea: 0,60 g/cm3) permitiu calcular o incremento de massa de carbono, resultando que as árvores sem lianas apresentam maior estoque de carbono do que as com lianas. A análise dendroclimatológica mostrou que as árvores de P. caribaea apresentaram correlações positivas com a disponibilidade de água no solo no período de seca; as árvores de T. grandis mostram correlação positiva com o período de maior chuva, temperatura de primavera e a oscilação antártica (AAO) de outono no ano corrente de crescimento, e correlação negativa com o evento de El Niño (TNI) em outono anterior. A ocupação das lianas na copa das árvores de T. grandis provocou o aumento da área dos vasos; os vasos do lenho inicial (e sua frequência) mostraram correlação significativa com a largura dos anéis de crescimento, possibilitando a construção de cronologias desses parâmetros e a avaliação da influência climática nas árvores. A ocupação das lianas na copa das árvores de P. caribaea induziu diminuição da frequência dos anéis de crescimento falsos, formados, principalmente, pelo aumento das pricipatações de Julio anterior y verão (DJF) e corrente. Os resultados deste estudo permitiram concluir que a análise dos anéis de crescimento das árvores das 2 espécies tem grande potencial para estudos ecológicos e ambientais no Brasil.
The trees of Tectona grandis (Verbenaceae) and Pinus caribaea var. hondurensis (Pinaceae) are used in dendroecological and dendroclimatologal studies by formation the annual growth rings. For these reasons, the study aimed to examine the tree-rings of the two species planted in Mata da Pedreira in Campus ESALQ/USP to climatic and ecological studies. We selected eight T. grandis trees (4 with and 4 without lianas occupying the trees canopy) and 10 P. caribaea trees (8 live - 4 with and 4 without lianas- and 2 dead). With the use Pressler increment borer was extracted 2-6 wood samples/tree of two species to analyze their trees-rings growth. Were applied: i) anatomical characterization macro and microscopic of trees-rings; ii) dendrochronology studies, by dating and evaluation of the trees radial growth; iii) evaluating the density of the wood by X-ray densitometry for determination of tree-rings density, biomass and carbon increment; iv) evaluating of influence of local climate and large-scale on tree-rings; v) Analysis of the vessel in T. grandis trees and false rings in P.caribaea trees. The main results showed that the anatomical characteristics of trees-rings of the both species coincide with those described in the literature; the series of trees-rings showed significant correlation with respect to the synchronization of trees-rings in the two species. The unfavorable effect of lianas in the canopy of trees T. grandis and P. caribaea was confirmed by the reduction of the tree-rings width in period 2000-2011 and 1976-2011, respectively. . The apparent density average of tree-rings (T. grandis: 0,64 g/cm3 e de P. caribaea: 0,60 g/cm3) allowed us to calculate the increase of carbon mass, resulting that trees without lianas had higher carbon stocks than those with lianas. The climatological analysis showed that P. caribaea showed positive correlations with water availability in the soil in the dry season; T. grandis trees showed positive correlations with period of highest rainfall, temperature of spring and AAO of fall in the current growing season, and negative correlation with El Niño event (TNI) in the fall. The ocupation of lianas on T. grandis trees caused the increase of the vessels area; the earlywood vessels (and frequency) had a significant correlation with the tree-rings, allowing build of chronologies of these parameters and evaluate the influences climate in the trees. The ocupation of lianas on P. caribaea trees induced a decrease in false rings, which are formed primarily by the increase of the previous July and current summer (DJF). The results of this study showed that the tree-rings analysis of the two species has great potential to ecological and climatical studies in Brazil.

Determinadas espécies arbóreas apresentam ciclos anuais de crescimento e dormência, registrados no lenho por conspícuas estruturas anatômicas – os anéis de crescimento. Nessas árvores pode-se determinar a idade e taxas de crescimento, com resolução calendária anual, através da análise temporal dos anéis de crescimento (dendrocronologia), bem como estudar a variação dessas estruturas segundo as condições ambientais (dendroecologia). Pesquisas recentes têm descrito anéis de crescimento anuais num grande número de espécies tropicais e subtropicais. A exemplo do que ocorre em zonas temperadas e áridas, o desenvolvimento da dendroecologia pode contribuir substancialmente ao conhecimento da dinâmica do clima e da vegetação em ecossistemas tropicais e subtropicais. Nesta tese eu reviso e desenvolvo estudos dendroecológicos em biomas brasileiros, principalmente, em ecossistemas subtropicais montanos, visando solidificar a dendroecologia no país. Segundo ampla revisão bibliográfica, estudos relacionados à dendroecologia nos biomas brasileiros, em sua maioria, versam sobre a anatomia e periodicidade de formação de anéis de crescimento na flora; poucos efetivamente relacionam séries anuais de anéis de crescimento com variações do ambiente. As pesquisas estão concentradas em biomas florestais, notadamente na Amazônia. No intuito de facilitar estudos futuros, apresento uma compilação de 124 espécies que formam anéis anuais. Pesquisas inéditas sobre anéis de crescimento em Araucaria angustifolia, espécie típica de formações florestais e campestres em regiões montanas do sul e sudeste do Brasil, comprovam seu potencial dendroecológico. Através de análise da atividade cambial demonstro que esta espécie forma anéis de crescimento anuais, relacionados à variação sazonal de temperatura e fotoperíodo. Estudando séries temporais de largura de anéis de crescimento verifiquei a existência de padrões regionais de crescimento, relacionados à variação interanual do clima, principalmente da temperatura. Regionalmente, A. angustifolia parece sensível a déficit hídrico em Dezembro e Janeiro, bem como responde de forma complexa às condições térmicas em Maio e Junho. Padrões de crescimento divergente entre árvores de campo e de floresta podem estar relacionados ao regime de queimada da vegetação campestre, por sua vez, moderado pela precipitação no mês de ignição de queimadas (Agosto).
