Dissertations / Theses on the topic 'Woody trees'

Phipps showed that the cross-sectional area of successive tree rings in suppressed red maples and chestnut oaks, sampled at three-foot intervals above the base, is approximately constant. I show that this invariance in cross-sectional area is consistent with ring width varying as the inverse square root of ring number and with mean ring diameter and trunk diameter each scaling as the square root of ring number. These results may be useful in formulating growth rules for tree trunks of selected species, under constant environmental conditions, in terms of a single independent variable. For example, if elastic similarity holds, trunk height is proportional to the two-thirds power of trunk diameter. This relation implies that trunk height scales as the cube root of ring number. Thus, trunk height and trunk diameter may, in principle, both be expressed in terms of one independent variable, ring number.

A method for determining the germination dates of trees is based on wood anatomical characteristics and dendrochronology. This procedure requires destructive sampling of the tree for an extensive analysis of the zone between the roots and the trunk of the tree (root/shoot interface). The method is applicable to forest ecology and woody plant life history studies.

The relative weights on individual trees in a biweight site chronology can indicate the consistency of tree growth responses to macroclimate and can be the basis for stratifying trees in climate-growth analyses. This was explored with 45 years of ring-width indices for 200 trees from five even-aged jack pine (Pints banksiana Lamb.) stands. Average individual-tree relative weights were similar, but most trees had at least one transient occurrence of low relative weight. The standard deviations of individual-tree relative weights suggested that some trees had mom variable growth responses than others. The trees were classified by the average and standard deviation of their relative weights, and biweight site chronologies were then calculated for these subgroups. Chronologies derived from trees with low average weights, and from trees with high standard deviation of weights, sometimes appeared to be different from chronologies derived from the remaining trees.

This article describes the analysis of tree-ring collections from standing trees of sixteen species at twenty sites distributed throughout the Italian Peninsula. Visual and numerical crossdating among ring widths allowed the computation of standard and residual tree-ring chronologies. Relationships among chronologies were identified by Spearman's coefficient of rank correlation, using Bonferroni's inequality to adjust significance level. The oldest living tree sampled to date is a 963-year old palebark pine (Pinus leucodermis Ant.) at Parco del Pollino. Individuals more than two centuries old were identified at eleven sites for eight species. The tree-ring network so far consists of twenty-two chronologies for nine species at nineteen sites. Seven conifer species account for ten chronologies and two angiosperm species account for the remaining twelve chronologies. The most represented species is Fagus sylvatica L., with eleven chronologies distributed over the entire peninsula and highly correlated with one another. The order of autoregressive models fitted to the data never exceeded two. In particular, the order of autoregressive models fitted to Fagus sylvatica chronologies decreased with decreasing age of sampled trees. Based on the significant coefficients of rank correlation, residual chronologies of Fagus sylvatica could be separated into northern, central, and southern groups. This points to the existence of broad regions distributed along a latitudinal gradient, corresponding to large-scale climatic regimes over the Italian Peninsula.

During the past 100 years, researchers have investigated the potential of hundreds of tree and shrub species for use in applications of tree-ring research. Although several lists of species known to crossdate have been published, investigated species that do not crossdate are rarely included despite the usefulness of this information for future research. This paper provides a list of the Latin and common names of 573 species that have been investigated in tree-ring research, information on species known to crossdate, and information on species with measurement and/or chronology data in the International Tree-Ring Data Bank. In addition, a measure of the suitability of a species for future tree-ring applications, the Crossdating Index (CDI), is developed and proposed for standard usage.

Dendrochronological problems in dating tropical tree species are responsible for a large gap in global dendroclimatic reconstructions. Study of Cedrela and Juglans in the low-latitude forests of northern Argentina and Bolivia has resulted in development of four chronologies. These genera have good tree-ring characteristics, and statistics indicate that they have good potential for dendroclimatology. Longer series should be obtained from older stands.

The variation in wood density within growth rings was determined from X-ray negative images of wood samples of Gmelina arborea. The within-tree and between-tree comparisons showed that no two growth rings had exactly similar patterns of variation in the radial direction. The proportions of wood in four within-ring density classes were estimated. The variations in the proportions of wood in the four classes with age were nonlinear. On the average, the proportion of low density wood decreased with increasing age, while the proportion of high density wood increased with age. Regression analysis testing different curvilinear models showed that 37 to 99 per cent of the variations in the proportions of wood were associated with variations in age. Maximum and minimum ring density were negatively correlated with dry season rainfall. Variations in the proportion of high density wood and mean ring density were not associated with corresponding variation in dry season rainfall. The proportions of low and high density wood, mean ring density, maximum ring density and minimum ring density were not determined by annual rainfall.

Special sanding films (400 grit to 23 micron) and fine sandpapers (1200-1500 grit) can be used to surface increment cores containing narrow rings (e.g., >50 rings per cm) so that rings are clearly visible for microscopy and photography.

Tree-ring dating was used to develop construction scenarios for two log structures, the Draper and the Fuller buildings. in the Edwards Plateau region of Texas. The Draper building was constructed in 1902-3, and added onto in 1906. The dating of the Fuller building is less certain, but the structure probably was built in the 1860s or 1870s.

The signal strength of a biweight site chronology is properly viewed as an outcome of analysis rather than as a property of the forest-climate system. It can be estimated by the evenness of the empirical weights that are assigned to individual trees. The approach is demonstrated for a 45-year biweight chronology obtained from 40 jack pine (Pinus banksiana Lamb.) trees. The annual evenness of the empirical weights is calculated by indices derived from the Shannon and Simpson diversity indices, and the variances are found by the jackknife procedure. The annual estimates are then averaged to find an overall estimate of biweight signal strength for the 45-year period. These techniques are most useful for determining sample sizes for the biweight procedure, and for comparing different methods of detrending and standardizing data sets prior to applying the biweight mean-value function.

