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1
Gholipour, Hassan Fereidouni. "DETERMINANTS OF FOREIGN INVESTMENTS IN RESIDENTIAL PROPERTIES: EVIDENCE FROM MALAYSIAN STATES." International Journal of Strategic Property Management 17, no. 3 (September 23, 2013): 317–22. http://dx.doi.org/10.3846/1648715x.2013.822436.
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The last decade has witnessed a strong growth in foreign investments in residential properties (FIRP) in Malaysia. However, FIRP is not equally distributed among Malaysian states. Hence, this warrants an investigation into why some states have larger FIRP than others. The purpose of this paper is to investigate the pattern and determinants of FIRP in Malaysian states. FIRP in Malaysia has been agglomerated in the major and industrialized states (such as Kuala Lumpur, Selangor, Pulau Pinang and Johor). Using a panel of 14 Malaysian states over a period of 7 years (2004–2010) and applying the system Generalized Method of Moments (GMM) approach, the statistical results show that tourism agglomeration (learning about the host location), well-being of the local people, foreign investments in other sectors, religious diversity and minimum property purchase price are important determinants of FIRP.
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Silva-Laya, Silvia Josefina, Simón Pérez-Martínez, and Javier Álvarez-Del-Castillo. "Evaluación de sostenibilidad agroecológica de dos experiencias de producción con énfasis en hortalizas, Venezuela." Revista Colombiana de Ciencias Hortícolas 12, no. 3 (September 1, 2018): 632–45. http://dx.doi.org/10.17584/rcch.2018v12i3.7881.
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Esta investigación tuvo como objetivo evaluar la sostenibilidad de dos sistemas de producción agroecológica de hortalizas y plantas medicinales, en una zona periurbana (NUDES-La Limonera) y agrícola (FIRP) de Venezuela. Se realizaron observaciones descriptivas durante once meses entre 2014-2015. Se aplicó un cuestionario sociodemográfico; y se cuantificaron dieciséis indicadores de sostenibilidad en las dimensiones ecológica (IE), económica (IK) y sociocultural (ISc) mediante metodologías publicadas anteriormente. Se encontró que El NUDES-La Limonera forma parte de un proyecto político del Ejecutivo Nacional y sus indicadores de sostenibilidad alcanzaron niveles menos favorables, especialmente algunos IE (conservación de la vida en el suelo y dependencia de insumos externos) y IK (autosuficiencia alimentaria, papel del trabajo familiar, riesgo económico y diversidad de productos para la venta). Los ISc muestran mayor fortaleza, particularmente en la densidad de relaciones con otros colectivos, sin embargo, la satisfacción de necesidades básicas como la vivienda no fue satisfactorio ya que la tierra no es propia (solo la guardia y custodia). La FIRP forma parte de una iniciativa de productores organizados para la diversificación agrícola de los Andes venezolanos. Presentó los valores más favorables a la sostenibilidad en las tres dimensiones. Vale destacar que IK, la productividad y rentabilidad resultaron óptimos en los tres últimos años analizados y en ISc, la tierra es propia. Los resultados permitieron entender la importancia de las sinergias que se generan con las interacciones en los sistemas productivos como estrategia de sostenibilidad.
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Freund, M. M., T. Hirao, T. Matsumoto, S. Sato, T. Watabe, G. K. Brubaker, L. Duband, et al. "A Far Infrared Photometer (FIRP) for the Infrared Telescope in Space (IRTS)." Advances in Space Research 13, no. 12 (December 1993): 505–8. http://dx.doi.org/10.1016/0273-1177(93)90158-8.
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Hanberry, Brice B., Donald C. Justice, and David C. Powell. "Discovering Douglas-Fir Woodlands in the Historical Forests of Umatilla National Forest, Eastern Oregon and Washington." Forests 11, no. 10 (October 21, 2020): 1122. http://dx.doi.org/10.3390/f11101122.
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We discovered unique Douglas-fir open woodlands in the Umatilla National Forest using historical surveys. Historical ponderosa pine forests of the western United States are transitioning to denser forests comprised of a greater proportion of fire-sensitive species, including true firs. We used historical (1879 to 1887) surveys to quantify the composition and structure of the Umatilla National Forest in eastern Oregon and Washington and provided contemporary forest information for comparison. We also modeled fir and pine distributions using environmental predictors and the random forests and extreme gradient boosting classifiers. Historically, ponderosa pine and Douglas-fir comprised about 80% of all trees, with western larch relatively abundant at 10% of all trees. Currently, ponderosa pine and Douglas-fir are about 40% of all trees, while grand fir and lodgepole pine increased from rare species to about 40% of all trees. Historical density was about 165 trees/ha (trees > 12.7 cm in diameter). The wetter north unit of steep slopes and predominantly Douglas-fir was about 120 trees/ha, or open woodlands, whereas the drier, flatter south units of predominantly ponderosa pine were about 210 trees/ha, and densities of 160 and 190 trees/ha occurred on flat and gentle slopes, respectively, with predominantly ponderosa pine. Currently, Umatilla National Forest averages about 390 trees/ha; the north unit of grand fir and Douglas-fir tripled in density to 365 trees/ha, whereas the south units of ponderosa and lodgepole pines doubled in density to 410 trees/ha. Douglas-fir woodlands are an unusual combination of a relatively fire-sensitive tree species with an open structure, which may result from surface fires that remove tree regeneration, resulting in one layer of trees over an understory of herbaceous and shrubby vegetation. We interpreted that a spatially and temporally variable fire return interval favored Douglas-fir, but fires were frequent enough to allow herbaceous vegetation and shrubs to out-compete trees, maintaining the balance between trees and other vegetation in woodlands. Fire exclusion has resulted in forest-type transition and also an information deficit about circumstances under which relatively fire-sensitive Douglas-fir instead of fire-tolerant ponderosa pine would establish at low densities over large extents.