Certain tree species present annual cycles of growth and dormancy, imprinted in wood as conspicuous anatomical structures – the growth rings. Temporal analysis of annual growth rings (dendrochronology) allows the determination of tree age and growth rate, with calendar year resolution, and to study long-term relationship between tree-growth and environmental conditions (dendroecology). Recent studies have found annual growth rings in many tropical and subtropical species. As in temperate and arid zones, dendroecological investigations may contribute for understanding the dynamics of climate and vegetation in tropical and subtropical ecosystems. Here, I review and develop dendroecological studies in biomes of Brazil, aiming to support further advances. According to a broad literature review, dendroecological studies in Brazilian Biomes have focused mostly on anatomy and periodicity of growth ring formation; few of them relate growth ring time-series to environmental conditions. The studies are concentrated in forested biomes, noticebly in Amazonia. In order to assist future studies I present a compilation of 124 species that produce annual growth rings. Novel studies on Araucaria angustifolia, a typical conifer growing in forest and grassland ecosystems of south and southeast Brazilian highlands, confirm its dendroecological potential. By means of cambium activity examination I show that this species produces annual growth rings, related to seasonal variations of temperature and photoperiod. Analyses of ring-width time series revealed regional growth patterns related to inter-annual climate variations. In a regional extent, A. angustifolia trees are, probably, sensitive the water deficit in December and January, as well respond to thermal conditions of May and June, in a complex manner. Divergent patterns between grassland and forest trees may be related to grassland fire regimes, moderated by rainfall during the fire ignition period (August).

As árvores, por serem organismos sésseis, lidam com as variações ambientais, ao longo da vida, por meio de plasticidade tanto estrutural quanto funcional. As respostas a estas variações resultam em regimes de crescimento diferentes que podem ser reconstruídos por meio do estudo dos anéis de crescimento. As alterações ambientais, principalmente as alterações climáticas, têm o potencial de modular o crescimento e assim ficarem registradas nos anéis de crescimento. O estudo da interação entre a árvore e o ambiente é muito importante principalmente em um momento de transformações rápidas tanto no clima como na paisagem. O objetivo do presente estudo foi compreender como o clima e o ambiente modulam o crescimento de algumas espécies arbóreas tropicais. Neste estudo o crescimento é sinônimo de formação do lenho, o qual foi avaliado sob dois pontos de vista, o dos anéis de crescimento e o da formação do lenho com enfoque na deposição do cerne. Para isso, foram coletadas espécies de ampla distribuição, Hymenaea spp. (Leguminosaea) e Podocarpus lambertii (Podocarpaceae) que possuem anéis de crescimento visíveis. As populações de Hymenaea spp. foram coletadas em 10 localidades dentro de um gradiente latitudinal desde a linha do Equador até o Trópico de Capricórnio. A população de Podocarpus lambertii foi coletada num micro-refúgio no limite norte da distribuição desta espécie. Os resultados demonstram que tanto a precipitação quanto a temperatura influenciam o crescimento destas espécies. Estas relações entre o clima e o crescimento são dependentes do ambiente em que as árvores estão inseridas. As altas temperaturas se destacaram como um fator limitante do crescimento para as espécies estudadas. A temperatura também se destaca como um forte controlador da deposição do cerne em Hymenaea spp. Vale ressaltar que a deposição do cerne representa um alto custo para estas árvores e há um balanço entre a alocação de carbono para a formação da madeira produzida pelo câmbio e a deposição do cerne. A precipitação também é um fator importante para o crescimento destas espécies. Porém, a forma como as árvores respondem à variabilidade da precipitação parece ser dependente do ambiente em que estão inseridas. Por exemplo, árvores em ambientes de maior disponibilidade hídrica respondem melhor à precipitação da estação chuvosa, enquanto árvores em ambientes mais drenados, e menor disponibilidade hídrica, respondem à precipitação logo no início da estação chuvosa. Vale ressaltar que esta relação entre o crescimento das árvores e o clima pode ser enfraquecida pela fragmentação das florestas, tão comum nos ambientes tropicais. Conhecer como as árvores responderam a mudanças ambientais no passado é muito importante para tentar entender como elas responderão às rápidas mudanças ambientais e climáticas previstas para o futuro. De uma forma geral, um aumento na temperatura e uma diminuição na precipitação, ou uma concentração das chuvas em uma estação chuvosa mais curta, provavelmente terão um impacto negativo sobre o crescimento destas árvores. Entretanto, este efeito será dependente das condições ambientais nas quais as árvores estarão inseridas.
Trees are sessile organisms that relate with constant environmental change through both structural and functional plasticity. Changes in the plasticity result in different growth rates through the life of trees that can be accessed by the study of tree rings. Environmental changes, especially climate, have the potential to modulate tree growth and, consequently, be recorded in the tree rings. The study of the interaction between trees and the environment is relevant in a time of fast changes in the landscape and climate. The aim of this study was to better understand how climate and landscape features modulate the growth of tropical tree species. In the present study, growth is analyzed as a synonym of wood formation. Additionally, it was analyzed under two points of view, the first one is the tree-ring analyzes and second one is the carbon allocation in the process of wood formation. To accomplish that, tree species with wide distribution were sampled, including Hymenaea spp. (Leguminosae) and Podocarpus lambertii (Podocarpaceae) both with distinct tree rings. The populations of Hymenaea spp. were sampled in ten sites across a latitudinal gradient from the Equator line to the Tropic of Capricorn. The population of P. lambertii was sampled in a micro refuge in the northern limit of this species distribution. Results show that both temperature and precipitation influence these species growth and that relation depends on the environment in which trees grow. High temperatures seem to be a key limiting factor for the studied specie growth. Moreover, temperature is also an important factor that controls the heartwood deposition in Hymenaea spp. It is important to note that the heartwood deposition represents a high carbon cost for these trees. Additionally, there is a trade-off between in the carbon allocation between the sapwood as produced by the cambium and the heartwood deposition. Precipitation is also a climate variable that influences these species growth. However, the precipitation influence seems to be more dependent on the environmental features of each population site. For instance, in sites higher water availability, trees\' growth is more dependent on the precipitation during the wet season, while in sites with lower water availability, and well-drained soils, trees\' growth is more dependent on the precipitation during the transition period between dry and wet seasons. It is important to highlight that forest fragmentation, commonly seem in tropical areas, has the potential to make this climate/growth relations weaker. Overall, an increase in air temperature and a decrease in the precipitation, or a concentration of it in a shorter wet season, will likely have a negative impact on trees growth. However, this effect will depend on the environmental characteristics of each population.