Insect herbivory is a key ecological process which mediates the structure, functioning and maintenance of forests. Studies of insect herbivory in tropical forests typically focus on trees whereas the contributions of other plant types, particularly climbing plants, remains undervalued and under studied. Lianas, or woody climbing plants, are important ecosystem contributors. Per unit basal area, lianas support substantially more leaves than trees and typically comprise 20-40% of the above ground leaf biomass in rainforests. This indicates a likely function in insect herbivory. Little data, however, exists which quantifies the importance of their contribution to overall ecosystem dynamics, particularly in contrast with trees. Information on the contributions of other plant types to herbivory are necessary if we are to fully appreciate the role of lianas in herbivory and understand the ways in which forests and associated processes may shift given anticipated environmental and vegetation changes. This thesis aims to address this knowledge gap and demonstrate the value of lianas in supporting herbivory and associated insect assemblages. I aim to establish the need for a better understanding of liana-supported insect herbivory, quantify the trophic link among different plant types and insects in two contrasting rainforests, and determined the influence of structural and chemical leaf traits. First, I determine the need for liana focussed herbivory research by providing a comprehensive review of the literature. Second, I examine the temporal changes in liana and tree communities over two decades in a 1 ha plot of Australian subtropical rainforest. It is firmly established that lianas are increasing in Neotropical rainforest. In other bioregions, however, the pattern is less clear and derived from few sources. In Australia, where the factors influencing vegetation dynamics may differ, no such studies exist. I found liana abundance and biomass increased substantially from 2005 to 2015 while tree abundance remained stable from 1995 to 2015. Tree biomass also rose considerably, but at approximately half the rate of lianas. Based on the structure of liana and tree communities, I suggest increasing atmospheric CO2 to be the most probable explanatory hypothesis over changes in rainfall or tree mortality. Given the results presented here and other documented increases in liana abundances globally, it is concerning we do not know more about the ecosystem services they provide. Third, theoretical and empirical evidence suggests lianas may be an important food source for phytophagous insects. I address this hypothesis by two methods. First, in a literature-based study I assess the relative use of lianas as host plants for Australian butterflies. Second I make quantitative assessments Insect herbivory is a key ecological process which mediates the structure, functioning and maintenance of forests. Studies of insect herbivory in tropical forests typically focus on trees whereas the contributions of other plant types, particularly climbing plants, remains undervalued and under studied. Lianas, or woody climbing plants, are important ecosystem contributors. Per unit basal area, lianas support substantially more leaves than trees and typically comprise 20-40% of the above ground leaf biomass in rainforests. This indicates a likely function in insect herbivory. Little data, however, exists which quantifies the importance of their contribution to overall ecosystem dynamics, particularly in contrast with trees. Information on the contributions of other plant types to herbivory are necessary if we are to fully appreciate the role of lianas in herbivory and understand the ways in which forests and associated processes may shift given anticipated environmental and vegetation changes. This thesis aims to address this knowledge gap and demonstrate the value of lianas in supporting herbivory and associated insect assemblages. I aim to establish the need for a better understanding of liana-supported insect herbivory, quantify the trophic link among different plant types and insects in two contrasting rainforests, and determined the influence of structural and chemical leaf traits. First, I determine the need for liana focussed herbivory research by providing a comprehensive review of the literature. Second, I examine the temporal changes in liana and tree communities over two decades in a 1 ha plot of Australian subtropical rainforest. It is firmly established that lianas are increasing in Neotropical rainforest. In other bioregions, however, the pattern is less clear and derived from few sources. In Australia, where the factors influencing vegetation dynamics may differ, no such studies exist. I found liana abundance and biomass increased substantially from 2005 to 2015 while tree abundance remained stable from 1995 to 2015. Tree biomass also rose considerably, but at approximately half the rate of lianas. Based on the structure of liana and tree communities, I suggest increasing atmospheric CO2 to be the most probable explanatory hypothesis over changes in rainfall or tree mortality. Given the results presented here and other documented increases in liana abundances globally, it is concerning we do not know more about the ecosystem services they provide. Third, theoretical and empirical evidence suggests lianas may be an important food source for phytophagous insects. I address this hypothesis by two methods. First, in a literature-based study I assess the relative use of lianas as host plants for Australian butterflies. Second I make quantitative assessments Insect herbivory is a key ecological process which mediates the structure, functioning and maintenance of forests. Studies of insect herbivory in tropical forests typically focus on trees whereas the contributions of other plant types, particularly climbing plants, remains undervalued and under studied. Lianas, or woody climbing plants, are important ecosystem contributors. Per unit basal area, lianas support substantially more leaves than trees and typically comprise 20-40% of the above ground leaf biomass in rainforests. This indicates a likely function in insect herbivory. Little data, however, exists which quantifies the importance of their contribution to overall ecosystem dynamics, particularly in contrast with trees. Information on the contributions of other plant types to herbivory are necessary if we are to fully appreciate the role of lianas in herbivory and understand the ways in which forests and associated processes may shift given anticipated environmental and vegetation changes. This thesis aims to address this knowledge gap and demonstrate the value of lianas in supporting herbivory and associated insect assemblages. I aim to establish the need for a better understanding of liana-supported insect herbivory, quantify the trophic link among different plant types and insects in two contrasting rainforests, and determined the influence of structural and chemical leaf traits. First, I determine the need for liana focussed herbivory research by providing a comprehensive review of the literature. Second, I examine the temporal changes in liana and tree communities over two decades in a 1 ha plot of Australian subtropical rainforest. It is firmly established that lianas are increasing in Neotropical rainforest. In other bioregions, however, the pattern is less clear and derived from few sources. In Australia, where the factors influencing vegetation dynamics may differ, no such studies exist. I found liana abundance and biomass increased substantially from 2005 to 2015 while tree abundance remained stable from 1995 to 2015. Tree biomass also rose considerably, but at approximately half the rate of lianas. Based on the structure of liana and tree communities, I suggest increasing atmospheric CO2 to be the most probable explanatory hypothesis over changes in rainfall or tree mortality. Given the results presented here and other documented increases in liana abundances globally, it is concerning we do not know more about the ecosystem services they provide. Third, theoretical and empirical evidence suggests lianas may be an important food source for phytophagous insects. I address this hypothesis by two methods. First, in a literature-based study I assess the relative use of lianas as host plants for Australian butterflies. Second I make quantitative assessments of herbivore damage in the canopy of a tropical Chinese rainforest and the understory of a subtropical Australian rainforest based on new, primary data. Lianas, and vines alike, are hypothesised to be important food plants for butterflies. This speculation, however, has never been formally tested. Based on available food plant information of Australian butterflies, I found lianas to be an important food source for butterfly caterpillars in rainforests and their use as host plants to be greater than what simple plant diversity would predict. Interestingly, butterflies feeding on climbing plants had significantly greater incidences of monophagy than those feeding on trees. The patterns of host plant use and specialisation on trees and lianas are similar to those found in phytophagous rainforest beetles elsewhere. If lianas support greater diversity and abundances of foliar feeding insects than trees, we would expect this to be reflected by asymmetrical incidences of herbivore damage across the two plant types. I found no overall significant difference across plant types in neither the canopy of a tropical Chinese rainforest or the understory of a subtropical Australian rainforest, providing further support for this hypothesis. I did however observe that; 1) lianas influence their host’s leaf traits, most likely through inputs of nitrogen rich leaf litter around the base of their hosts, 2) under drought conditions lianas may reduce the amount of herbivory occurring on their host trees, and 3) leaf traits important for predicting herbivory are not consistent across plant types. Through the combination of studies, I have shown that lianas are an important food source for herbivorous insects at least as much so as trees. The results of this thesis have helped close the knowledge gap in our understanding of herbivory and demonstrate the importance of lianas in supporting insect assemblages. Without understanding the contributions of other plant types to herbivory (and the associated insect faunas they support) we are unable to make accurate models and predictions about their future. Given lianas are increasing in many tropical rainforests, including those studied here, it is concerning that not more is known about their contributions to herbivory and their relationships with the insect herbivores they support – this thesis goes part way to allay this concern.<br>Thesis (PhD Doctorate)<br>Doctor of Philosophy (PhD)<br>School of Environment and Sc<br>Science, Environment, Engineering and Technology<br>Full Text

Analysis of the relationship between ring-width indices of pedunculate oaks (Quercus robur L.) in the Niepotomice Forest with average monthly air temperatures (1826-1980) and total monthly precipitation (1881-1985) in Cracow revealed a strict relationship between tree -growth and the precipitation of June-July, May-July, and June-August. These relationships are described by a high percentage of agreement, at or around 70 %, and coefficients of correlation (rx) of 0.40 (June-July), 0.36 (May-July) and 0.30 (June-August). The group of 10 oaks with the highest coefficients between growth and precipitation yielded still higher correlations: 0.50, 0.50, and 0.41, respectively. High total monthly precipitation in June and July favors radial growth, while low precipitation reduces radial growth. The influence of air temperature on oak ring-width indices is less significant. The highest positive correlation occurs for January to April of the preceding year. Correlations for the years of radial growth have values close to or below (June) zero except for August.

Giant sequoia was one of the first species that A. E. Douglass examined in his pioneering tree- ring research. Recent attention to sequoia, stimulated by fire history studies in sequoia groves, has resulted in new ring-width chronologies based on both recently collected tree-ring material and Douglass' original samples. The development and characteristics of four new multimillennial sequoia chronologies are described here. Three of these chronologies are based on tree-ring series from individual sites: Camp Six (347 B.C. to A.D. 1989), Mountain Home (1094 B.C. to A.D. 1989), and Giant Forest (1235 B.C. to A.D. 1988). The fourth is a composite chronology (1235 B.C. to A.D. 1989) that includes radii from the other three chronologies. Sequoia ring series are generally complacent with occasional narrow rings ("signature years"). Ring-width standardization was complicated by growth releases, many of which are known to have been caused by fires. Such growth releases confuse climatic interpretation of low-frequency signals in the time series. Ring- width series were detrended with cubic splines with 50% frequency response function at 40 years to de-emphasize low-frequency variation and were fit with autoregressive time series models to remove persistence. The resulting prewhitened chronologies contain primarily a high frequency climate signal and are useful for assessing the past occurrence of extreme drought events and for dating applications. The dating chronology originally developed by Douglass is confirmed and the annual nature of giant sequoia tree rings unequivocally verified.

Hypotheses about the causes of the growth and decline of the Chacoan regional interaction system in the southwestern United States between A.D. 900 and 1200 are evaluated against tree-ring evidence and the results of an empirical model (PRECON) that computes the statistical relationships between climate and ring-width indices during the 20th century and applies the results to hypothesized precipitation or temperature changes. The statistical responses of 23 indexed conifer ring-width chronologies from New Mexico and Colorado to variations in monthly temperature and precipitation were calculated. Simulated decreases in prior autumn-winter precipitation markedly reduced ring widths, while decreased current summer precipitation was less effective, sometimes reducing ring width or having little effect. Decreased prior winter temperature slightly reduced ring width, while decreased growing season temperature usually increased or did not effect ring widths. Evaluated in terms of these results, the Chaco Canyon area tree-ring record (1) indicates that favorable climatic conditions in the 10th, 11th, and early 12th centuries fostered the growth of the Chacoan system, (2) shows that dry autumn-winter and summer conditions in the middle 1100s contributed to the downfall of the system, (3) does not support the proposition that centuries-long climatic fluctuations evident in southwestern Colorado affected Chaco Canyon, (4) does not support the idea of shifts from summer-to winter-dominant precipitation regimes, and (5) contributes little to assessing the role of anthropogenic environmental change in the collapse of the Chacoan system.

Stormwater management basins (SWMB) are used to mitigate urban runoff. The Virginia Department of Transportation relies on dry detention basins planted with mowed turfgrass. However, these basins often retain water; resulting in cattail (Typha spp.) and tree colonization. Managing agencies request cattail eradication and trees are also removed. However, if trees were allowed to remain they could alter basin dynamics, making conditions unsuitable for cattails. <p> In a greenhouse study we tested the impact of three shade (heavy, medium, full sun) and soil moisture (dry, moist, flooded) treatments on cattail growth. After two months, cattail biomass indicated a strong interaction between soil moisture and shade (p<.0001). Increases in shade and reductions in soil moisture resulted in decreased biomass and rhizome length. Heavy shade and dry soil produced the most reductions in cattail growth (95% less biomass, 83% smaller rhizomes than cattails in full sun and flooded soil). However, considerable growth reductions still occurred in medium shade and moist soil (66% for biomass and 74% for rhizome lengths). <p> In a field study in four unmaintained SWMB in Virginia, environmental data (litter layer, water table, soil organic matter, etc.) and vegetation composition (cattail and other herbaceous biomass, and woody vegetation influence index) were collected from 100, 0.25-m2 plots. Principal component analysis indicated cattails and trees occupy opposing environmental spaces. Water table is most strongly correlated to cattail biomass. While these results suggest trees could eliminate cattails from SWMB, more research is needed to determine the long-term impacts of trees on basin function.<br>Master of Science

Ten ring-width based chronologies from Nepal are described and the prospects for further dendroclimatic work there reviewed briefly. The initial results are encouraging, and more intensive subregional sampling is called for. All the cores examined showed distinct annual rings, and there was little evidence of double or missing rings, except juniper at some sites and in some Pinus roxburghii trees. Difficulty was encountered in dating Pinus wallichiana and Cupressus dumosa. Individual site chronologies of Cedros deodora, P. roxburghii and P. wallichiana were particularly promising, and of high elevation Abies spectabilis moderately so. Densitometric data are likely to be more useful for this species. The paucity of meteorological data in Nepal represents an obstacle to further dendroclimatic work there.