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Filip, Gregory M., Helen Maffei, and Kristen L. Chadwick. "Forest Health Decline in a Central Oregon Mixed-Conifer Forest Revisited After Wildfire: A 25-Year Case Study." Western Journal of Applied Forestry 22, no. 4 (October 1, 2007): 278–84. http://dx.doi.org/10.1093/wjaf/22.4.278.
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Abstract A 500-ac mixed-conifer forest near Cache Mountain in central Oregon was examined in 1979, 1992, 2002, 2004, and 2005 to document causes of forest health decline and subsequent wildfire damage. The site is dominated by grand fir (Abies grandis) and ponderosa pine (Pinus ponderosa), with some lodgepole pine (Pinus contorta) and subalpine fir (Abies lasiocarpa). Part of the area was clearcut or shelterwood harvested from 1983 to 1985. Between 1979 and 1992, grand fir increased substantially, whereas ponderosa pine decreased in stems and basal area/ac in the unharvested areas. From 1979 to 2002, grand fir experienced severe mortality that was caused primarily by the root pathogen, Armillaria ostoyae, and the fir engraver (Scolytus ventralis). In 2003, a wildfire burned all of the study area, and by 2004, most of the grand fir, subalpine fir, and lodgepole pine was killed. The least amount of mortality from fire occurred in the larger-diameter ponderosa pine. Two years after the 2003 fire, some of the grand firs with bole or crown scorch that were alive in 2004 were killed by fir engravers by 2005. For ponderosa pines, only a few trees with bole or crown scorch that were alive in 2004 were killed by bark beetles, mostly mountain pine beetle (Dendroctonus ponderosae) and red turpentine beetle (Dendroctonus valens), by 2005. This case study has relevance to current interpretations of forest health in similar mixed-conifer forests, the major causes of forest health decline, and the role of fire in forest health.
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Lowell, Eini C., and James M. Cahill. "Deterioration of Fire-Killed Timber in Southern Oregon and Northern California." Western Journal of Applied Forestry 11, no. 4 (October 1, 1996): 125–31. http://dx.doi.org/10.1093/wjaf/11.4.125.
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Abstract Deterioration of fire-killed timber in the coastal mountains of southern Oregon and northern California was monitored over a 3 yr period (1988-1990). Defect was identified and measured on felled and bucked sample trees by using Scribner and cubic scaling rules. Douglas-fir (Pseudotsuga menziesii), grand fir (Abies grandis), white fir (A. concolor),ponderosa pine (Pinus ponderosa), and sugar pine (Pinus lambertiana), covering a wide range of geographic areas, site conditions, and tree size and age, were studied. One year after death, Douglas-fir, sugar pine, and ponderosa pine had lost about 1% and the true firs 5% of their cubic volume. The sapwood of the pines was heavily stained. The occurrence of sap rot and weather checks increased the second year. Percent loss in all species was correlated with small-end scaling diameter. A logistic regression model predicting the incidence of cull was developed for use on logs that have been dead for 3 yr. West. J. Appl. For. 11(4):125-131.
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Poage, Nathan J., Peter J. Weisberg, Peter C. Impara, John C. Tappeiner, and Thomas S. Sensenig. "Influences of climate, fire, and topography on contemporary age structure patterns of Douglas-fir at 205 old forest sites in western Oregon." Canadian Journal of Forest Research 39, no. 8 (August 2009): 1518–30. http://dx.doi.org/10.1139/x09-071.
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Knowledge of forest development is basic to understanding the ecology, dynamics, and management of forest ecosystems. We hypothesized that the age structure patterns of Douglas-fir at 205 old forest sites in western Oregon are extremely variable with long and (or) multiple establishment periods common, and that these patterns reflect variation in regional-scale climate, landscape-scale topography, and landscape-scale fire history. We used establishment dates for 5892 individual Douglas-firs from these sites to test these hypotheses. We identified four groups of old forest sites with fundamentally different Douglas-fir age structure patterns. Long and (or) multiple establishment periods were common to all groups. One group described old forests characterized by substantial establishment from the early 1500s to the mid-1600s, with decreasing establishment thereafter. Another group was characterized by peaks of establishment in the middle to late 1600s and in the late 1800s and early 1900s. A third group was characterized by a small peak of establishment in the mid-1500s and a larger peak in the middle to late 1800s. Characteristic of the fourth group was the extended period of Douglas-fir establishment from the late 1600s to the late 1800s. Group membership was explained moderately well by contemporary, regional climatic variables and landscape-scale fire history, but only weakly by landscape-scale topography.
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Cimaglia, Riccardo. "Relative indirette libere e causali indirette libere nella narrativa italiana ottocentesca." Revue Romane / Langue et littérature. International Journal of Romance Languages and Literatures 48, no. 2 (December 5, 2013): 221–53. http://dx.doi.org/10.1075/rro.48.2.02cim.
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In this paper I will analyze two subordinate clauses which can be frequently found within free indirect reported speech (FIRS, in the paper DIL): relative and causal clauses. After a short illustration of FIRS I will examine the two clauses with an analysis of the passages in FIRS from Italian narrative literature of the XIX century (especially Manzoni and Verga). A relative or a causal clause can recur within a FIRS passage, can open it or can constitute on its own a FIRS passage becoming, respectively, free indirect relative clause (FIRC, in the paper RIL) and free indirect causal clause (FICC, in the paper CIL). FIRC and FICC share two peculiarities: a) They have a rhematic function; b) They are cases of “hypotactizated parataxis” (FIRC and FICC, as subordinate clauses, connect a FIRS passage to the diegesis without the break of the normal FIRS, paratactically juxtaposed to the narratum). For this last peculiarity FIRC and FICC represented two important stylistic means for the novelists of the Realism to attain the impersonality of the author in the novel through a close fusion between the voice of the author and the voice of the characters.