Submitted by Gizele Lima (gizele.lima@inpa.gov.br) on 2017-11-06T14:15:51Z No. of bitstreams: 2 Dissertação - Victor LC Andrade -CFT INPA.pdf: 1497227 bytes, checksum: c2d78ac63d792e8aa52b29f8abfc9135 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)
Made available in DSpace on 2017-11-06T14:15:51Z (GMT). No. of bitstreams: 2 Dissertação - Victor LC Andrade -CFT INPA.pdf: 1497227 bytes, checksum: c2d78ac63d792e8aa52b29f8abfc9135 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-04-28
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
From the moment Humans arrived in the Amazonian region, at least 12 ky ago, they started managing the forest, in a long term domestication process, yet with the indigenous demographic collapse after 1492, this ancient human-forest relationship may have been partially lost. Bertholletia excelsa Bonpl. (Lecythidaceae) is an iconic nut tree that dominates vast swaths of the Amazon forest, and known for being used, managed and domesticated by humans since before the European arrival. Considering the intimate historical relationship between humans and the Amazon nut tree, it remains unclear if the long term population dynamics of this species within the forest has been driven by management practices, and if this interaction changed following the collapse of pre-colonial societies. Here we reconstruct over 300 years of population dynamics for a living Amazon nut tree stand in Central Amazonia, and relate this dynamics with human history in that region. For this we combine the analyses of tree-rings that may reveal how tree recruitment and growth rates changed through time, with historical information on the main political and economical facts that may have impacted the lives of indigenous and colonists. Our results reveal that the intensification of political dominance over the colony around 1800 coincided with sharp reductions of recruitment and growth rates of B. excelsa, suggesting the abandonment of indigenous management practices. A more recent recruitment pulse in the 20 th century, associated with unprecedented cycles of growth release and suppression, suggest a new management phase involving non-indigenous practices. Our findings suggest that humans have historically shaped nut tree population dynamics across the Amazon, and allude to the loss of ancient management knowledge with the collapse of pre-Columbian societies.
Desde o momento em que os seres humanos chegaram à região amazônica, pelo menos a 12 mil anos, começaram a manejar a floresta, em um processo de domesticação de longo prazo. Mas com o colapso demográfico indígena após 1492, essa antiga relação entre humanos e florestas pode ter sido parcialmente perdida. Bertholletia excelsa Bonpl. (Lecythidaceae) é uma árvore icônica que domina vastas áreas da floresta amazônica e conhecida por ser usada, manejada e domesticada por humanos desde antes da chegada europeia na Amazônia. Considerando a íntima relação histórica entre os seres humanos e a castanha da Amazônia, ainda não está claro se a dinâmica das populações a longo prazo dessa espécie dentro da floresta foi conduzida por práticas de manejo e se essa interação mudou após o colapso das sociedades pré-coloniais. Aqui, reconstruímos mais de 300 anos da dinâmica populacional de um castanhal na Amazônia Central e relacionamos com a história humana nessa região. Para isso, combinamos as análises de anéis de crescimento que podem revelar o modo como as taxas de recrutamento e crescimento das árvores mudaram ao longo do tempo, com informações históricas sobre os principais fatos políticos e econômicos que podem ter impactado a vida de indígenas e colonos. Nossos resultados revelam que a intensificação do domínio político sobre a colônia em torno de 1800 coincidiu com fortes reduções de recrutamento e taxas de crescimento de B. excelsa, sugerindo o abandono das práticas de manejo indígena. Um pulso de recrutamento mais recente no século 20, associado a ciclos sem precedentes de liberação e supressão de crescimento, sugerem uma nova fase de gerenciamento envolvendo práticas não-indígenas. Nossas descobertas sugerem que os seres humanos têm historicamente dado forma a dinâmica da população de castanheiras, e aludem à perda do antigo conhecimento de manejo florestal com o colapso das sociedades pré-colombianas.

El objetivo principal que se plantea en el presente trabajo es determinar la plasticidad del crecimiento radial del pino carrasco (Pinus halepensis Mill.) frente al clima. Más concretamente, evaluar el grado de adecuación del crecimiento en grosor del tronco de las masas forestales de esta especie, a las distintas condiciones climáticas que se encuentran dentro de su área de distribución en España. Dicho propósito se aborda mediante el análisis de las series de crecimiento radial y su relación con el clima a distintas escalas temporales y espaciales. Una primera perspectiva se basa en el seguimiento (realizado con resolución casi quincenal) del crecimiento radial del pino carrasco en una localidad situada dentro del Parc Natural del Garraf (Barcelona, Catalunya). La finalidad de este seguimiento es precisar el grado de ajuste de las tasas de crecimiento radial del pino carrasco a la variabilidad climática inter e intraanual. Dicho de otro modo, delimitar los períodos de actividad y reposo del crecimiento en grosor del tronco y definir qué factores climáticos controlan la formación de los anillos de crecimiento. Los objetivos parciales que se plantean son: (i) Establecer el patrón temporal del crecimiento radial (períodos de crecimiento y reposo). (ii) Determinar el grado de ajuste del crecimiento radial de la especie a la variabilidad climática inter e intraanual a lo largo de los 10 años del seguimiento. (iii) Identificar los factores que determinan las tasas de crecimiento en grosor del tronco, sus efectos en las sus características anatómicas del anillo de crecimiento y, la periodicidad con la que dichos anillos se forman. Los resultados derivados de este seguimiento intensivo del crecimiento radial constituirán una base sólida para la interpretación de los resultados obtenidos en el estudio dendroclimático del pino carrasco en España, el cuál se basa en una red de cronologías del grosor de los anillos de crecimiento lo más extensa posible (temporal y espacialmente). Los objetivos en los que se desglosa este segundo propósito son los siguientes: (i) Establecer una red de localidades representativa del área de distribución de la especie, de los bioclimas en los que habita y del tipo de masas forestales que encontramos en España; y describir detalladamente el clima de cada una de ellas, sus peculiaridades y sus tendencias temporales. (ii) Caracterizar ecológicamente los bosques españoles de pino carrasco, mediante dos parámetros: Uno, la descripción de la estructura demográfica de edades y por tamaños y de las características actuales de las masas forestales (densidad, área basal, estructura espacial, etc.); y dos, la reconstrucción de su historia reciente (últimos 100 años) y obtención de su régimen de perturbaciones. (iii) Establecer las relaciones entre el crecimiento (series del grosor de los anillos) y las condiciones climáticas locales, y de su variación a lo largo del este de la Península e Islas Baleares, resaltando el grado de adecuación del crecimiento radial del pino carrasco al clima en las distintas regiones bioclimáticas en las que se halla. (iv) Analizar la variación espacial de los patrones de crecimiento radial de la especie en España y de su relación con el clima a escala regional; y valorar el grado en que dichas variaciones regionales pueden estar relacionadas con fenómenos de circulación atmosférica de escala global (teleconexiones climáticas). (v) Contrastar la estabilidad temporal de las relaciones crecimiento-clima a escala local y regional. La interpretación de los resultados obtenidos proporcionarán una visión global y precisa de la respuesta al cambio climático que pueden tener los bosques españoles de pino carrasco, la especie más importante en el paisaje español de baja altitud, no sólo por el área de territorio que ocupa sino por su importante función ecológica (ej. prevención de la erosión y perdida de suelo y recuperación del entorno natural después de perturbaciones, especialmente incendios).