The relationships between the tree-rings of the white fir (Abies alba Mill.) and climate in the French internal Alps are indicated by correlation functions. This fir shows an accurate response to climate as well as long term persistence for at least six years (MS =0.18, R1 =0.65, and R6= 0.27). Its growth is strongly influenced by the previous year's climate, especially by prior August rainfall, which enhances ring size, or by high temperatures, which show the opposite effect. The most critical period extends from prior July to prior September. This species responds positively to warm temperature from current January to April, followed by rainfall in May and June, which leads to a longer growth period. A favorable water balance seems to be decisive. Abies alba can be affected by frost and seems to prefer a low thermal amplitude as demonstrated by the analysis of the extreme temperature data. Moreover, even a few days of excessive heat can reduce its growth.

Growing landscape trees in containers is a common practice in the nursery industry. In the southeastern United States, pine bark is often used as a container substrate, and two common amendments to pine bark are lime and micronutrients. In this study, three experiments were conducted to determine the effect of these amendments on the growth of a wide range of landscape tree species grown in pine bark. In the first experiment, nine species of landscape trees [Acer palmatum (Japanese maple), Acer saccharum (sugar maple), Cercis canadensis (redbud), Cornus florida (flowering dogwood), Cornus kousa (kousa dogwood), Koelreuteria paniculata (golden-rain tree), Magnolia x soulangiana (magnolia), Nyssa sylvatica (blackgum), and Quercus palustris (pin oak)] were grown from seed in two pine barks: pH 4.7 (low) and 5.1 (high). Preplant amendment treatments to each pine bark (Pinus taeda) were: with or without dolomitic limestone (3.57 kg.m-3) and with or without micronutrients (0.9 kg.m-3, Micromaxâ ¢). The same experiment was repeated using Koelreuteria paniculata and Quercus palustris, the same lime and micronutrient treatments, and two pine barks: pH 5.1 (low) and 5.8 (high). In both experiments, micronutrients increased shoot dry mass and height for all species, while lime decreased shoot dry mass and height for all species. Effect of bark type in the first experiment was variable, while shoot dry mass and height were highest in the low pH bark when the experiment was repeated. Substrate solution element concentrations increased when micronutrients were added, decreased when lime was added, and in general, concentrations were higher in low pH bark than in high pH bark. In the third experiment, Koelreuteria paniculata was grown from seed in pine bark amended with 0, 1.2, 2.4, or 3.6 kg.m-3 dolomitic limestone and 0 or 0.9 kg.m-3 micronutrients (Micromaxâ ¢). Initial pH for each lime rate was 4.0, 4.5, 5.0, and 5.5, respectively. Adding micronutrients increased shoot dry mass and height. Lime increased growth only at the 1.2 kg.m-3 rate. In general, substrate solution element concentrations increased when micronutrients were added and decreased when lime was added. In all three experiments, adding micronutrients was necessary regardless of pine bark pH, while adding lime was not necessary.<br>Master of Science

Annual rings of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, which sustained 1 year of defoliation by the western false hemlock looper, Nepytia freemanii Munroe (Lepidoptera: Geometridae), showed a period of decrease in breast height ring width starting in the year that followed the damage. The magnitude of the decrease was related to the degree of defoliation: there was no ring width decrease on trees that were 0-10% defoliated; the decrease became progressively more noticeable in trees which sustained increasingly higher defoliation; and it was maximum in trees which sustained 91-100% defoliation. This period of reduction lasted 1 to 5 years and was followed by a period of above-normal growth which was related to defoliation in a similar manner: it was absent in trees 0-10% defoliated and maximum in the 91-100% tree defoliation class. Increase in defoliation caused a significant increase in index standard deviation, autocorrelation and mean sensitivity.

Avui dia a Espanya i en moltes regions del món s'enfronten al problema d'escassetat d'aigua i la disminució de les seves ofertes. D'altra banda, les projeccions dels models climàtics preveuen que l'escassetat d'aigua es convertirà en un dels problemes més importants en moltes zones del món. Aquest seriòs problema fa que sigui urgent millorar l’eficiència en l’ús d’aigua. Considerant aquest aspecte, l'objectiu general d'aquesta tesis ha estat millorar l'eficiència del reg mitjançant la utilització de nous protocols de reg en dos espècies d’arbres, cirerers (Prunus avium) i de platan d’ombra (Platanus x hispanica) per a produir fusta. Mitjançant l'aplicació de diferents estratègies de reg deficitari basades en mesures de la màxima contracció diària del diámetre del tronc (MCD) combinat amb la mesura de l'estat de l'aigua al sòl. Els assajos van ser realitzats els anys 2009 i 2010, en un hivernacle (primer capítol) i en camp obert (segon i tercer capítol) a les instal•lacions de l'IRTA a Torre Marimon. Els objectius del primer capítol van ser avaluar si la MCD és un bon indicador de l’estat hídric del cirerer a partir de les relacions amb altres indicadors fisiològics i ambientals; així mateix, es va obtenir un valor llindar d'aquesta variable per a utilitzar-lo en la programació de reg. Com s'esperava els arbres ben regats i els arbres estressats van presentar diferències significatives en les variables fisiològiques: conductància estomàtica foliar (gs), potencial hídric foliar de migdia (md) i el flux de saba diari (Qd); el potencial matricial del substrat (s) va disminuir a valors de - 33 kPa i el corresponent valor de MCD va ser aproximadament de 0.30 mm. Aquests valors són considerats llindars potencials per a planificar el reg cirerers joves. Aquests valors corresponen a un md de -2.3 MPa i una gs de 50 mmol m-2 s-1, els quals indiquen estrès sever. En la part B del primer capítol, l'objectiu era explorar si la sequera afecta el patró diàri i horari dels dos indicadors de l’estat hídric mesurats en continu com son la variació del diàmetre del tronc i el flux de saba. Els arbres estresats mostren un increment significatiu de la MCD i un decrement del flux de saba respecte als arbres ben regats. La MCD és més sensible que el SF diàri front l'estrès per sequera, principalment a causa de la variabilitat més gran del SF entre arbres. En els cicles diàris, la variació del diàmetre del tronc i el flux de saba estan relacionats per un bucle que es comporta diferent quan estàn ben regats o estan estressats. La variació del pendent de la relació entre les dues varibles entre les 8 i les 16 hores en situacions de sequera pot ser un indicador d’estrés. Els objectius del segon capítol van ser intentar millorar la gestió de reg en arbres, cirerer i plàtan d’ombra, mitjançant la implantació de nous protocols de reg deficitari regulat (RDImds) basat en el valor absolut de la MCD i el potencial matricial del sòl (s), també es va combinar amb l’us d’aigua regenerada en cirerers . Els resultats indiquen que no va haver cap efecte negatiu associat amb l’aplicació del tractament RDI en el creixement en diàmetre, alçada i cobertura verda relativa, ni en la conductància estomàtica en ambdues especies. La qualitat d’aigua de reg tampoc va afectar al creixement dels cirerers El tractament RDImds ha estalviat aigua sense cap efecte negatiu sobre el creixement de l'arbre, amb el mateix comportament quan s’ha regat amb aigua regenerada o aigua de pou. El protocol aplicat en 2009 podria ser recomanat per a cirerers joves, i el protocol aplicat en 2010 podria ser recomanat per als plàtans. En el tercer capítol, l'objectiu va ser evaluar un protocol de programació de reg basat en el s i la señal de laMCD (MCDRDI/MCD100%Etc) en cirerer i en plàtan d’ombra. Els resultats van indicar que tractaments de RDI basats en la señal de MCD no van tenir efecte negatiu en els indicadors de creixement dels arbres, ni en la MCD ni en la gs. El tractament RDIsenyal va estalviar el 20-30% de l'aigua en les dues espècies. Així com en el tractament RDImds, el protocol aplicat en 2009 es podria recomanar per als cirerers joves i el protocol utilitzat en 2010 es podria recomanar per a plàtans d’ombra. Aquest darrer tractament té la desventatja que es necessita un control, però a la vegada evita els problemes de la influència de les condicions ambientals en la MCD del tractament RDImds.<br>Hoy en día en España y en muchas regiones del mundo se enfrentan al problema de la escasez de agua y la disminución de sus suministros. Por otra parte, las proyecciones de los modelos climáticos preveen que la escasez de agua se convertirá en uno de los problemas más importantes en muchas zonas del mundo. La gravedad de problema hace que sea necesario mejorar la eficiencia del uso del agua. Considerando lo anterior, el objetivo general de esta tesis es mejorar la eficiencia del riego mediante la utilización de nuevos protocolos de gestión de riego en dos especies de árboles: cerezos (Prunus avium) y plátano de sombra (Platanus x hispanica) para producir madera. Mediante la aplicación de diferente estrategias de riego deficitario basadas en las medidas de la máxima contracción diaria del tronco (MCD) combinado con la medida del estado hídrico del suelo. Los ensayos se realizaron los años 2009 y 2010, en un invernadero (primer capítulo) y en campo (segundo y tercer capítulo) en las instalaciones del IRTA en Torre Marimon. Los objetivos del primer capítulo fueron evaluar si la MCD es un buen indicador del estado hídrico del cerezo a partir de las relaciones con otros indicadores fisiológicos y ambientales; asimismo, se obtuvo un valor umbral de esta variable para utilizarlo en la programación del riego Como se esperaba, los árboles bien regados y los estresados presentaron diferencias significativas en todas las variables fisiológicas: conductancia estomática (gs), potencial hídrico de la hoja al mediodía ( md) y flujo de savia diario (Qd); el potencial matricial del substrato ( s) disminuyó hasta -33, y el correspondiente valor de MCD fue aproximadamente 0.30 mm. Estos valores se consideran umbrales potenciales para la programación del riego de árboles jóvenes de cerezos. Estos valores se corresponden a un -2 -1 md de -2.3 MPa y una gs de 50mmol m s , los cuales indican estrés hídrico severo. En la parte B del primer capítulo B, el objetivo fue explorar si la sequía afecta al patrón diario y horario de dos indicadores continuos del estado hídrico como son la variación del diámetro del tronco y el flujo de savia. Los árboles estresados mostraron un incremento significativo de la MCD y un decremento del SF diario respecto a los bien regados. La MCD es más sensible a la sequía que el SF diario, debido principalmente a la mayor variabilidad entre árboles del segundo. En los ciclos diarios, la variación del diámetro del tronco y el flujo de savia horario están relacionados por un bucle que se comporta diferente cuando está regado o estresado. La variación de la pendiente de la relación entre las dos variables entre las 8 y las 16 horas en situaciones de sequía puede ser un indicador de estrés. Los objetivos del segundo capítulo fueron intentar mejorar la gestión del riego en árboles, cerezo y plátano de sombra mediante la implantación de nuevos protocolos de riego deficitario regulado basados en el valor absoluto de MCD (RDImds) y el potencial matricial de suelo ( s), también se combinó con el uso de agua regenerada en cerezos. Los resultados indicaron que no hubo ningún efecto negativo relacionado con los tratamientos de RDI en el crecimiento en diámetro y altura del tronco ni en la cobertura verde, ni en la conductancia estomática en ambas especies. El tratamiento RDImds ha ahorrado agua sin ningún efecto en el crecimiento de los árboles, con el mismo comportamiento cuando se ha regado con agua regenerada o agua de pozo. El protocolo aplicado en 2009 podría ser recomendado para cerezos jóvenes, y el protocolo aplicado en 2010 podría recomendarse para plátanos. En el tercer capítulo, el objetivo fue evaluar un protocolo de riego basado en el s y la señal de la MCD (MCDRDI/MCD100%Etc). Los resultados indicaron que tratamientos de RDIseñal no tuvieron ningún efecto negativo sobre los indicadores de crecimiento de los árboles ni en la MCD ni en la gs. El tratamiento RDIseñal ahorró un 20 - 30% de agua en las dos especies. Així com en el tractament RDImds, el protocolo aplicado en 2009 se podría recomendar para cerezos jóvenes y el protocolo utilizado en 2010 se podría recomendar para plátanos. Este último tratamiento tiene la desventaja que necesita un control, pero a su vez evita los problemas de la influencia de las condiciones ambientales en la MCD del tratamiento RDImds.<br>Nowadays in Spain and many regions in the world face the problem of water scarcity and decreasing of its supplies. Moreover, climatic model projected that water scarcity will become one of the most important problems in many areas of the world. This serious problem supposes an urgent need to improve water use efficiency. Considering this problems, the general objective of this work was to improve irrigation efficiency by using new irrigation management protocol in two different species cherry trees (Prunus avium) and plane trees (Platanus x hispanica) for timber production. By applying different deficit irrigation strategies, based on the dendrometry measurements and other plant based water status indicators combined by soil water status measurements. The essays were conducted in 2009 and 2010; the first parts were conducted in one greenhouse and the second and third parts in the open field at IRTA Torre Marimon facilities. The objectives of the first chapter were to evaluate if MDS is a reliable indicator of cherry plants water status through its relationship with physiological and environmental variables; moreover, to study from these relationships the possibility of derivation a threshold value of MDS that indicated maximum water stress level in order to use it for irrigation scheduling. As expected well irrigated and stressed trees presented significant differences in all physiological variables: stomatal conductance (gs), midday leaf water potential ( md) and daily sap flow (Qd); substrate water potential ( s) decreased till -33kPa and the corresponding MDS value about 0.30 mm. Those values could be considered potential threshold for irrigation scheduling of young cherry trees. Those values corresponded to md of -2.3 MPa and gs of 50 mmol m-2 s-1, indicative of severe water stress. In part B of this chapter, the objective was to explore if drought affected the daily and hourly pattern of two continuous indicators of water status, trunk diameter variation and sap flow. Stressed trees showed a significant MDS increase and SF decrease respect to irrigated trees. MDS was more sensitive than SF in front of drought stress, mainly due to the higher variability of SF from tree to tree. In the daily cycle values, trunk diameter variation and sap flow were related to each other via a loop that differs according to tree water status. The change in the slope of the relationship between the two varibles between 8 and 16 hours in drought conditions can be an indicator of stress. The aims of the second chapter were to improve managing irrigation in woody trees, cherry and plane tree, by applying a regulate deficit irrigation protocols based on the absolute value of MDS (RDImds) and soil water potential ( s), combined by reclaimed water in cherry trees. Results indicated no negative effect related with RDI treatments was noticed on cherry or plane trees growth as no any significant differences was noticed in trunk diameter growth rate (TGR), height and relative green cover (RGC)neither in stomatal conductance in both species. Water quality neither affected the grothw of cherry trees. The RDImds treatment combined with s saved water without any negative effect on tree growth, with the same behavior when irrigated with reclaimed water or well water. The protocol applied in 2009 would be recommended for young cherry trees, and the protocol applied in 2010 would be recommended for plane trees. In the third chapter, the objective was to evaluate an irrigation scheduling protocol based on the information obtained from soil status s and MDS signal (MDSRDI/MDS100%Etc) as precision tools for automated adjustment of deficit irrigation in cherry and plane tree. Results indicated that RDIsignal and s protocols had no negative effect on tree growth indicators TGR and RGC; also no clear differences were noticed between well irrigated and RDIsignal trees in MDS and gs. Our irrigation scheduling protocol based on MDSsignal and s can be considered a valid protocol for schedule irrigation in woody trees as it helped us to save about 20- 30% of water in both species without any negative effect on the trees growth. As well as in the treatment RDImds, the protocol applied in 2009 could recommend for young cherry and protocol used in 2010 could recommend bananas for shade. The latter treatment has disadvantage it takes control, yet avoid the problems of the influence of environmental conditions on MCD treatment RDImds.