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Bélanger, Louis, Daniel Allard, and Philippe Meek. "Dynamique d'établissement d'un peuplement bi-étagé de bouleau blanc et de sapin baumier en zone boréale." Forestry Chronicle 69, no. 2 (April 1, 1993): 173–77. http://dx.doi.org/10.5558/tfc69173-2.
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The age structure of a boreal two-storied stand formed by an upperstory of white birch (Betula papyrifera Marsh.) with an understory of balsam fir (Abies balsamea (L.) Mill.) was analysed. The establishment of this 50-year stand followed a burn that ran through a cut-over area. The objective was to verify if the establishment of the fir understory followed the traditional succession model or the initial floristic composition model. The age structure analysis indicated an immediate and rapid establishment of white birch during a period of 6 years after the fire. Establishment of fir, however, was initiated only 16 years after the fire. Peak establishment was 33 years after the fire. Fir regeneration followed a cycle. The regeneration pattern was characterized by the absence of fir establishment the first 16 years after the fire, followed by sporadic fir regeneration the next 12 years, then by a 13-year period of abundant regeneration after which there was a complete halt to fir regeneration. So, in this case, the successional model was more fit to describe the dynamics of balsam fir. The absence of fir regeneration during the initial period after the fire could be explained by the absence of the nearby fir seed sources due to harvesting. However, the total absence of fir establishment during the last period is more difficult to explain. Seedbed evolution since the fire could possibly be in cause. This and other studies indicate that in the boreal balsam fir-white birch ecoclimatic domain vegetation dynamic after fire does not limit itself to one pathway. Stand regeneration after fire is significantly affected by local conditions.
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Shimajiri, Yoshito, S. Takahashi, S. Takakuwa, M. Saito, and R. Kawabe. "Interaction between molecular outflows and dense gas in the cluster-forming region OMC-2/FIR4." Proceedings of the International Astronomical Union 2, S237 (August 2006): 475. http://dx.doi.org/10.1017/s1743921307002633.
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AbstractSince most stars are born as members of clusters (Lada & Lada 2003), it is important to clarified the detailed mechanism of cluster formation for comprehensive understanding of star formation. However, our current understanding of cluster formation is limited due to the followings; (a)Cluster forming regions are located at the far distance.(b)There are complex mixtures of outflows and dense gas in cluster forming regions. So, we focused on the Orion Molecular Cloud 2 region (OMC-2), a famous cluster-forming region (Lada & Lada 2003) and the most nearest GMC. We observed the FIR 4 region with the Nobeyama Millimeter Array(NMA), Atacama Submillimeter Telescope Experiment (ASTE). In this region, there are 3 protostars (FIR3, FIR4, FIR5) which were identified as 1.3 mm dust continuum sources (Chini et al. 1997) and driving sources of mixed outflows, and FIR 4 is the most strongest source of 1.3 mm dust continuum in OMC-2. Molecular lines we adopted are a high density (105cm−3) gas tracer of H13CO+ (J=1-0), a molecular outflow tracer of 12CO(J=1-0) and 12CO(J=3-2), and SiO(J=2-1 v=0) as a tracer of shocks associated with an interaction between outflows and dense gas.From results of the 12CO(J=1-0) outflow, H13CO+ dense gas, and the SiO shock, the outflow from FIR 3 interacts with dense gas in the FIR 4 region. Moreover the Position-Velocity diagram along the major axis of the 12CO(J=3-2) outflow shows that the 12CO(J=1-0) and SiO emission exhibits a L shape (the line widths increase in the interacting region in morphology). This is an evidence of interaction between the outflows and dense gas (Takakuwa et al. 2003). From result of the 3 mm dust continuum, the interacted region by the molecular outflow of FIR 3 is an assemble of seven dense cores. The mass of each core is 0.1-0.8 M. This clumpy structure is evident only at FIR 4 in the entire OMC-2/3 region. There are possible that two cores are in the proto-stellar phase, because 3 mm dust continuum source correspond to NIR source or 3.6 cm f-f jet source. From these results, cores in the FIR 4 region may be potential source of the next-generation stars. In the other words, there is a possibility that the molecular outflow ejected from FIR 3 is triggering the cluster formation in the FIR 4 region.
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Hood, Sharon M., Charles W. McHugh, Kevin C. Ryan, Elizabeth Reinhardt, and Sheri L. Smith. "Evaluation of a post-fire tree mortality model for western USA conifers." International Journal of Wildland Fire 16, no. 6 (2007): 679. http://dx.doi.org/10.1071/wf06122.
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Accurately predicting fire-caused mortality is essential to developing prescribed fire burn plans and post-fire salvage marking guidelines. The mortality model included in the commonly used USA fire behaviour and effects models, the First Order Fire Effects Model (FOFEM), BehavePlus, and the Fire and Fuels Extension to the Forest Vegetation Simulator (FFE-FVS), has not been tested with independently collected post-fire tree mortality data. The model predicts mortality for a wide range of conifer species based on crown scorch and species-specific bark thickness. We evaluated the mortality model on 13 western USA conifers: subalpine fir, red fir, white fir, Douglas-fir, incense cedar, western larch, western hemlock, Engelmann spruce, whitebark pine, lodgepole pine, ponderosa pine, Jeffrey pine, and sugar pine. Predicted stand-level mortality was within ±20% of observed mortality for all species except incense cedar, western larch, red fir, and western hemlock. Individual tree mortality prediction was most accurate for subalpine fir, incense cedar, ponderosa pine, and Jeffrey pine. Evaluation of the model provides managers with an accuracy assessment for estimating the probability of mortality for the majority of western USA conifers when using the mortality model to make land management decisions.A
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Levine, Carrie R., Flora Krivak-Tetley, Natalie S. van Doorn, Jolie-Anne S. Ansley, and John J. Battles. "Long-term demographic trends in a fire-suppressed mixed-conifer forest." Canadian Journal of Forest Research 46, no. 5 (May 2016): 745–52. http://dx.doi.org/10.1139/cjfr-2015-0406.