En raison de son aire de repartition limitee au bassin mediterraneen occidental et de son utilisation actuelle et passee, le genevrier thurifere, cupressacee arborescente developpee essentiellement en milieu montagnard mediterraneen, revet un interet biogeographique et culturel reconnu. L'etude dendroecologique presentee ici, menee dans deux peuplements geographiquement tres distincts (pyrenees francaises et haut-atlas marocain), contribue a la comprehension des facteurs environnementaux gouvernant les processus de croissance et de leur expression differenciee selon les biotopes de son aire generale de repartition. L'analyse des relations entre les variations interannuelles du climat et l'epaisseur des cernes de croissance souligne le fort assujettissement de la croissance radiale annuelle de l'arbre au bilan hydrique estival, ainsi qu'aux conditions climatiques de la periode precedant l'elaboration du cerne (automne et hiver). Le comportement opportuniste du thurifere vis a vis des precipitations, qui s'exprime a travers l'elaboration de cernes doubles et de cernes absents, revele une adaptation physiologique de l'arbre a la secheresse. Ces recherches ont ainsi mis en evidence combien, dans les ecosystemes montagnards semi-arides, le climat intervient fortement sur la croissance, a travers la disponibilite en eau et les temperatures, et comment l'altitude peut en modifier l'expression. Malgre une croissance lente et complexe, et en depit de la forte pression anthropique qu'il subit notamment dans les atlas marocains, le genevrier thurifere se revele un bon integrateur des variations climatiques locales et des evenements macroclimatiques extremes. Du fait egalement de sa longevite, il apparait comme une essence propice a l'analyse dendroclimatologique et pourrait ainsi constituer un modele d'etude approprie pour les predictions des effets des changements climatiques globaux sur les ecosystemes semi-arides mediterraneens d'altitude.

Die Trauben-Eiche (Quercus petraea [MATT.] LIEBL.) ist ökologisch wie ökonomisch eine prägende Baumart im nordostdeutschen Tiefland. Seit längerer Zeit haben jedoch lokal bis regional drastische Vitalitätseinbußen zu Diskussionen um ihre Verwendbarkeit für den Wald der Zukunft geführt. Vor dem Hintergrund fortschreitender Veränderungen des Klimas stellen sich Fragen nach der Anpassungsfähigkeit der Baumart im Sinne der Überlebensfähigkeit, nach den Beziehungen zwischen Vitalitätszustand und Wuchsverhalten sowie nach möglichen Entwicklungstendenzen dieser Parameter. Die vorliegende Arbeit untersucht die Zusammenhänge zwischen Vitalität und Zuwachs sowie die Effekte der Witterung auf die Jahrringbreite als wesentlichem Vitalitätsindikator. Die retrospektive Analyse dieser Beziehungen dient dazu, das mögliche Verhalten des Witterungs-Zuwachs-Komplexes in der Zukunft abzuschätzen und damit die Risiken einer forstlichen Schwerpunktsetzung auf die Trauben-Eiche in Nordostdeutschland genauer zu fassen. Die Untersuchungen fußen auf zwei Versuchsflächen-Sets. Die Kernflächen K1-K5 umfassen fünf Mischbestände aus Trauben-Eichen und Kiefern (Pinus sylvestris L.) entlang eines Gradienten von Sachsen-Anhalt bis Ostpolen im Altern von etwa 110-150 Jahren auf Standorten mittlerer Nährkraft und durchschnittlicher Wasserversorgung. Dieses Set wird erweitert durch 20 Zusatzflächen im Osten bis Süden des Landes Brandenburg, ebenfalls zum größten Teil in Mischbeständen mit Kiefer. Neben den ertragskundlichen Basisaufnahmen wurden auf den Versuchsflächen Bohrkerne an Stichproben des herrschenden Bestandes entnommen. Zu allen Flächen liegen die Angaben der forstlichen Standortkartierung über die Nährkraftstufe und die Wasserversorgung sowie Zeitreihen von Tagesmitteltemperaturen und Niederschlagstagessummen vor. Als Szenariodaten werden die Medianläufe des 2-Kelvin-Szenarios mit dem Regionalisierungsmodell STAR 2 auf Grundlage des SRES-A1B-Szenarios verwendet. Zur Einschätzung der Vitalität der Trauben-Eichen in den Untersuchungsbeständen wurde 2006-2011 der prozentuale Laubverlust im Sommerzustand nach dem Standard der Waldzustandserhebungen erfasst (EICHHORN et al. 2006). Parallel wurde der Kronenzustand im Winter nach dem Schema von KÖRVER et al. (1999) beurteilt. Als Indikatoren für die Vitalität der Trauben-Eichen standen die Jahrringbreite und die Zuwachsrate ("Jahrringindex") im Mittelpunkt der Untersuchungen. Für die Zeitreihen der Jahrringbreite wurden die Parameter Autokorrelation und Sensitivität für die gesamte Zeitreihe sowie als gleitende Mittel hergeleitet und interpretiert. Im Programmpaket "CLIMTREG" (BECK et al. 2013) erfolgten anschließend die Trendeliminierung und die AR(1)-Modellierung zur Entfernung autokorrelativer Effekte aus den baumspezifischen Jahrringindex-Zeitreihen. Die Identifikation von Weiserjahren stützte sich auf die Verteilungsparameter Mittelwert und Standardabweichung der Einzelbaum-Jahrringindizes pro Jahr. Aus den individuellen Zeitreihen des Jahrringindexes wurde die mittlere bestandesbezogene Index-Zeitreihe (= Chronologie) errechnet. Zur Quantifizierung der Witterungs-Zuwachs-Beziehungen wurden die Analyse-Tools CLIMTREG (mit tagesgenauer Auflösung) sowie "bootRes" für R (monatliche Auflösung; ZANG & BIONDI 2012) verwendet, in die Daten der jeweils nächstliegenden Wetterstationen sowie Zeitreihen des mittleren Jahrringindexes eingesteuert wurden. Die Auswertungen zeigten, dass sich im Untersuchungszeitraum 2006-2011 Belaubungsgrad und Kronenstruktur für die Mehrzahl der untersuchten Bäume deutlich verbessert haben. Mit dem relativen Kreisflächenzuwachs ist die Kronenstruktur (hochsignifikant) über alle Kernflächen hinweg straffer positiv korreliert als der Laubverlust (nicht signifikant). Bei gleichem BHD sind größere Kronenflächen sowohl mit besseren Kronenstrukturwerten als auch mit einem geringeren Laubverlust gekoppelt. Der jährliche Radialzuwachs nimmt im Mittel der Kernflächen seit mehreren Jahrzehnten zu. Auf den Zusatzflächen liegen die mittleren Jahrringbreiten etwa auf Ertragstafelniveau (ERTELD 1963). Die absolut und relativ höchsten Zuwächse 2006-2011 zeigten die polnischen Kernflächen. Die Korrelationen der Jahrringindizes (JRI) mit dem Niederschlag sind etwas straffer als mit der Temperatur, aber nur selten signifikant. Die für die Vegetationsperiode berechneten Korrelationskoeffizienten sind in keinem Fall höher als die für das Gesamtjahr ermittelten. Bei der Prüfung dendroklimatologischer Zusammenhänge auf Monatsebene mit bootRes zeigen die Flächen K1 und K3 ein ähnliches Bild: Höhere Jahrringindizes sind mit überdurchschnittlichen Niederschlägen vor allem in den Wintermonaten sowie im Spätsommer bis Frühherbst des Wuchsjahres gekoppelt. Auf den übrigen Kernflächen sind die Zusammenhänge im Vergleich weniger straff. Zwischen herrschendem und