Ginn Woods, a 161 acre tract of woodlands located in northern Delaware County, contains one of the largest remaining sections of old growth forest in East Central Indiana. Located approximately 15 miles north of Muncie, it has been regularly used by Ball State students and faculty for education and research for over 60 years. Despite this frequent use, little formal botanical exploration has been published. This study presents a comprehensive inventory of the vascular flora found in the woods and documents the composition and sizeclass distribution of the canopy tree species. The 370 species represent 237 genera and 94 families based on family classification by Gleason and Cronquist (1991). A total of 123 species were recorded for the first time in Delaware County. Of the 370 species listed, 56 or 15.1 % are non-native or naturalized species, thus indicating that the native species are dominant. The overstory canopy species are typical of a beech-maple woods with Acer saccharum and Fagus grandifolia as overallco-dominant species. However the importance of Fagus grandifolia varies in the sections known as North, South and Nixon Woods. With the fragmentation of regional ecosystems into isolated forest systems by urbanization and agricultural development, the maintenance and preservation of original communities becomes more difficult. Ginn Woods is one of the few remaining remanents of old growth forests in East Central Indiana and serves as an important reserve of the native flora of this area. The inventory and overstory tree species analysis provided by this study establishes important baseline data to which future studies can be compared.Ball State UniversityMuncie, IN 47306<br>Department of Biology

<p>Worldwide amphibians and reptiles are declining with habitat fragmentation and destruction as the primary cause. Riparian areas are important for the herpetofauna, but as land is converted to agriculture or harvested for timber the areas are diminishing. The aim of this study was to examine amphibian and reptile abundance in relation to distance from water and in relation to habitat characteristics, foremost per cent deciduous trees. The survey was conducted during spring at six different locations, with continuous forest along streams or rivers, outside of Karlstad, Sweden. Animals were searched along four lines parallel to the water and each study area was visited five times. Statistical analyses were made for grass snake (<em>Natrix natrix</em>), common lizard (<em>Lacerta vivipara</em>) and frogs with joined data of common frog (<em>Rana temporaria</em>) and moor frog (<em>R. arvalis</em>). As expected both reptiles were positively correlated with per cent deciduous trees, with the strongest significance for the common lizard. For grass snake there was also a difference between survey periods, which might reflect the importance of weather. Frogs revealed no trends to trees, but there was a significant difference for habitat characteristics like amount woody debris and per cent bare ground. None of the species were correlated with distance from water which was surprising, especially for the frogs which is more dependent on water than the reptiles. Grass snakes hunt in the water, but the common lizard has no such associations to the water, yet the latter did reveal a slight trend towards being more numerous closer to the water. The causes behind lacking correlation to distance from water may be many, but water characteristics seem very important. Many amphibians prefer warm and calm ponds over running water that in general are colder and likely to inhabit more predators. It was assumed that the amphibians breed in the streams or rivers, but it is possible that other water bodies may have served as breeding sites, which mean the starting point was incorrect.</p>