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In the western United States, forests are experiencing novel environmental conditions related to a changing climate and a suppression of the historical fire regime. Mixed-conifer forests, considered resilient to disturbance due to their heterogeneity in structure and composition, appear to be shifting to a more homogeneous state, but the timescale of these shifts is not well understood. Our objective was to assess the effects of climate and fire suppression on stand dynamics and demographic rates of an old-growth mixed-conifer forest in the Sierra Nevada. We used a Bayesian hierarchical analysis to quantify species and community rates of recruitment, growth, and mortality. Despite a warming climate, we found that stand density, basal area, and carbon have increased over 56 years. Fir recruitment and growth significantly exceeded the community-level median rates, whereas pine recruitment and growth was significantly lower than the community-level median rates. Shifts in species composition from a well-mixed stand to a more dense fir-dominated stand appear to be driven by low growth and recruitment rates of pines relative to firs. In forests such as these with consistent and relatively low mortality rates, we recommend that restoration and management activities be focused on promoting pine recruitment and growth.
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Higgins, Anna M., Kristen M. Waring, and Andrea E. Thode. "The effects of burn entry and burn severity on ponderosa pine and mixed conifer forests in Grand Canyon National Park." International Journal of Wildland Fire 24, no. 4 (2015): 495. http://dx.doi.org/10.1071/wf13111.
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Over a century of fire exclusion in frequent-fire ponderosa pine and dry mixed conifer forests has resulted in increased tree densities, heavy surface fuel accumulations and an increase in late successional, fire-intolerant trees. Grand Canyon National Park uses prescribed fires and wildfires to reduce fire hazard and restore ecosystem processes. Research is needed to determine post-fire vegetation response thus enabling future forest succession predictions. Our study focussed on the effects of burn entry and burn severity on species composition and regeneration in two forest types: ponderosa pine with white fir encroachment and dry mixed conifer. We found no difference in tree composition and structure in a single, low-severity burn compared with unburned areas in the white fir encroachment forest type. We found no white fir seedlings or saplings in a second-entry, low-severity burn in the white fir encroachment forest type. Second-entry burns were effective in reducing white fir densities in the white fir encroachment forest type. There was significant aspen regeneration following high-severity fire in the dry mixed conifer forest type. This research suggests that repeated entries and an increase in burn severity may be necessary for prescribed fire or wildfire to be effective in meeting management objectives.
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Chastagner, Gary, L. Eric Hinesley, and Jeff Owen. "Effect of Two Fire Retardants on Postharvest Drying and Flammability of Douglas Fir and Fraser Fir Christmas Trees." HortScience 43, no. 1 (February 2008): 203–5. http://dx.doi.org/10.21273/hortsci.43.1.203.
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SafeTree Christmas Tree Fire Retardant was applied to freshly harvested Douglas fir [Pseudotsuga menziesii (Mirb.) Franco] boughs, and RapidCool FRX Christmas Tree Retardant was applied to freshly cut Fraser fir [Abies fraseri (Pursh) Poir.] boughs. The flame retardants were sprayed onto the foliage. Fire retardant accelerated the drying rate of Douglas fir boughs, which increased flammability. RapidCool fire retardant did not slow the drying rate of Fraser fir boughs, and had no effect on moisture content (MC) at ignition, flame time, total burn time, or total foliage consumed. For both species, initial ignition and spread of flame occurred at 60% to 70% MC. Fresh boughs did not ignite in burn tests and were not a fire hazard. Twig MC of nontreated Fraser fir increased 20% during display in water, further decreasing the possibility of ignition when exposed to a flame. Neither product was effective as a fire retardant on boughs of Christmas trees.
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Pitcher, Donald C. "Fire history and age structure in red fir forests of Sequoia National Park, California." Canadian Journal of Forest Research 17, no. 7 (July 1, 1987): 582–87. http://dx.doi.org/10.1139/x87-098.
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The relationship between historical fires and age structure was examined on three plots in red fir (Abiesmagnifica var. shastensis Lemm.) forests within Sequoia National Park, California, U.S.A. All trees greater than 0.1 m in height were mapped and aged. Fire history was determined from 16 fire-scar sections. Red fir trees are more shade tolerant, longer lived, larger, and slower growing than western white pine (Pinusmonticola Dougl.) on the plots. No fires have occurred since 1886, but prior to that time the average fire-free interval was 65 years. Most of the trees on two of the plots originated after fires, but on the third plot red fir regeneration was delayed for at least 60 years following the last fire. Structural differences between the plots were linked to variations in fire behavior. The decrease in fire frequencies in this century may have led to a decrease in red fir establishment. Excluding the most recent period, the forest age structure is in something of a steady state that approximates a negative exponential age-class distribution.
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Bouchard, Mathieu, David Pothier, and Sylvie Gauthier. "Fire return intervals and tree species succession in the North Shore region of eastern Quebec." Canadian Journal of Forest Research 38, no. 6 (June 2008): 1621–33. http://dx.doi.org/10.1139/x07-201.
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We evaluated geographic variations in mean fire return intervals and postfire forest succession within a 66 497 km2 land area located in the eastern Quebec boreal forest. Fire return intervals were calculated using a time since last fire map for 1800–2000, and forest dynamics were studied by superimposing 3204 forest inventory plots onto the fire map. Mean fire return interval proved significantly shorter in the western part of the study area, at 270 years, compared with the eastern part, where it was probably more than 500 years. The two main tree species in the study area were balsam fir ( Abies balsamea (L.) P. Mill.) and black spruce ( Picea mariana (Mill.) BSP). Balsam fir abundance increased progressively as a function of time since fire, whereas black spruce abundance increased during the first 90 years after fire and then declined. Balsam fir was significantly more abundant in the southeastern portion of the study area, which we attribute to the combined limitations imposed by temperature along the north–south axis and by fire along the east–west axis. Large forest patches (i.e., ≥200 km2) dominated by early successional tree species, within a matrix of irregular black spruce – balsam fir mixtures, are an important feature of preindustrial forest landscapes in this region.