beherrschtem Bestand gibt es kaum Unterschiede in der Reaktion des Jahrringindex auf die Witterung. Die Beziehungen zu den Mitteltemperaturen sind etwas schwächer ausgeprägt. Auf allen Flächen sind vorrangig kühle Spätfrühlings- und Frühsommermonate mit überdurchschnittlichen Jahrringindizes verbunden. Analysen durch moving windows zeigen für einige Flächen im Lauf der Zeit zunehmende Korrelationen zwischen Witterung und Jahrringindex. In Zusammenfassung aller Flächen ergeben sich für die zweite Hälfte der Untersuchungsperiode deutlich mehr signifikante Zusammenhänge als in der ersten. Nach den Auswertungen mit CLIMTREG führen fast überall hohe Niederschläge bei niedrigen Temperaturen im Hochsommer des Vorjahres zu überdurchschnittlichen Zuwachsraten. Außerdem fördern erhöhte Niederschlagsmengen von Ende November bis in den Februar, zum Teil auch höhere Temperaturen, die Jahrringbildung. Das dritte auffällige Intervall ist die Zeit von Anfang April bis Mitte Juli mit höheren Zuwachsraten bei niedrigen Temperaturen und überdurchschnittlichen Niederschlägen. Die Modellierung von Jahrringindex-Zeitreihen für den Szenariozeitraum 2001-2055 auf Basis unterschiedlicher Kalibrierungszeiträume ergibt in den meisten Fällen die höchsten mittleren Jahrringindizes (JRI) für das mit der zweiten Hälfte des Gesamtuntersuchungsintervalls 1951-2006 parametrisierte Modell. Im Vergleich unterschiedlicher Kalibrierungszeiträume verändern die von CLIMTREG identifizierten zuwachswirksamen Zeiträume in der Regel weder ihre Lage noch ihre Länge in wesentlichem Ausmaß. Auffällig ist jedoch, dass die Richtung der Zusammenhänge in der jüngeren Vergangenheit uneinheitlicher wird. Auf Basis der Untersuchungsergebnisse leitet die Studie Chancen und Risiken ab, die für die Trauben-Eiche unter dem Einfluss des genutzten Witterungsszenarios im Untersuchungsgebiet maßgeblich sind. Die Handlungsoptionen zum Stärken der Anpassungsfähigkeit umfassen im Wesentlichen die Steuerung der negativen und positiven Einflüsse, die dem menschlichen Einfluss zugänglich sind. Dazu gehört die Förderung der individuellen Vitalität und Elastizität durch optimal entwickelte Kronen und Wurzelsysteme. Die Mischung mit anderen Baumarten steigert die Bestandesstabilität, wobei die relative Konkurrenzschwäche der Eiche zu berücksichtigen ist. Verjüngungsmaßnahmen sollten auf die Erhaltung und Steigerung der genetischen Vielfalt ausgerichtet sein und Individuen mit überdurchschnittlicher Vitalität besonders fördern. Die Konkurrenz um Wasser kann – unter Beachtung des Risikos zusätzlicher Verdunstung –durch geringere Bestandesdichten reduziert werden. Die größten Erfolgsaussichten für diese Aktivitäten bestehen auf Standorten höherer Wasserspeicherkapazität und Nährkraft. Ein angepasstes Monitoring sollte Bedrohungen zum Beispiel durch Insektenmassenvermehrungen rechtzeitig erkennen, gegen die alle Bekämpfungsmöglichkeiten auszuschöpfen sind. Auf gesellschaftlicher Ebene ist eine umfassende Diskussion zu den Zielen und Methoden der Waldbewirtschaftung zu führen, um eine höhere Wertschätzung und Langfristigkeit gezielter Eichenförderung zu erreichen
Sessile oak (Quercus petraea [MATT.] LIEBL.) is an important tree species in the northeastern lowlands of Germany. The widespread introduction of the species into mature Scots pine (Pinus sylvestris L.) stands as a means of ecological forest conversion has further enhanced its relevance in forest science and management. For a few decades, however, increasing numbers of trees and stands showing a severe decline in vitality have led to critical discussions on the possible role of oaks in today's forest development strategies. The adaptive capacity of Sessile oak will be further challenged by climate change in the future. In this context, more information is needed on the relations between the vitality status and growth, including the development of these relations in the next decades. Thus, the study investigates the dependencies between annual radial increment in Quercus petraea (measured as tree-ring width, TRW) and individual-tree vitality as well as the effects of climatic variables on TRW on different temporal scales. Investigations were carried out using two sets of trial plots. The core plot sequence K1-K5 comprises five mature mixed stands of Sessile oak with Scots pine along a gradient from Saxony-Anhalt to eastern Poland. Trees are 110-150 years old and grow on sandy and partly podsolic cambisols with average water supply. A set of 20 additional plots was established in mixed oak-pine stands in Brandenburg. In addition to growth and yield data for the whole plot, increment cores were extracted from a representative sample of 20 trees per plot. Time series data of local daily mean temperatures and daily precipitation sum were provided by the Potsdam-Institute for Climate Impact Research. Data for 2007-2060 come from the median scenario of the regional climate model "STAR 2" based on the SRES-scenario A1B and assumes an increase in temperature of two Kelvin until 2060. Individual vitality was recorded from 2006 to 2011on the core plots (i) according to the European standard method for the assessment of crown condition based on defoliation percentages in summer (EICHHORN et al. 2006) and (ii) following the approach by KÖRVER et al. (1999) for crown structure classification in winter. Both methods were applied to all dominant and co-dominant oaks in the five subsequent years. Trees on the additional plots were assessed only once. Because they are regarded a reliable indicator of tree vitality, annual radial increment as expressed in tree-ring width (TRW) and the resulting growth rate (tree-ring index) are at the center of the analyses. For TRW time series the parameters autocorrelation and sensitivity were calculated both for the whole investigation period and as floating means ("moving windows"). The program "CLIMTREG" (BECK et al. 2013) was applied to eliminate long-term trends in individual TRW series by means of cubic spline functions and to minimize auto-correlation within the resulting TRI time series. Pointer years were identified on the basis of the mean and standard deviation of annual TRI distributions. Plot-specific "chronologies" were calculated as arithmetic means of all "typical" tree-specific TRI series per plot. To analyze the relations between climate and growth, the programs CLIMTREG (for daily climate data resolution) and "bootRes" for R (monthly resolution; ZANG & BIONDI 2012) were applied to local climate data and the TRI chronologies. The repeated assessments show that during the interval 2006-2011 crown condition as expressed in summer foliage as well as in crown structure has improved considerably. Crown structure values are correlated more closely to individual basal area increment than defoliation