Urbanization has destroyed and fragmented previously large areas of natural habitat. Small remnants that still exist in numerous cities will be unable to sustain many viable wild plant populations if they do not expand into the surrounding urban matrix. Residential gardens surrounding such remnants, and which form a significant component of urban green space in many cities, could play a role in redressing this problem. Riccarton Bush, a 7.8 hectare forest remnant, and its surrounding suburban residential area, in Christchurch, New Zealand, is a good example. Over 125 years the reported number of native vascular plants in the bush has declined by a third. My study was an attempt to understand: 1) the ecological, social and cultural factors influencing the dispersal and regeneration of 12 native bird-dispersed woody species from Riccarton Bush, into surrounding residential properties; and 2) the potential role residential properties could play in the future of the bush. To examine these diverse factors I adopted an interdisciplinary research approach combining methodologies, concepts and theories from ecology and the social sciences. In a broader context my work was an attempt to demonstrate how urban ecology can further develop and strengthen by adopting and integrating new methodologies, theories and concepts. The ecological component involved recording individuals of the study species found on 90 randomly selected properties within a 1.4 km radius of the bush. Soil samples were also collected from 31 of those properties and placed in a glasshouse and the study species that germinated were recorded. Results showed some species, particularly kahikatea (Dacrycarpus dacrydioides), the most abundant species in the bush, are being dispersed and establishing on properties predominantly within 250 m of the forest margin. These juveniles are not reaching maturity as most gardeners tend to remove all non-planted woody species. Qualitative interviews with 16 residents and a quantitative survey of the residents of 85 of the properties provided insights into the social context which these natural processes were operating. Using notions of place and performance I argue that gardens are continuously created and recreated by humans and non-humans. Residents attempt to create and maintain a garden that fulfils their individual and familial needs and desires (e.g., aesthetics, leisure and privacy), and public responsibilities such as ensuring they have a ‘neat’ and ‘tidy’ garden. This involves selecting plants for colour, shape and the care they require, and encouraging certain performances (e.g., flowering) while controlling other undesirable plants and performances (e.g. growth, spread and shading). While people make connections between native plants, belonging and identity; the ‘scientific’ demarcation between native and exotic species often becomes obscured as the garden is co-created by people and plants. Some plants become more significant than others but usually this is attributable to their performances rather than whether they are native or exotic. Residential gardens have the potential to play a major role in the conservation of species restricted to urban remnants. My research suggests that although the potential exists for woody species restricted to Riccarton Bush to naturally regenerate in nearby gardens, this will not happen without human intervention. Plants will need to be eco-sourced and propagated to avoid detrimental impacts on the genetic health of remnant populations, and then actively planted in gardens. The success of such planting initiatives will be increased by providing residents with information about the plants that are suitable for their performative needs and desires (e.g., the size, colour, and maintenance requirements of plants) and, most importantly, control over the location of plantings. In concluding, I argue that by adopting new concepts, theories and methodologies, the productivity, creativity and relevance of urban ecology can be significantly enhanced.

<p>In 1994 a new Forestry Act was accepted in Sweden. One of the aims of the law is to raise consideration forpreservation of biodiversity. Since the new law got accepted and some time has passed, there now lie someinterest in examining whether the law has been effective towards its purpose. Methods suitable for analysishave been examined during this study. The content of this pilot study is based around five parameters whichcan be used to validate the effects of the new law. The field study were executed in Orsa, Dalarna, Sweden ina managed forest where last clearcut was performed after 1994. The work consisted of measuring theparameters specified and comparing the results to reference data from before 1994. The parameters benefit tothe preservation of biodiversity is discussed in the report aswell as the differences between the Forestry Actfrom 1994 and the previous one. The parameters examined in this study were standing dead wood, treespecies, thick big trees, trees with cavities/cavernous trees and smaller areas saved for preservation. All ofthese plus a few other variables are being considered in the 30 § of the Forestry Act of 1994. The reportimplied that the variables had a positive effect on the preservation of biodiversity, and possible to beinvestigated within the restrictions of this study, seemed to have increased. Due to the size of the forest beingsmall and reference data for some parameters missing or covering larger areas, one must be careful wheninterpreting the results.In 1994 a new Forestry Act was accepted in Sweden. One of the aims of the law is to raise consideration forpreservation of biodiversity. Since the new law got accepted and some time has passed, there now lie someinterest in examining whether the law has been effective towards its purpose. Methods suitable for analysishave been examined during this study. The content of this pilot study is based around five parameters whichcan be used to validate the effects of the new law. The field study were executed in Orsa, Dalarna, Sweden ina managed forest where last clearcut was performed after 1994. The work consisted of measuring theparameters specified and comparing the results to reference data from before 1994. The parameters benefit tothe preservation of biodiversity is discussed in the report aswell as the differences between the Forestry Actfrom 1994 and the previous one. The parameters examined in this study were standing dead wood, treespecies, thick big trees, trees with cavities/cavernous trees and smaller areas saved for preservation. All ofthese plus a few other variables are being considered in the 30 § of the Forestry Act of 1994. The reportimplied that the variables had a positive effect on the preservation of biodiversity, and possible to beinvestigated within the restrictions of this study, seemed to have increased. Due to the size of the forest beingsmall and reference data for some parameters missing or covering larger areas, one must be careful wheninterpreting the results.</p>

The limited range of commercial timber species in Great Britain has led the forestry sector to consider wider planting of other species. This research addresses wood properties, particularly relevant to structural timber, of noble fir, Norway spruce, western red cedar and western hemlock in Great Britain. Sampling covered three regions to get a representative sample for the country. Bending stiffness, bending strength, density and twist distortion from drying were assessed. The results showed high yields of C16 for all these species, with Norway spruce and western hemlock performing comparatively well to typical British-grown Sitka spruce. Within this dataset, variation of mechanical properties within trees was more important than differences between species. Strength and stiffness increased with age, whereas density followed different trends in the inner and outerwood. The three properties were modelled based on ring number. The use of acoustic techniques to assess the mechanical properties of wood (in particular stiffness), was investigated in clears, sawn timber, logs and trees. The best results were found combining density with acoustic velocity in sawn timber. The use of acoustic techniques in standing trees was more reliable measuring distances of two or three metres, rather than the commonly used one metre; most likely due to a change in the wave propagation. Tree architecture was studied for timber production and quality. Noble fir described the highest merchantable taper profile. Branchiness varied importantly with height in the stem, and models were built for number, diameter and angle of branches. Western red cedar and western hemlock had fewer but thicker branches compared to noble fir and Norway spruce. Future work should produce grading machine settings and address the variation of timber quality and merchantability under different silvicultural regimes. This thesis concludes that the four species investigated can contribute to diversity the timber industry in Great Britain.

The analysis of the fertilization effects on wood productivity and tree-wood quality is important in forest plantations management.. The monitoring of these practices are generally defined by the continuous measurement of tree dimensions in permanent plots in periodic forest inventories. This methodology implies the availability of information restricted to a few years. On the other hand, the annual tree-ring analysis constitutes an efficient alternative methodology to the permanent plots uses. This study aimed to analyze the growth, wood density and nutritional concentration of 60 Pinus taeda trees treated with 6 different doses of composted pulp-mill sludge (CPMS): 0 , 20, 40, 80 and 100 t ha-1. Ten 17 year-old-trees for each treatment were selected, felled and wood cross sections (5 cm, thickness) were cut at the base, 1.30 m (DBH), 25, 50, 75 and 100% (6 cm, commercial trunk height). The annual tree-rings of the wood discs were delimitated and radial-longitudinally synchronized, and the tree stems reconstructed. Twin radial thin wood slices were cut transversely (DBH, trunk position), conditioned and analyzed by non-destructive techniques of X-ray densitometry and X-ray fluorescence (&mu;-XRF), to obtain the microdensity and wood nutrients profile. Width, density, biomass and nutrient concentration chronologies were analyzed by dendrochronological methods and correlated to seasonal variations of rainfall and temperature. Principal Component Analysis (PCA) was applied to explore the interaction of tree-ring variables, as well as analysis of variance (ANOVA) to verify the difference between treatments. The results analysis are presented in three chapters aiming to reach the main objective of this study. In Chapter I, the radial variation of the tree-ring microdensity and the integration of tree-ring density and width data in allometric equations were analyzed in order to improve the estimation of wood biomass production. Also, the response of the Pinus taeda trees to the CPMS treatments was dated. In Chapter II the response of the stem P. taeda trees development to the CPMS doses was analyzed. Increments of up to 24, 37 and 127% in the stem diameter, height and volume, respectively were observed. It is also proposed a management guide based on the simulation of P. taeda wood production under 84 t ha-1 CPMS for 21-year rotation and thinning at 7 and 13 years resulted in a wood productivity of 11.9 m3 ha-1 or 5.04 Mg ha-1 per year. In Chapter III the tree-ring nutrients concentration (phosphorus, sulfur, potassium, calcium, manganese and iron; P, S, K, Ca, Mn and Fe) were quantified. Ca and Mn decrease in the pith-bark direction; K and S decrease from the pith up to 8-9th annual tree-ring and, then, increase to the bark and Fe e P presented no distinguished radial trends. The results integration showed mainly correlations of P. taeda trees growth, wood density and nutrient concentration with local precipitation and significantly effects of CPMS soil fertilizer up to the 5th year after their application. This study provided an historical evaluation of growth, wood density and nutrient concentration of P. taeda trees. Evidencing the application of annual tree- rings in the monitoring of forest plantations under silvicultural treatments.<br>Na aplicação de fertilizantes em plantações é fundamental o entendimento e a avaliação do efeito na produtividade e qualidade da madeira das árvores das espécies florestais. Os processos de monitoramento destas práticas são, geralmente, definidos pela mensuração contínua das dimensões das árvores em parcelas permanentes em inventários florestais periódicos. No geral, esta metodologia de monitoramento implica na disponibilidade de informações restritas a poucos anos. Por outro lado, a análise dos anéis de crescimento anuais constitui-se em eficiente metodologia alternativa ao uso de parcelas permanentes. Neste contexto, o presente estudo visa analisar o crescimento, densidade e concentração de nutrientes dos anéis de crescimento anuais do lenho de 60 árvores de Pinus taeda de 17 anos de plantação experimental submetida a 6 tratamentos com resíduo celulósico compostado (CPMS), sendo: 0, 20, 40, 80 e 100 t ha-1. Foram selecionadas 10 árvores correspondentes a cada tratamento, cortados discos do lenho a 0, DAP, 25, 50, 75 e 100% da altura comercial do tronco (6 cm de diâmetro mínimo), delimitados e mensurados os anéis de crescimento na sua seção transversal e construído o crescimento radial-longitudinal do tronco das árvores. Amostras radiais gêmeas foram cortadas transversalmente do lenho dos disco do DAP do tronco, acondicionadas e analisadas por técnicas não destrutivas de densitometria de raios X e por fluorescência de raios X (&mu;-XRF), determinando-se a variação radial da microdensidade e dos nutrientes do lenho. As análises dendrocronológicas dos anéis de crescimento anuais propiciaram a construção das cronologias da largura, densidade, biomassa e concentração dos nutrientes, comparando-as com as variações sazonais de precipitação pluviométrica e de temperatura. Aplicou-se se a análise de componentes principais (PCA) para explorar a interação das variáveis dos anéis de crescimento, bem como a análise de variância (ANOVA) para verificar a diferença entre tratamentos. Os resultados das análises são apresentados em três capítulos atendendo ao objetivo do presente estudo. NoCapítulo I, analisou-se a variação radial da microdensidade dos anéis de crescimento, e a integração dos dados de densidade e largura dos anéis de crescimento em equacões alométricas para melhorar a estimativa da produção de biomassa de madeira. Ainda foi datada a resposta das árvores de Pinus taeda aos tratamentos com CPMS. No Capítulo II analisou-se o histórico da resposta do desenvolvimento do tronco das árvores de Pinus taeda às doses de CPMS, com incrementos de até 24, 37 e 127% no diâmetro, altura e volume do tronco, respectivamente. Propõe-se, ainda, a confecção de guia de manejo baseado na simulação da produção de madeira de P. taeda submetido a 84 t ha-1 CPMS para rotação de 21 anos e desbastes ao 7º e 13º ano resultando em produtividade de 11,9 m3 ha-1 ou 5,04 Mg ha-1 por ano. No capítulo III quantificou-se a concentração de nutrientes (fósforo, enxofre, potássio, cálcio, manganês e ferro; P, S, K, Ca, Mn e Fe) nos anéis de crescimento anuais das árvores. Observou-se que Ca e Mn diminuem na direção medula-casca; K e S diminuem da medula até o 8-9º anel, em seguida, aumentam na direção da casca, enquanto Fe e P não apresentaram tendências radiais. Os resultados integrados do histórico do crescimento, densidade da madeira e concentração de nutrientes no lenho das árvores de P. taeda mostraram que a variabilidade anual esta correlacionada, principalmente, com a precipitação local e com o efeito da aplicação de CPMS até cerca do 5º ano. O presente estudo propiciou a avaliação histórica do crescimento, densidade e concentração de nutrientes do lenho das árvores de Pinus taeda. Evidenciando a aplicação dos anéis de crescimento anuais no monitoramento de plantações florestais submetidas a tratamentos silviculturais.