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McRae, D. J. "Prescribed Burning for Stand Conversion in Budworm-killed Balsam Fir: An Ontario Case History." Forestry Chronicle 62, no. 2 (April 1, 1986): 96–100. http://dx.doi.org/10.5558/tfc62096-2.
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Recent spruce budworm (Choristoneura fumiferana [Clem.]) infestations have resulted in widespread areas of balsam fir (Abies balsamea [L.] Mill.) mortality in Ontario, and there is growing interest in reestablishing these areas quickly as productive forests. One technique being used is prescribed fire after a salvage and bulldozer tramping operation. A 445-ha prescribed burn was carried out under moderate fire danger conditions in northern Ontario. The site, which was covered by balsam fir fuel that had been killed by spruce budworm, was tramped to improve fire spread. Weather, fuel consumption, and fire effects are reported. The burn effectively reduced heavy surface fuel loadings and consequently planting on the site was easier. Key words: Prescribed burning, fire, spruce budworm. Choristoneura fumiferana, balsam fir, Abies balsamea, fuel consumption, site preparation, tramping, stand conversion.
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Barrett, Stephen, and Stephen Arno. "Fire History of the Lamar River Drainage Yellowstone National Park." UW National Parks Service Research Station Annual Reports 14 (January 1, 1990): 131–33. http://dx.doi.org/10.13001/uwnpsrc.1990.2911.
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In this paper we discuss the first phase of a 3-year effort to document the fire history of Yellowstone National Park's (YNP) Lamar River drainage southeast of Soda Butte Creek. The overall goal of the study was to provide managers with a more complete understanding of YNP natural fire regimes. Specific objectives were: 1. Determine natural (pre-1900) fire periodicities, severities, burning patterns, and post-fire succession within the study area's major forest types (Douglas fir/ grassland, lodgepole pine/subalpine fir/ spruce, whitebark pine/lodgepole pine/ subalpine fir, and whitebark pine/subalpine fir timberline habitats); 2. document and map the pre-1988 forest age-class mosaic; and 3. digitize the age-class mosaic map for the YNP's GIS data base. This study is considered especially timely because the 1988 fires destroyed much evidence of area fire history. Our sampling in 1989 focused on a 24,000 ha area encompassing the Cache Creek drainage, which was severely burned in 1988. The forest age-class mosaic was sampled by increment boring and sawing fire scar samples from old trees (Arno and Sneck 1977, Barrett and Arno 1988). Aerial photographs were used to map the pre-1988 forest age-class mosaic; Data was digitized for the park's GIS data base. Information from the YNP fire atlas also was useful in interpreting fire patterns during the post-1900 period.
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Couillard, Pierre-Luc, Serge Payette, and Pierre Grondin. "Long-term impact of fire on high-altitude balsam fir (Abies balsamea) forests in south-central Quebec deduced from soil charcoal." Canadian Journal of Forest Research 43, no. 2 (February 2013): 188–99. http://dx.doi.org/10.1139/cjfr-2012-0414.
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Extensive balsam fir (Abies balsamea (L.) Mill.) stands across the southern boreal forest are ecosystems likely more influenced by insect outbreaks and windthrows than by fire. To what degree the dominance of balsam fir stands reflects past and present disturbance dynamics associated with fire is not well documented. To answer this question, we focused on the reconstruction of the long-term fire history of high-altitude balsam fir forests of southern Quebec. The reconstruction was based on botanically identified and radiocarbon-dated soil charcoal particles in 19 sites covering successional stages from white birch (Betula payrifera Marsh.) to mixed white birch – balsam fir stands. Fire activity commenced early after deglaciation, about 9600 calibrated years before present when the first boreal tree species were established. Fire occurred recurrently during the following 5000 years with a forest landscape composed of the principal tree species common to the boreal forest, including jack pine (Pinus banksiana Lamb.). Fire activity ceased more or less abruptly about 4500 years ago due to less fire-conducive, more humid conditions. Then, the forest landscape progressively changed towards a larger representation of white birch – balsam fir forests and the disappearance of jack pine. Whereas several balsam fir stands have not burned over the last 4500 years, scattered fires occurred in particular over the last 250 years when 1815 and 1878 fires, probably man-made, burned 50% of the forest, thus causing a major change in the composition of the forest landscape. It is concluded that the high-altitude forest landscape of southern Quebec changed profoundly over the Holocene in close association with a time-transgressive dry-to-wet climatic gradient.
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Allini, Alessandra, Luca Ferri, Marco Maffei, and Annamaria Zampella. "Determinants of financial instruments risk disclosure: An empirical analysis in the banking sector." Corporate Ownership and Control 17, no. 2 (2020): 20–31. http://dx.doi.org/10.22495/cocv17i2art2.
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This study investigates the effects of firm and country factors, considered as determinants of the financial instruments risk disclosure (FIRD) proxied by IFRS 7 in the European banking system. We select 582 banks-year observations based on the largest five European economies (France, Germany, Italy, Spain and the UK) as provided by the International Monetary Fund (IMF). Our analysis covers a period of 8 years (2007-2014) and adopts an OLS model. Results show that both firm (the type of auditor, board size and profitability) and country factors (financing environment, regulatory environment, and organizational status) affect FIRD. Limitations for this paper could relate to country selection, as well as on the breadth of the sample. Nevertheless, these aspects could unveil possible areas of future inquiry. The contribution of the study is twofold. It enriches the literature about firm and country determinants on financial instruments risk disclosure, as combined rather than single-standing variables. Yet, it draws the attention of banks’ management and investors on what the crucial factors to reach an optimal level of FIRD are and gain the confidence of capital markets, reducing information asymmetries. This is the first empirical investigation on the determinants of FIRD, using IFRS 7, in the European banking sector that adopts firm and country factors in a combined effort.