percentages. At the same DBH, trees with larger crowns exhibit a significantly better crown structure and less defoliation. Annual radial increment has been increasing on the core plots over the past decades, thus the increment level of the dominant trees is on average slightly higher than that of the first yield class in the table by ERTELD (1963). On the additional plots, mean TRW is parallel to yield table values but shows a slowly decreasing trend in a number of stands. The two core plots in Poland exhibited the highest radial increments 2006-2011, both absolutely and relatively. On the annual level, TRI time series are correlated more closely to precipitation sums than to annual mean temperatures. Except for one of the additional plots, the respective correlation coefficients are statistically insignificant. Correlations did not increase when climate parameters were calculated exclusively for the vegetation period instead of the whole year. According to dendroclimatological analyses on the monthly scale with bootRes, trees on core plots K1 and K3 respond almost similarly to climatic influences: High TRI values are related to above-average precipitation mainly during the winter months, as well as in late summer and early fall of the year of growth. On the other core plots, dependencies are less clear. The relations of TRI to monthly temperature are weaker than those to precipitation with the same ranking of plots regarding their sensitivity. The most favorable influence on TRI is exerted by cool spring to early summer months in the year of growth. Correlation patterns are very similar for both dominant and suppressed trees. Separate analyses of the first and the last half of the investigated interval show that the strength of correlations between TRI and climatic variables has been increasing over the past decades. When summarized over all plots, there were distinctly more significant correlation coefficients in the period from 1984-2006 than from 1951-1983. The analyses using CLIMTREG showed that high summer precipitation in the preceding year clearly promotes above-average TRI values. Another conspicuous climate-influenced time period ranges from late November to February with positive correlations both to precipitation and to temperature (at least partly). The third important period for TRI in most trees on the core plots starts in early April and lasts until Mid-July. During this time, high TRI values are correlated with low temperatures and high precipitation. For most of the plots, the average modeled TRI is higher if the second half of the data interval 1951-2006 is used for calibration rather than the entire interval or its first half. The results of the models based on different calibration periods do not differ very much in terms of the identified variables (i.e. length of influential period and type of climatic parameter). However, the direction of correlations becomes more variable in the more recent past. The results of this study are summarized in a number of risks and opportunities regarding future vitality and growth of Sessile oak under regional conditions. Finally, several options of silvicultural management to support vitality and growth of the species are recommended. These consist basically in promoting favorable conditions and limiting negative influences. A large crown with dense foliage and a well-developed root system are crucial conditions for individual vitality which should be strengthened for instance by reducing stand densities at an early age. Mixed stands have a higher stability towards disturbances and provide more diverse habitats for natural antagonists against defoliators. The relatively weak competitiveness of oaks should be taken into account when advocating mixed stands. Regeneration activities should enhance genetic diversity, promote phenotypes with above-average vitality, and accelerate the adaptation of the species by "assisted migration" of drought-tolerant provenances. Competition for water may be eased by lower stand densities. However, the canopy should be kept sufficiently closed to prevent excessive growth of ground vegetation or increased evapotranspiration. An adapted system to monitor forest growth and vitality should be used to technically assist the species in counteracting major insect outbreaks and other severe biotic risks as early as possible. On a more general level, productive discussions are needed between all stakeholders, interest groups, and the public on the social and political role of forests and the required level of management. This should lead to a stable social and political appreciation of forestry and provide the resources and staff necessary to cope with an uncertain future

O Estado de Sergipe, apesar de ser o menor entre os estados da confederação, apresenta uma grande diversidade de ambientes. Sob o regime climático litorâneo, florestas tropicais prosperam contanto com grande disponibilidade hídrica, enquanto no interior, formações florestais rústicas crescem em um dos ambientes mais secos do Brasil. A dendrocronologia trata-se de uma ciência fundamentada em uma série de princípios, que devem ser atendidos em sua totalidade, e assim o foram nos diversos ambientes de Mata Atlântica/Caatinga sergipanos. Esta ciência, capaz de proporcionar estimativas acuradas da idade das árvores, sua dinâmica na comunidade, e relação com o clima, foi utilizada neste trabalho em busca de seu objetivo, tido como o estudo da espécie Cedrela odorata, e a influência de diversos fatores ambientais sob seu crescimento diamétrico, periodicidade de formação dos anéis de crescimento e para o desenvolvimento de cronologias a partir dos mesmos. A pesquisa foi desenvolvida em três diferentes sítios, localizados nos extremos geográficos do Estado de Sergipe, sob o domínio de atuantes climáticas díspares. Amostras de lenhos foram retiradas no DAP do tronco para as avaliações dendrocronológicas, de densitometria de raios X e isotópicas. Verificou-se a presença de grande sazonalidade climática e fenológica em todos os ambientes. Observou-se que a formação dos anéis de crescimento destas árvores foi regulada principalmente pela precipitação da estação corrente de crescimento e pela temperatura da estação anterior à esta, indicando que possuem potencial para estudos paleoclimáticos. A análise isotópica exibiu a tendência de diminuição dos valores de ?13C ao longo dos anos e o aumento dos valores da Eficiência do uso da água (iWUE). Houve diferença significativa no ritmo de crescimento do tronco das árvores entre os diferentes sítios, porém em todos eles a formação anual dos anéis de crescimento e sua relação com o clima foi confirmada, principalmente para o inédito ambiente de Caatinga, que agora pode ser inserido no cenário internacional de estudos dendrocronológicos.