Recycling felled urban trees that are hazardous or unhealthy is increasingly viewed as a viable practice to control disposal costs, promote environmental practices, and support local commerce. Wide spread waste wood utilization is encumbered by numerous presumptions about wood quantity, quality, accessibility, and presence of foreign objects; yet there is almost no scientific literature about these presumptions. Without this knowledge, informed decisions cannot be made about the viability of waste wood utilization. In this study, we assessed the quality and quantity of timber in street trees scheduled for routine removal by the District of Columbia (the District) using a modified timber grading protocol adapted from the United States Forest Service. We developed a second protocol to assess the feasibility of timber salvage by identifying physical barriers commonly encountered in urban areas (e.g., high volume traffic, utilities around the tree, and infrastructure). The randomized sampling scheme was stratified by land-use zones and focused on the six most abundant tree species: Acer platanoides, Acer rubrum, Acer saccharum, Quercus palustris, Quercus phellos, Quercus rubra. Our findings suggest the majority of condemned street trees are of too poor quality to contain timber (58% cull rate); however, trees that contain merchantable logs are likely to be easily removed. A notable discovery that could prove problematic for wood salvage was that the majority of trees (88%) contained superficial metal items embedded in the trunk surface. Furthermore, presence or absence of a merchantable-sized log (p=0.0445) depended on the tree's species, as did the average volume observed (p<0.0001). Additionally, land-use zones had an effect on the removal feasibility scores (p=0.0257) but had no effect on log presence or log volume. Throughout the District, we estimated that 36,500 board feet of merchantable logs are generated from routine removals of our top six species annually. These findings provide empirical data pertaining to urban timber salvage, which might aid decisions on the investment worthiness of utilizing urban street trees.<br>Master of Science

In this thesis, the application of NMR to the characterization and imaging of wood, and to wood in living trees, is investigated in two parts. The fIrst part characterises wood using advanced two dimensional (2-D) NMR measurements. The second part presents a novel portable magnet, purpose built for the imaging ofliving trees in-situ. The NMR relaxation parameters (T1 and T2) of the wood water components are established using standard one dimensional (I-D) procedures. Generally, three T2 components are found in wood with values of 10-100's ~s (small cell wall pores), 1-8 ms (larger cell wall pores) and lO's ms (lumen cavities). There are also three T1 components: a few ms (cell wall pores), lO's ms (latewood lumen) and -lOOms (earlywood lumen). Information on these components is furthered by application of the 2-D T1-T2 correlation experiment. T1-T2 spectra show that at T2 times of a few ms (cell wall pores), there are two components which have different T1 relaxation times: 12ms (peak C) and 85ms (peak B). Peak B is suggested to arise from exchange between peak C and lumen water. Another exchange peak (peak D) is identified at 0.05ms T2 and 58ms T1 (data from spruce at 45% MC). Peaks B and D are further investigated by 2-D T2-T2 correlation experiments, allowing fIrst estimates of the exchange times to be made. The time for exchange ofwaterl magnetisation between lumen and cell wall water was found to be 4.6ms and between smaller and larger cell wall pores to be 21ms.

This research examined Whole-Tree-Chip cleaning methods applicable to field operations in Pinus taeda L. (Loblolly pine) on the coastal plain of South Carolina. Objectives were: 1) to examine current and potential cleaning methods, and 2) develop and test two cleaning approaches suggested by past research. An open top chip van was modified to: a) determine the dispersion and composition of whole-tree-chip fractions by the installation of sampling buckets and floor pans and b) provide a platform for testing two cleaning systems. System one consisted of anti-clogging screens which pre-screened chips as they were discharged at the mill. It also allowed floor pans to sample the load for fines. System two utilized a radial blade blower which altered chip stream composition during loading by the Whole-Tree-Chipper. Eight trials were conducted over a six month period using a Morbark 22 chipper. Results indicated floor screens could have been more effectively positioned at the chip dump. As installed, and pin they successfully removed 1% of the load in fines chips. The best chip stream treatment involved double deflection: first from a vacuum assisted primary screen located in the van roof, and then from a passive screen located below and behind the first. This design reduced bark and fines by one-third.<br>Master of Science

Thesis (MSc)--Stellenbosch University, 2015.<br>ENGLISH ABSTRACT: This study aimed to classify wood from trees that were exposed to forest fires with regards to their end use. Exposure to high temperatures over time is known to degrade wood in various ways. This degradation could limit the end use by altering mechanical, chemical and physical properties, leading to difficulty in processing or failing to meet required specifications for various grades. In this study wood from Pinus radiata trees that were exposed to forest fires of different levels of heat intensity was analysed with regards to its anatomical and physical changes. Trees were visually classified into three classes of burn severity. Moisture content measurements were taken from 135 standing trees, divided among the three classes. 30 trees, 10 from each of the three classes, were sampled and used for CT analysis. Samples were taken to include growth from before and after the fire. Two samples were taken from each tree, one from the charred and one from the uncharred side. The CT data was analysed and used to measure properties like growth ring width, cell wall thickness, lumen diameter and cell wall density. The data was used to compare properties from the charred and uncharred sides within a given year, as well as compare properties between years. The study showed that there were significant differences in the MC between the burnt and unburnt sides of trees from classes 2 and 3. The difference between the MC measurements on the burnt sides of three classes differed significantly from each other. Lightness measurements were taken on samples from classes 2 and 3. These samples showed no significant difference between the burnt and unburnt sides for either of the two classes. The samples from the less exposed class were lighter, but not significantly so. The macroscopic wood density was determined using core samples. A decrease in wood density was observed with an increase in fire exposure. The mean densities for all three classes however still fulfilled the requirements for structural timber set by the SABS. Growth ring width, cell wall thickness and lumen diameter analysis gave varied results, with some cases showing a decline in properties while others were seemingly unaffected. For many of the outcomes of this study, results found by previous studies could not be reproduced.<br>AFRIKAANSE OPSOMMING: Hierdie studie het gepoog om bome wat aan plantasiebrande blootgestel is volgens hul eindgebruik te klassifiseer. Dit is bekend dat blootstelling aan hoë tempreature hout in vele maniere afbreuk. Hierdie afbreuking kan die eindgebruik van die hout beperk deur die meganiese, fisiese en chemiese eienskappe sodanig te verander dat dit kan lei tot probleme met verwerking of ongeskiktheid vir sterktegrade. In hierdie studie is Pinus radiata bome wat aan plantasiebrande van verskillende grade blootgestel is ondersoek in terme van hul fisiese en anatomiese veranderinge. Bome is visueel in drie klasse van verskillende brandskade gegroepeer. Voglesings is op 135 staande bome, verdeel tussen die drie klasse, geneem. Monsters is van 30 bome, 10 uit elke klas, geneem vir CT analiese. Monsters is so geneem dat dit groei van voor en na die brand ingesluit het. Daar is twee monsters van elke boom geneem, een van die gebrande en een van die ongebrande kant. Die CT data is geanalieseer en gebruik om eienskappe soos jaarringwydte, selwanddikte, lumendiameter en selwand digtheid te meet. Die data is gebruik om eienskappe tussen die gebrande en ongebrande kante, sowel as tussen jare te vergelyk. Die studie het gewys dat daar noemenswaardige verskille is tussen die voginhoud van die gebrande en ongebrande kante van bome uit klasse 2 en 3. Die voginhoud van die gebrande kante van al drie klasse verkil ook noemenswaardig van mekaar. Ligtheidmetings is gedoen op monsters van klasse 2 en 3. Die monsters het nie ‘n noemenswaardige verskil tussen die gebrande en ongebrande kante getoon nie. Alhoewel die klas 2 monsters ligter vertoon het as die klas 3 monsters, was die verskil nie betekenisvol nie. Houtdigtheid is bepaal deur fisiese metings op die monsters wat vir die CT skandering gebruik is te doen. ‘n Daling in digtheid met ‘n toename in blootstelling aan die brand het duidelik na vore gekom. Die digtheid is egter nog hoog genoeg om aan die vereistes vir strukturele hout te voldoen, soos die die SABS bepaal. Jaarringwydte, selwanddikte en lumen diameter het wisselende resultate opgelewer, met sommige gevalle wat ‘n afname in eienskappe wys en ander wat ooglopend onveranderd was. Vir vele van hierdie uitkoms kon die resultate van vorige studies nie bevestig word nie.