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Meyer, Marc D., Becky L. Estes, Amarina Wuenschel, Beverly Bulaon, Alexandra Stucy, Douglas F. Smith, and Anthony C. Caprio. "Structure, diversity and health of Sierra Nevada red fir forests with reestablished fire regimes." International Journal of Wildland Fire 28, no. 5 (2019): 386. http://dx.doi.org/10.1071/wf18114.
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The reestablishment of natural fire regimes may benefit forest ecosystems by restoring their fundamental structural, compositional or functional attributes. We examined the influence of fire on the structure, understorey diversity and health of red fir (Abies magnifica) forests by comparing burned and unburned stands in 22 separate, paired fires of Yosemite, Sequoia and Kings Canyon National Parks and the Giant Sequoia National Monument. Burned red fir plots were characterised by lower tree densities and canopy cover, restored spatial heterogeneity and higher understorey species richness than unburned plots. Densities of large trees and large snags and red fir regeneration were similar between burned and unburned sites. Forest health indicators were similar between burned and unburned sites, and red fir crown loss ratings were primarily associated with topographic variables indicative of increased moisture stress or reduced soil moisture availability (i.e. lower elevations, south-facing slopes). Our results suggest that fire does not improve the health of red fir trees especially in areas of greater moisture stress, but it can restore red fir forest structure, increase understorey diversity and enhance adaptive capacity in landscapes with reestablished fire regimes.
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Zhang, Jian, Shao Fei Yuan, Kui Hong Wang, and Qin Li. "Study on the Effects of Microwave Pretreatment on the Fire Retardant Permeability of Fast-Growing Wood." Applied Mechanics and Materials 423-426 (September 2013): 1334–38. http://dx.doi.org/10.4028/www.scientific.net/amm.423-426.1334.
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The paper preheated poplar and Chinese fir with microwave before dipping into fire retardant solution with the purpose of improving their permeability. The test results showed that microwave increased the routs for liquid which proved to be a feasible way to facilitate fire retardant solution to enter into wood. Fire retardant loading dosage (FRLD) and implantation depth (ID) increased for both poplar and Chinese fir. Fire retardant properties such as oxygen index (OI), mass loss rate (MLR) and flame combustion time (FCT) increased and can meet the fire retardant wood requirements defined by standard of GA/T 42.1-92.
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Couillard, Pierre-Luc, Serge Payette, and Pierre Grondin. "Recent impact of fire on high-altitude balsam fir forests in south-central Quebec1This article is one of a selection of papers from the 7th International Conference on Disturbance Dynamics in Boreal Forests." Canadian Journal of Forest Research 42, no. 7 (July 2012): 1289–305. http://dx.doi.org/10.1139/x2012-081.
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The dynamics of high-altitude balsam fir ( Abies balsamea (L.) Mill.) forests is mainly driven by insect outbreaks and windthrows. However, very little work has been done on the role of fire on the development and maintenance of this ecosystem. In this study, we document the role of fire in the high-altitude balsam fir forests of the Réserve Faunique des Laurentides (RFL), southern Quebec. Sixteen sites were sampled among six different forest types described according to plant composition and fire evidence. At each site, the diameter structure was recorded and stand age was calculated based on tree-ring dating of individual trees and radiocarbon-dated surficial charcoal samples. Fire played a major role in the recent dynamics of high-altitude fir forests in the RFL. Over the last 250 years, nearly 50% of the study area burned during two fire conflagrations, i.e., around 1815 and in 1878. The fires triggered gradual changes in plant composition and forest structure, as shown by a succession of forest types ranging from white birch ( Betula papyrifera Marsh.) to spruce–fir types. Absence of surficial charcoal older than 300 years suggests that high-altitude forests of the RFL area were not subjected to a constant fire regime. It is possible that recent fires were caused by human activity.
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CHAKRABARTI, SANTABHANU, and MARC DEYELL. "Friendly Fire During RF: Be Firm But Gentle!" Journal of Cardiovascular Electrophysiology 27, no. 3 (January 13, 2016): 296–97. http://dx.doi.org/10.1111/jce.12894.
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Turner, Monica, William Romme, Brian Harvey, and Daniel Donato. "Bark Beetles, Fuels, and Short-Interval Fires in Douglas-Fir and Lodgepole Pine Forests of Greater Yellowstone." UW National Parks Service Research Station Annual Reports 34 (January 1, 2011): 161–65. http://dx.doi.org/10.13001/uwnpsrc.2011.3889.
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Recent increases in insect and fire activity throughout the western US have presented forest managers with formidable challenges. The extent and severity of bark beetle (Curculionidae: Scolytinae) epidemics have reached unprecedented levels, and the frequency of large, severe fires continues to increase. These trends are expected to continue because climate change is implicated for both disturbances. Insects and fire have tremendous ecological and economic effects in western forests, yet surprisingly little is known about how fire hazard may change following bark beetle epidemics, and how changing fire regimes may potentially alter forests of Greater Yellowstone. We are employing a combination of field studies, remote sensing and simulation modeling to understand how bark beetle infestation affects fire hazard in Douglas-fir (Pseudotsuga menziesii) forests. The Douglas-fir type is a key component of Rocky Mountain landscapes, and is experiencing extensive and severe bark beetle outbreaks. However, almost no studies have examined Douglas-fir. We hypothesized that differences in fire regime, stand structure, regeneration potential and decomposition of woody fuels lead to important differences in fuel profiles, fire hazard and, in turn, the effectiveness of alternative mitigation strategies in Douglas-fir. Our studies are being conducted in Grand Teton and Yellowstone National Parks, and the Bridger-Teton and Shoshone National Forests within the Greater Yellowstone Ecosystem (GYE), where we build on >20 years of research and our recent studies of bark beetles and fire in lodgepole pine forests. During the summer of 2011, we conducted a significant portion of the field component of the project, collecting ancillary data in our previously measured chronosequence of Douglas-fir forests of differing time since beetle attack (TSB), and measuring burn severity and forest regeneration following a 2008 fire that burned a recently beetle-attacked Douglas-fir forest on the Shoshone National Forest. We also sampled forest regeneration and dead wood biomass following a short (28-year) interval âreburnâ in lodgepole pine forests to test whether reduced seed sources associated with younger trees at the time of burning might reduce postfire regeneration potential. Data analyses are ongoing and results will be forthcoming.