The State of Sergipe, despite being among the smallest states of the confederation, has a wide range of environments. Under the regime coastal climate, rainforests thrive provided with great water availability, while inside, rustic forest formations grow in one of the driest environments in Brazil. Dendrochronology it is a science based on a series of principles that must be attended in its totality, and so they were in the different Tropical Rainforest/Caatinga environments in Sergipe. This science, capable of providing accurate estimates of trees age, their community dynamics, and relation to climate, was used in this work in pursuit of his goal, considered to be the study of the species Cedrela odorata, and the influence of several environmental factors on its diameter growth, timing of formation of the growth rings and for developing chronologies out of the same. The research was conducted at three different sites, located in the geographical extremes of the State of Sergipe, in the grip of disparate operating climate. Sample logs were removed from the trunk\'s DBA to the dendrocrhonological assessments, X-ray densitometry and isotopic. There was the presence of large climatic and phenological seasonality in all environments. It was observed that these trees growth rings formation is governed mainly by the current station precipitation and the prior station temperature, indicating that they have potential for palaeoclimatic studies. Isotopic analysis showed a trend of decreasing ?13C values over the years and the values increased efficiency of water use (IWUE). There was significant difference in the rate of growth of the tree trunk between the sites, but in all of them the formation of annual growth rings and their relationship with climate was confirmed, especially to the unprecedented Caatinga environment, which now can be inserted into the international scenario of dendrochronological studies.

La plasticité phénotypique permet aux génotypes de s’ajuster à des variations environnementales. Dans cette thèse nous avons utilisé des caractères de cernes annuels de mélèzes pour estimer la plasticité phénotypique à deux échelles de temps: entre années (chap. 1, plasticité interannuelle) et dans l’année (chap. 2, plasticité intra-annuelle). Dans le chap. 1 nous avons analysé des cernes annuels de mélèzes d’Europe distribués dans quatre placettes le long d’un gradient altitudinal naturel de la région de Briançon, dans les Alpes françaises. La plasticité phénotypique de la croissance radiale et de la densité du bois final en fonction de la température maximale tend à être négative à basse altitude (1350 m) et surtout positive à haute altitude (2300 m), où le mélèze d’Europe semble réagir favorablement à l’augmentation de la température. Aucune tendance altitudinale ne se dégage pour la densité du bois initial, qui présente en majorité une plasticité négative ou nulle. La plasticité phénotypique de la densité moyenne du cerne est intermédiaire entre celle du bois initial et celle du bois final. Dans le chap. 2 nous avons utilisé des courbes de croissance radiale intra-annuelle enregistrées à l’aide de dendromètres automatiques pendant quatre années dans un dispositif combinant plusieurs régimes hydriques et trois espèces de mélèze. Nous en avons extrait des variables de plasticité phénotypique pour la croissance radiale et la dynamique de l’eau dans le tronc en fonction de plusieurs variables climatiques. Toutes variables de plasticité phénotypique et toutes conditions environnementales confondues, l’hybride est un peu plus plastique que le mélèze du Japon et beaucoup plus que le mélèze d’Europe, ce qui traduit sa capacité à reconstituer et à utiliser rapidement et efficacement cette réserve en eau. Nous faisons l’hypothèse que cela contribue à sa plus grande vigueur. De façon générale, il y a autant de plasticités phénotypiques que d’associations caractère phénotypique/variable environnementale. La plasticité phénotypique résume en une seule valeur toute la dynamique d’une réponse particulière. Si en sélection naturelle une plasticité élevée parait constituer un avantage, ce n’est pas aussi évident en sélection artificielle
Phenotypic plasticity is the ability of individual genotypes to adjust to environmental variation. In this thesis we used larch annual ring traits to estimate phenotypic plasticity at two-time scales: between years (chap. 1, inter-annual phenotypic plasticity) and within years (chap. 2, intra-annual phenotypic plasticity). In chap. 1 we analyzed annual rings of European larches distributed in four plots along a natural elevational gradient near Briançon, in the French Alps. The phenotypic plasticity of radial growth and latewood density as a function of maximum temperature tends to be negative at low elevation (1350 m) and distinctly positive at high elevations (2300 m), where European larch seems to react favorably to temperature increase. No elevation trend emerges for earlywood density, which mostly exhibits negative or null phenotypic plasticity. The phenotypic plasticity of mean ring density is intermediate between that of earlywood and of latewood density. In chap. 2 we used intra-annual radial growth curves recorded with automatic point dendrometers during four successive growing seasons in an experimental trial combiningseveral water regimes and three species of larch. From such curves we obtainedphenotypic plasticity variables for radial growth and the dynamics of water in the trunk as a function of several climatic variables. All phenotypic plasticity variables and all environmental conditions combined, hybrid larch is a little more plastic than Japanese larchand much more than European larch, which reflects its ability to quickly and efficiently replenish and use his water reserve. We hypothesize that this contributes to its greater vigor.In general, there are as many types of plasticity as there are combinations of phenotypic traits and environmental variable. Phenotypic plasticity summarizes in a single value all the dynamics of a particular response. While in natural selection a high plasticity seems to be an advantage, it is not so evident in artificial selection

The role of fire in determining the structure and composition of many forested ecosystems is well documented (e.g. North American boreal forests; piñon-juniper woodlands of the western US). Fire is also believed to be important in temperate forests of eastern North America, but the processes acting here are less clear, particularly in xerophytic forests dominated by yellow pine (Pinus, subgenus Diploxylon Koehne) and oak (Quercus L.). In this study, I use dendroecological techniques to investigate fire history and vegetation dynamics of mixed pine-oak forests in the central Appalachian Mountains of Virginia. The study addresses three objectives: (1) develop a lengthy fire chronology to document fire history beginning in the late presettlement era and extending throughout the period of European settlement, industrialization and modern fire exclusion; (2) explore fire-climate relationships; and (3) investigate vegetation dynamics in relation to fire occurrence. The study was conducted on three study sites within the George Washington National Forest. I used fire-scarred cross-sections from yellow pine trees to document fire history. Fire-climate relationships were investigated for each study site individually and all sites combined using superposed epoch analysis (SEA). Fire-history information was coupled with dendroecological data on age structure to explore stand development in relation to fire occurrence. Results of fire history analysis reveal a long history of frequent fire with little temporal variation despite changes in land use history. Mean fire intervals (MFI) ranged from 3.7–17.4 years. The most important change in the fire regime was the initiation of fire suppression in the early twentieth century. Results of SEA show that periodic droughts may be important drivers of fire activity. Drought the year of fire was important at two of the three study sites and when all sites were combined. Results of age structure indicate that vegetation development was clearly influenced by fire. Frequent burning maintained populations of yellow pine throughout the period of study until fire suppression allowed fire-sensitive hardwood trees and shrubs to establish. It is clear from this study that continued fire suppression will likely result in fire-tolerant pines and oaks being replaced by more mesophytic trees and shrubs.