Commercial production of native tree and shrub species from seed can be unpredictable. Rosa corymbifera 'Laxa' is one such species of commercial importance as a rootstock, and is characteristic of the Rosaceae family. During the investigation, a standard commercial pretreatment was used to determine the unpredictable nature of this species with regard to germination. It was found that germination varied from as low as 2% in one year to a high of 63% in a subsequent year. The average germination was 26% over this period. This presents a very real dilemma to the grower with respect to meeting demand from highly unpredictable species. This dilemma is inherent in native tree production from seed. Germination became high and predictable with the addition of a compost maker, Garotta. During the same five year period the lowest germination achieved was 75% and the highest 99%. The average germination was 89%. Germination was vastly increased in percentage terms as well as becoming reliable from year to year. The benefits to the grower in using this technique are potentially great in terms of time and resources. Not only is this pretreatment highly predictable, it is safe and easy to apply, unlike alternatives such as the use of concentrated sulphuric acid to burn off the seed coat. During the pretreatment of Rosa corymbifera'Laxa' the influence of microorganisms was assessed. Microbes were found within the pretreatment and their presence was established as being required to overcome the dormancy of the seeds. Low microbial numbers and activity were found in the commercial pretreatment, resulting in low germination. High microbial numbers and activity were found in the Garotta pretreatment, resulting in high and predictable germination. Total absence of microbes was found to result in zero germination.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mathematics, 2017.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 233-244).<br>In this thesis, we study the mating of trees approach to Liouville quantum gravity decorated with SLE curves and its application to the scaling limit theory of decorated random planar maps. We focus on the less investigated regime where the SLE parameter K is larger than 8. We obtain three main results. First, we identify the covariance of the Brownian motion in the Mating of Trees Theorem for K > 8, answering a question of Duplantier-Miller-Sheffield. Second, we prove the joint convergence of bipolar oriented triangulations and their dual in the peanosphere topology, confirming a conjecture of Kenyon-Miller-Sheffield-Wilson. Third, we prove the joint convergence of the three trees and their dual in a uniformly sampled Schnyder wood in the peanosphere topology. The third result also yields a description of the continuum limit of a widely used planar embedding due to Schnyder. The scaling limits in the second and third results involve Peano curves coupled in the same imaginary geometry with different angles. In order to establish the scaling limits, we extend the mating of trees theory to multiple Peano curves in the same imaginary geometry.<br>by Xin Sun.<br>Ph. D.

Thesis (PhD(For))--Stellenbosch University, 2014.<br>ENGLISH ABSTRACT: Pinus patula is the most intensively planted conifer in the tropics and sub‐tropics. In South Africa Pinus patula plantations are the main saw‐log resource for structural lumber production. Improved intensive silvicultural practices and tree breeding have resulted in marked increases in the rate of growth. To reap the financial benefits of the faster growth, plantation managers are more and more inclined to reduce rotation ages, which inevitably results in the production of higher proportions of juvenile wood at final harvest, and lumber which often does not meet the minimum requirements for stiffness for structural lumber. Knowledge of the variation and the accurate prediction of the mechanical properties of the timber of standing trees can have various benefits for growers and processors of trees. It can be used for tree allocation to different processing facilities, for processing production planning, and to assist tree breeders to screen and select for superior breeding material. The objectives of this study were (1), to examine the within‐ and between‐tree variation in wood properties of young South African grown Pinus patula trees known to have important impacts on the suitability of sawn lumber for structural purposes and (2), to develop empirical prediction models for the flexural lumber properties from standing Pinus patula, based on variables that could be assessed non‐destructively from standing trees. Sample material was obtained from 170 trees (16‐20 years old) established in 17 compartments along the Mpumalanga escarpment of South Africa. A large number of variables which could be obtained non‐destructively from the trees while they were still standing, were measured. The trees were subsequently felled and two logs, 2.1 m in length, were extracted from each tree at two height positions. The 340 logs were processed into 1402 pieces of lumber for further measurements and destructive testing. Results showed that the mean modulus of elasticity measured on edge (MOEedge) was far below the limits set for structural grade softwood timber in South Africa. All the desirable properties for structural lumber improved with distance from the pith with the exception of the 5th percentile value for modulus of rupture (MOR), which was higher at the pith than for the boards processed adjacent to the pith. Boards processed from the lower part of the stem were superior in most of the important properties compared to those higher up in the stem. Separate multiple regression models for predicting the average dynamic MOE (MOEdyn) of individual boards, trees and compartments were developed. The models managed to explain 68%, 60% and 95% of the variation in MOEdyn respectively. The models developed for MOR explained 40% and 42% of variability at board and tree level respectively. At compartment level, 80% of the variation in the 5th percentile MOR value could be explained by the model. Sensitivity analyses showed that site index at base age of 10 years, acoustic time‐of‐flight, wood density and ring width were the most influential variables in the MOE models. The models indicated that tree slenderness during early growth seems to play a major role in determining the dynamic MOE and MOR of lumber. This is in agreement with Euler’s buckling theory and the bending stress theory. Microfibril angle (MFA) and density were measured on radial strips taken from a sub‐sample of trees with the Silviscan 3 technology. The mean microfibril angle per year ring in Pinus patula varied between 7o and 29o. In general MFA decreased with distance from the pith and height above ground level. A multiple regression model including microfibril angle, density and ring width explained 71% of the variation in the dynamic MOE of boards. Sensitivity analysis on the model showed that microfibril angle and density had roughly equal influences on predicting the MOEdyn of Pinus patula boards.<br>AFRIKAANSE OPSOMMING: Pinus patula is die mees aangeplante naaldhoutspesie in die tropiese en sub‐tropiese areas van die wêreld. Dit is die grootste bron van saagblokke vir die produksie van strukturele hout in SA. Intensiewe boskultuurpraktyke en boomteling het gelei tot ‘n merkbare verhoging in die groeitempo van die spesie. Plantasiebestuurders is gevolglik geneig om rotasie‐ouderdomme te verlaag, wat lei tot ‘n groter persentasie jeughout wat nie aan die minimum styfheidvereistes van strukturele hout voldoen nie. Kennis van die variasie en die akkurate voorspelling van die meganiese eienskappe van staande bome kan voordele inhou vir beide die verbouers en verwerkers van bome. Dit kan byvoorbeeld van hulp wees met die toewysing van bome aan verwerkingsfasiliteite, vir produksiebeplanning, en vir ondersteuning met die keuse van teelmateriaal vir boomtelers. Die doelwitte van hierdie studie was (1), om die binne– en tussenboomvariasie in die houteienskappe, wat ‘n bepalende invloed het op die geskiktheid van jong Suid Afrikaanse Pinus patula bome vir strukturele hout produksie, te ondersoek en (2), om empiriese modelle vir die voorspelling van die buigeienskappe van planke te ontwikkel, gebaseer op veranderlikes wat niedestruktief op staande Pinus patula bome ge‐evalueer is. Monsters vir die studie is verkry vanaf 170 bome (16‐20 jaar oud), geplant in 17 vakke op die Mpumalanga platorand van Suid Afrika. ‘n Groot aantal veranderlikes is nie‐destruktief gemeet op die staande bome waarna die bome gevel is en twee saagblokke, 2.1m in lengte, is op twee hoogte posisies uit elke boom verwyder. Die 340 blokke is verwerk tot 1402 planke vir verdere metings en destruktiewe toetse. Resultate het getoon dat die gemiddelde modulus van elastisiteit gemeet op die dwarskant (MOEedge) aansienlik laer was as wat vereis word vir strukturelegraad hout in Suid Afrika. Al die gewenste eienskappe het toegeneem met afstand vanaf die murg behalwe die 5de persentiel breekmodulus (MOR), wat hoër was vir murgplanke as vir aangrensende planke. Planke afkomstig van die laer dele van die stam het oor die algemeen beter eienskappe gehad as planke afkomstig van die hoër dele. Veelvuldige regressiemodelle kon 68%, 60% en 95% van die variasie in die gemiddelde dinamiese MOE (MOEdyn) op die vlak van onderskeidelik individuele planke, bome en vakke verklaar. Die modelle vir MOR kon 40% en 42% van die variasie op onderskeidelik plank‐ en boomvlak verklaar. Die model vir 5de persentiel MOR van vakke kon 80% van die variasie verklaar. ‘n Sensitiwiteitsanalise het aangetoon dat groeiplekindeks op ouderdom 10, akoestiese vlugtyd, digtheid en jaarringwydte die belangrikste veranderlikes was wat MOEdyn beïnvloed het. Die modelle het aangetoon dat die slankheid van bome tydens vroeë groei vermoedelik ‘n belangrike invloed op die MOEdyn en MOR van planke het. Dit is in ooreenstemming met Euler se knikteorie en die buigsterkteteorie. Die mikrofibrilhoek en digtheid van ‘n steekproef van die bome is gemeet met die Silviscan 3 apparaat. Die gemiddelde mikrofibrilhoek per jaarring het tussen 7 o en 29o varieer. Hierdie variasie was hoofsaaklik afhanklik van boomhoogte en aantal jaarringe vanaf die murg. ‘n Veelvuldige regressiemodel wat mikrofibrilhoek, digtheid en jaarringwydte insluit, kon 71% van die variasie in MOEdyn verklaar. ‘n Sensitiwiteitsanalise op die model het aangetoon dat mikrofibrilhoek en digtheid ongeveer ewe belangrik was wat betref hulle invloed op die voorspelde MOEdyn van Pinus patula planke.