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Leung, Ting-Kai, Huey-Fang Shang, Dai-Chian Chen, Jia-Yu Chen, Tsong-Min Chang, Sheng-Yi Hsiao, Cheng-Kun Ho, and Yung-Sheng Lin. "EFFECTS OF FAR INFRARED RAYS ON HYDROGEN PEROXIDE-SCAVENGING CAPACITY." Biomedical Engineering: Applications, Basis and Communications 23, no. 02 (April 2011): 99–105. http://dx.doi.org/10.4015/s1016237211002414.
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Far infrared rays (FIRs) have several proven effects on the human body and are generally considered to be biologically beneficial. In this study, we determined the effect of FIRs on hydrogen peroxide (H2O2) -scavenging activity, which was directly increased by 10.26% after FIR application. Even in the indirect use of FIRs accompanying carrot extract, FIRs still contributed to a 5.48% increase in H2O2 -scavenging activity. We further proved that additional FIR treatment resulted in about 23.02% and 18.77% viability increases of osteoblast cells in the 200 and 800 μM H2O2 , respectively; and about 25.67% and 47.16% viability increases of fibroblast cells in the 25 and 50 μM H2O2 , respectively. Finally, FIR treatment also delayed senescence of detached Railway Beggarticks leaves in H2O2 solution with the concentrations of 10, 100, and 1000 μM. By reviewing past articles related to the effects of oxidative stress from metabolically produced H2O2 , we discuss possible benefits of FIRs for plants and animals.
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Kohlhase, Janet E., and Xiahong Ju. "Firm Location in a Polycentric City: The Effects of Taxes and Agglomeration Economies on Location Decisions." Environment and Planning C: Government and Policy 25, no. 5 (October 2007): 671–91. http://dx.doi.org/10.1068/c0649.
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The authors explore the determinants of firm location in a polycentric city with the aid of data for the Houston region. Firm location is modeled in a discrete-choice framework, with eight employment centers and outlying areas used as possible choices. Agglomerative and dispersive forces are explicitly treated, as are taxes and other characteristics that vary over space. The findings suggest that property taxes have large deterrent effects on firm locations for the four industrial groups analyzed here: oil and gas; manufacturing; finance, insurance and real estate (FIRE); and services. When agglomeration economies are present, they are weaker than the tax effects and are positive for only the FIRE and services industrial groups.
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Agee, James K., Mark Finney, and Roland De Gouvenain. "Forest fire history of Desolation Peak, Washington." Canadian Journal of Forest Research 20, no. 3 (March 1, 1990): 350–56. http://dx.doi.org/10.1139/x90-051.
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Forests in the vicinity of Desolation Peak, Washington, are of special ecological interest because of their transitional nature between coastal and interior forest types. The area is west of the Cascade Mountain crest but in the rainshadow of mountains farther to the west. Fire return intervals were hypothesized to be shorter than typical for coastal forest types, such as those dominated by western hemlock and Pacific silver fir, and longer than typical for interior forest types, such as ponderosa pine, owing to the close juxtaposition of these types at Desolation Peak. Seven forest community types were defined, and a 400-year fire history was developed for this 3500-ha area. The average natural fire rotation was 100 years; this varied by a factor of two by century and by topographic aspect. Forest types typical of coastal regions, such as Douglas-fir, – western hemlock and mountain hemlock – Pacific silver fir, had mean fire return intervals (108–137 years) much lower than in other western Washington areas. The most interior forest type, ponderosa pine – Douglas-fir, had a higher mean fire return interval (52 years) than reported for similar forest types east of the Cascades. Historically, fire has created structural and landscape diversity on Desolation Peak and may be an important process in the maintenance of such diversity into the future.
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Turner, Monica, Jacob Griffin, Philip Townsend, Martin Simard, Brian Harvey, Daniel Donato, and William Romme. "Bark Beetles, Fuels, Fire Potential and Nitrogen Cycling in Contrasting Conifer Forests of Greater Yellowstone." UW National Parks Service Research Station Annual Reports 33 (January 1, 2011): 171–76. http://dx.doi.org/10.13001/uwnpsrc.2011.3817.
Full textAbstract:
Recent increases in insect and fire activity throughout the western US have presented forest managers with formidable challenges. The extent and severity of bark beetle (Curculionidae: Scolytinae) epidemics have reached unprecedented levels, and the number of large, severe fires continues to increase. These trends are expected to continue because climate change is implicated for both disturbances. Insects and fire have tremendous ecological and economic effects in western forests, yet surprisingly little is known about how fire hazard may change following bark beetle epidemics, and the efficacy of alternative forest management practices (e.g., removal of beetle-killed trees or remaining small trees) designed to reduce future fire hazard is largely unknown. We are employing a combination of field studies, remote sensing and simulation modeling to understand how bark beetle infestation affects fire hazard in two widespread but contrasting forest types, lodgepole pine (Pinus contorta) and Douglas-fir (Pseudotsuga menziesii). Lodgepole pine and Douglas-fir forests are key components of Rocky Mountain landscapes, and both are experiencing extensive and severe bark beetle outbreaks. Published research on beetle effects on fire in lodgepole pine forests is inconclusive, and almost no studies have examined Douglas-fir. We hypothesize that differences in fire regime, stand structure, regeneration potential and decomposition of woody fuels lead to important differences in fuel profiles, fire hazard and, in turn, the effectiveness of alternative mitigation strategies in lodgepole pine and Douglas-fir. We also anticipate that ecosystem responses, especially nitrogen cycling, to beetle attack will differ between these two forest types. Our studies are being conducted in Grand Teton and Yellowstone National Parks, and the Bridger-Teton and Shoshone National Forests within the Greater Yellowstone Ecosystem (GYE), where we build on >20 years of research and our recent studies of bark beetles and fire in lodgepole pine forests. During the summer of 2010, we conducted a significant portion of the field component of the project, measuring stand structure and fuel profiles in a chronosequence of Douglas-fir forests of differing time since beetle attack (TSB), and also measuring burn severity and forest regeneration following a 2008 fire that burned a recently beetle-attacked forest. Data analyses are ongoing and results will be forthcoming.