The main objectives of this investigation were to determine the impact of climate on mountain birch (Betula pubecens ssp. czerepanovii (Orlova)) growth and to develop a regional chronology of autumnal moth outbreaks. To accomplish the objective, cores of mountain birch were taken from 21 sites in Norrbotten, Sweden. Tree-ring chronologies were developed for each site. Climatic influences were determined by correlating ring widths to climatic variables (average monthly temperature, average monthly precipitation and NAO). Outbreaks were recovered from the ring width indices using the non-host method with Scots pine (Pinus sylvestris (L.)) as the non-host. This method removes the climatic influence on growth to enhance other factors. Patterns of synchrony and regional outbreaks were detected using regression and cluster analysis techniques. The primary climatic influences on the tree ring growth of mountain birch are June and July temperatures; precipitation during October is of secondary importance. Climate explained 46% of yearly tree ring width variation. Outbreaks of the autumnal moth occur at varying time intervals depending on the scale of study. Intervals between outbreaks on the tree level are twice as long as at the plot level. On the regional scale plots within the same valley had more similar outbreak intervals and magnitudes of outbreaks. Elevation is a driver in determining the length of outbreaks and length between outbreaks. The percent monocormicity of a plot is also a determining factor of the length between outbreaks. This study is the first regional scale study on climate and outbreaks of the autumnal moth on mountain birch. The results complement research being conducted on autumnal moth larval densities and will help in modeling and assessing the effects of outbreaks with increasing climatic change.

While wildfire is globally most common in the savanna-grassland ecotone, the flammability of coastal temperate rainforests is considered low and little is known regarding historic fire activity. Reconstructing historical fire activity typically requires dendrochronological records from fire-scarred trees and post-fire cohorts, but this type of information is rare in perhumid temperate rainforests, which are dominated by dense fuels with high year-round moisture content. I reconstructed historic fire activity using fire scars, tree rings, soil charcoal, and remote sensing techniques in a 2000 km2 island group located within the Hakai Lúxvbálís Conservancy on the coastal margin of central British Columbia. I broadly assessed 13,000 years of fire activity with charcoal deposited in soils, and reconstructed late Holocene fire events with a 700-year chronology built from living fire-scarred trees and stand establishment data. I used a weight of evidence approach to hypothesize the origins of fires and whether First Nations intentionally utilized fire for resource management. Low-severity fires occurred most frequently in forests surrounding former First Nations habitation sites, and lightning strikes do not occur often enough to explain the observed temporal or spatial patterns of fire activity in the study area. Low-severity fires occurred approximately every 39 years, and were 25 times more likely to occur than previously estimated. Fires influenced the composition and structure of vegetation by creating a mosaic of vegetation types in different stages of succession, and thus increased the abundance of culturally important food plants. Fire events have not occurred in the study area since 1893, which also coincides with the reduction of First Nations activities in their traditional territories. My data are consistent with the hypothesis that humans intentionally used fire to manage resources, though further research and ethnographic data collected elsewhere in the region is required to corroborate these findings. Ecological legacies of historic fires remain visible on the present day landscape, and by reconstructing the historic range of fire cycle variability we gain a better understanding of human-driven fire activity and the abrupt changes that occurred in the 20th century.
Graduate

The western spruce budworm (Choristoneura occidentalis Freeman) is the most widespread and destructive defoliator of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) forests in British Columbia. Over the past two decades, western spruce budworm outbreaks have been sustained and widespread in the interior of British Columbia, leaving the forest industry and many forest-dependent communities increasingly vulnerable to the economic consequences of these outbreaks. While a great deal is known about the impact of western spruce budworm outbreaks on tree growth and form, substantial knowledge gaps remain as to the historic variability of western spruce budworm outbreaks and the consequences of defoliation on fundamental characteristics such as wood structure. This research focused on describing historic and contemporary western spruce budworm outbreaks across multiple spatial and temporal scales in south-central British Columbia using dendrochronology and wood anatomy techniques. Outbreak histories over the past 435 years were reconstructed using a network of tree-ring chronologies from central British Columbia, revealing that 12 western spruce budworm outbreaks have occurred since the early 1600s, with a mean return interval of 30 years. Further, the research illustrates that outbreaks observed over the last 40 years are not unprecedented, which does not support the perception that western spruce budworm is moving northward into central British Columbia. To evaluate the effects of a single western spruce budworm outbreak on the anatomical characteristics of Douglas-fir stemwood, tree ring data was collected from permanent sample plots that sustained both periodic and chronic western spruce budworm feeding. In mature even-aged stands of Douglas-fir, a documented outbreak occurred from 1976 to 1980 in the coastal transition zone of southern British Columbia. Based on microscopic wood anatomical measurements it was shown that the tree rings formed during this outbreak had significantly lower percentages of latewood, reduced mean cell wall thickness and smaller radial cell diameters relative to wood formed during periods without budworm feeding. Western spruce budworm defoliation temporarily modified cellular characteristics, which has implications for wood quality. In uneven-aged stands of mature Douglas-fir, located in the xeric southern interior of British Columbia, there has been a sustained western spruce budworm outbreak since 1997. Tree rings formed during this outbreak had progressively larger earlywood lumen area and radial cell diameter, reduced latewood cell wall thickness, latewood radial cell diameters, and lower percent latewood. Mixed-effects models revealed that climatic variables, defoliation severity, defoliation duration, and in limited cases canopy class were the best predictors of xylem features. The severity and duration of western spruce budworm defoliation, as well as site factors that influence moisture conditions effect the degree and direction of anatomical changes in the stemwood of Douglas-fir. This research fills a number of knowledge gaps by providing insights into the temporal and spatial dynamics of western spruce budworm outbreaks in central British Columbia over multiple centuries, and the plasticity of anatomical features in the stemwood of Douglas-fir during discrete western spruce budworm outbreaks. These research findings suggest that Douglas-fir forests are resilient to western spruce budworm outbreaks over space and time.
Graduate