The tropics are a key part of the global biosphere. Specifically, the woodland environments not only moderate large scale climate dynamics, but are also crucial in the global carbon cycle. Despite this, tropical dendrochronological studies are rare due to the uncertainty in annual dating from the minimal seasonality in most tropic environments. Without distinct annual tree rings, dendrochronological dating methods do not work, therefore other dating methods are required before long term forest growth analyses can be made. Alternatives such as radiocarbon and stable isotope measurements can be expensive and require high resolution measurement in order to identify seasonality. This thesis introduces a novel dating method for tropical trees using calcium as a tracer of annual wood formation. Laser Ablation-ICP-MS provides a fast, high resolution method for measuring mineral elements which could potentially provide a solution to the dating of tropical trees. Initially, Scots pine provided an excellent testing species for the development of both the methodological and analytical dating methods proposed through this thesis. It's well defined, annually dated ring structure formed the basis of seasonal signal detection and the development of an objective analysis for dating. This was achieved by the continuous measurement of calcium, and utilising a threshold detection approach to define annual growth cycles with respect to extreme peaks in the tracer data-series. The initial success of the calcium dating method using pine allowed for testing the technique on a tropical trees species from Cameroon which lacks distinct rings. Along with radiocarbon dating, the robustness of the calcium dating method for this tropical species was assessed. Promising results were initially found however, these could not be replicated and validation of this method proved problematic. Finally, radiocarbon dates were used to assess the nature of the oxygen and carbon stable isotopic series from the single tree of the same species from the tropical calcium tests. Results showed that despite the clear cyclic signal present in the oxygen isotope record, this did not represent an annual signal. These results reinforce the problems associated with tropical dendro analysis.

Metabolomics is an emerging field in functional plant biology that attempts to relate patterns in the molecular intermediates and products of metabolic pathways with genetic, gene expression, environmental and phenotypic traits - at the whole-tissue and/or whole-organism level. There is enormous potential for metabolomics tools to be applied in the study of tree species, and the demand for widespread application is promoting an ongoing evolution and refinement of newly-developed techniques. This body of research addresses the application of broad-scale, non-targeted metabolomics to questions of wood formation and quality in tree systems. Overall, it was shown that variation in metabolite profiles from developing xylem tissue was indeed correlated with the strength of specific phenotypic traits. Frequently, the strength of these relationships was such that phenotypic severity could be predicted accurately on the basis of metabolite profile data alone. The specific correlative patterns and metabolite/trait pairings observed in each study provided insight into the biological mechanisms by which these traits arise. Studies of secondary xylem development were conducted on breeding populations of Douglas-fir and radiata pine, as well as genetically modified hybrid poplar. In the Douglas-fir families studied, environment-induced variation in growth rate, fibre morphology and wood chemistry were correlated with metabolite profiles from developing xylem; metabolites involved in carbohydrate and lignin biosynthesis were primarily implicated in these relationships. Similarly, in juvenile trees from a series of radiata pine families, correlations were observed between metabolite profiles of developing xylem and the internal checking wood defect, a known heritable trait. In a different approach, two poplar hybrids, each modified separately with two exogenous gene constructs related to lignin biosynthesis, provided controlled model systems in which to investigate the interaction between genotype, metabolite profiles of developing xylem, and physico-chemical wood traits. Wood traits and metabolite profiles alike were altered by the genetic modifications, and it was found that the metabolic impact of the transgenes was not confined to pathways that were directly coupled to lignin biosynthesis. In fact, the scarcity of lignin-related metabolites in profiles from either the wild-type or modified genotypes suggested that metabolite channelling phenomena operate in the lignin biosynthetic pathway. Moreover, the analyses demonstrated that transgene-induced gradients in phenotypic traits could be associated with similar gradients within broad-scale metabolite profiles, and also that the wood-forming metabolisms of different poplar hybrids can respond similarly to the influences of genetic manipulation, at a global level. To conclude, the demonstrated associations between genotype, the metabolism of wood formation, and wood phenotype, as revealed by metabolite profiles, confirm the value of non-targeted metabolomics as a systems biology approach to understanding and modeling growth and secondary cell wall biosynthesis in trees.

Wood disks in various states of decay can be inexpensively preserved and prepared for accurate crossdating and precise tree-ring measurement by impregnation with commercial wood glue. The technique does not affect the dimensions or physiological features of samples preserved in this manner. Dead red spruce trees on Mt. Washington, New Hampshire, remain available for dendrochronological examination as long as 29 years after their last year of stem growth.

Trees exhibit many unique aspects of plant biology, one of which is the formation of wood. Wood is one of the most important natural products with a multitude of applications. The formation of wood (xylogenesis) is a highly ordered developmental process involving the patterned division and differentiation of the vascular cambium into secondary xylem and phloem tissue types. The progression of xylogenesis developmental process requires differential gene expression across the different tissue types. The tight regulation of wood formation is mediated by genes that regulate cambial meristem differentiation and xylem cell fate. MicroRNAs (miRNAs) are a group of endogenous ~ 20 to 24 nt RNA molecules that down regulate gene expression at the post-transcriptional level. MicroRNAs have validated roles in developmental processes through the regulation of meristem cell differentiation and developmental patterning in plants. They have been shown to spatially regulate differential gene expression patterns at different developmental stages. Thus, the vascular cambium and its derivatives are excellent candidate tissues for miRNA discovery. The aim of this M.Sc. study was to isolate microRNAs from actively differentiating tissues of two tree species in order to determine possible gene regulatory networks involved in early meristem differentiation, tissue patterning and secondary vascular development. A small RNA library from two-month old in vitro Populus trichocarpa plantlets was constructed to identify putative miRNAs contributing to the early postembryonic development of trees. This library, in conjunction with computational prediction of poplar miRNA homologues and precursor secondary structures, was used to identify a total of 72 poplar miRNAs. Sixteen of these were putative novel miRNAs, belonging to nine new miRNA families. A genome-wide search identified 55 putative target genes for the newly identified miRNAs. The target genes had diverse biological roles in developmental events and maintenance of cellular homeostasis. A number of the predicted targets were involved in plant organ development such as leaf cell fate, floral organ development and meristem differentiation. Other targets were involved in response to hormones, such as growth regulating factors and signaling proteins. Additionally, several targets were related to cellular metabolic processes, such as protein modification and ubiquitination. By isolating miRNAs from developing poplar plantlets, we were able to suggest possible developmental programmes under the control of these molecules, possibly affecting early seedling development and growth. A similar approach was used to identify miRNAs from three differentiating vascular tissues of Eucalyptus grandis. Isolated small RNA sequences were used in a search against all available bacterial artificial chromosome (BAC) shotgun genomic sequences from an ongoing Eucalyptus camaldulensis genome sequencing initiative at the Kazusa DNA Research Institute in Japan. We were able to characterize the first Eucalyptus miRNAs, and identified 48 putative miRNAs grouping into thirteen gene families. Twenty of the miRNAs belong to five families previously identified in other plant species, whereas the remaining 28 miRNAs grouped into eight putative novel miRNA families. Searches of the Populus and Arabidopsis annotated genomes revealed 45 putative target genes for the new families. Targets of particular interest included transcription factors involved in cell fate determination, including a MADS-box transcription factor involved in xylem formation. Further targets included auxin signaling proteins and auxin response factors, which could play a significant role during auxin regulation of vascular development. Expression profiling of the putative miRNAs using quantitative RT-PCR revealed that a number of the miRNAs exhibited differential expression patterns across xylogenic and non-xylogenic tissues. One miRNA showed expression in a single vascular tissue, whereas others were expressed at varying levels across the vascular tissues. This observation indicates a possible role for these putative miRNAs during vascular development and differentiation in eucalypt trees. In this study we used a combination of small RNA library construction and computational prediction to identify microRNAs from two tree species. We identified a total of 120 putative miRNAs grouping into 31 families. Of these, 44 group into 17 putative novel tree-specific miRNAs. This study has allowed the identification of novel miRNAs from a unique set of tissues, and has contributed to the ever-growing number of plant-specific miRNAs. The results of this study further contribute to our expanding knowledge of the unique developmental process of vascular tissue differentiation of perennial woody plants such as Eucalyptus and Populus species.<br>Dissertation (MSc (Genetics))--University of Pretoria, 2006.<br>Genetics<br>unrestricted

Lignin is a biopolymer mainly formed from the trans-isomers of the three precursors: p-coumaryl alcohol, coniferyl alcohols, and sinapyl alcohol. Lignin components are analyzed by a twenty year old novel technique called GCXGC. Twenty-three lignin standards were injection into one-dimensional gas chromatography mass spectroscopy using 5 different column polarities. Dispersion Zone Density coefficient was developed to screen 40 predictive plots generated using two models derived from the retention indices. Ten predictive plots were chosen using the DZD coefficient which produced the best separation for the multifunctional lignin standards. The lignin standards were identified and characterize using the GCXGC. The quantitative analysis of the authentication of GCXGC analysis show better separation then the initial prediction for both models. CE-ESI-MS was the other method used for the analysis of lignin standards and Milled Wood Lignin.

A computer simulation process to generate trees and then convert them into wood products is described. This process was researched and developed to aid Foresters in predicting the outcomes from varying forest management strategies. A number of statistical prediction methods were analysed and tested. A nearest neighbour method of prediction was chosen to generate the parameters of virtual trees with biological variation taken into account. This prediction method was chosen mainly because of its local nature and nonparametric form. The virtual trees are cut into various sized logs and then sawn into boards using defined sawing patterns and stored as ranges in the Cartesian coordinate system. Storage of the virtual trees and boards uses minimal computer memory. Value attributes are added to the sawn boards and the recovered volumes and values are analysed. A Visual Basic 5. 0 package was developed and is used to simulate the generation and conversion process.