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Stocks, B. J. "Fire Potential in the Spruce Budworm-damaged Forests of Ontario." Forestry Chronicle 63, no. 1 (February 1, 1987): 8–14. http://dx.doi.org/10.5558/tfc63008-1.
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An experimental burning program was carried out in Ontario between 1978 and 1982 to document quantitatively fire behavior in balsam fir killed by spruce budworm. Forest fire potential in budworm-killed balsam fir stands was shown to be significantly higher for a number of years following stand mortality. Crown breakage and windthrow, with resultant fuel complex rearrangement and increased surface fuel loads, peaked 5-8 years after mortality. Fire potential was greatest during this period, decreased gradually as balsam fir surface fuels began to decompose and understory vegetation proliferated. Fires occurring prior to "green-up" in the spring behaved explosively with continuous crowning, high spread rates, and severe problems with downwind spot fires. Summer fires in this fuel type did not spread at all in the early years following mortality; however, sufficient woody surface fuel accumulation 4-5 years after mortality permitted summer fire spread
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Hood, Sharon, and Barbara Bentz. "Predicting postfire Douglas-fir beetle attacks and tree mortality in the northern Rocky Mountains." Canadian Journal of Forest Research 37, no. 6 (June 2007): 1058–69. http://dx.doi.org/10.1139/x06-313.
Full textAbstract:
Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) were monitored for 4 years following three wildfires. Logistic regression analyses were used to develop models predicting the probability of attack by Douglas-fir beetle ( Dendroctonus pseudotsugae Hopkins, 1905) and the probability of Douglas-fir mortality within 4 years following fire. Percent crown volume scorched (crown scorch), cambium injury, diameter at breast height (DBH), and stand density index for Douglas-fir were most important for predicting Douglas-fir beetle attacks. A nonlinear relationship between crown scorch and cambium injury was observed, suggesting that beetles did not preferentially attack trees with both maximum crown scorch and cambium injury, but rather at some intermediate level. Beetles were attracted to trees with high levels of crown scorch, but not cambium injury, 1 and 2 years following fire. Crown scorch, cambium injury, DBH, and presence/absence of beetle attack were the most important variables for predicting postfire Douglas-fir mortality. As DBH increased, the predicted probability of mortality decreased for unattacked trees but increased for attacked trees. Field sampling suggested that ocular estimates of bark char may not be a reliable predictor of cambium injury. Our results emphasize the important role of Douglas-fir beetle in tree mortality patterns following fire, and the models offer improved prediction of Douglas-fir mortality for use in areas with or without Douglas-fir beetle populations.
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Taylor, K. L., and R. W. Fonda. "Woody fuel structure and fire in subalpine fir forests, Olympic National Park, Washington." Canadian Journal of Forest Research 20, no. 2 (February 1, 1990): 193–99. http://dx.doi.org/10.1139/x90-027.
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The fuel structure and flammability of subalpine fir (Abieslasiocarpa (Hook.) Nutt.) stands were studied to determine the relationship between these forests and fire. It has long been known that subalpine fir forests burn catastrophically, but the contributions of fuel structure and fuel moisture to this pattern of burning have been relatively unstudied. This investigation discovered two relationships. First, over twice as much fuel in subalpine fir forests accumulated around the bases of the fir trees than in the forest as a whole, and the many dead branches on the lower trunks may allow fire to travel up into the canopy. Second, the fuels in subalpine fir forests were more flammable at the end of the summer than at the beginning, and maximum flammability was achieved in early August when the fuel moisture was between 16 and 22%. We also found that the fuel structure of subalpine fir was different from that of fire-stable ponderosa pine (Pinusponderosa Laws.) forests. The fuel around the bases of the trees in ponderosa pine forests was not significantly different from that in the entire forest, and there were few branches on the lower trunks.
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Schaupp, Willis C. "HOST ASSOCIATIONS IN SYMPATRIC POPULATIONS OF CHORISTONEURA OCCIDENTALIS FREEMAN AND C. RETINIANA (WALSINGHAM) (LEPIDOPTERA: TORTRICIDAE) IN SOUTH-CENTRAL OREGON AT HIGH POPULATION DENSITIES." Canadian Entomologist 123, no. 3 (June 1991): 713–15. http://dx.doi.org/10.4039/ent123713-3.
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Sympatric, synchronous populations of conifer-feeding Choristoneura (Lepidoptera: Tortricidae) occur in western North America (Powell 1980). Choristoneura occidentalis Freeman, the western spruce budworm, co-exists with C. retiniana, the Modoc budworm, in mixed stands of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, and true firs, Abies spp. Choristoneura occidentalis has brown larvae and a broad geographic distribution associated with one of its principle hosts, Douglas-fir (Stehr 1967). Larvae of C. retiniana are green and feed on true firs, particularly white fir, Abies concolor (Gord. & Glend.) Lindl. (Stehr 1967; Carolin et al. 1987).
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Ferrell, G. T., W. J. Otrosina, and C. J. DeMars. "ASSESSING THE SUSCEPTIBILITY OF WHITE FIR TO THE FIR ENGRAVER, SCOLYTUS VENTRALIS LEC. (COLEOPTERA: SCOLYTIDAE), USING FUNGAL INOCULATION." Canadian Entomologist 125, no. 5 (October 1993): 895–901. http://dx.doi.org/10.4039/ent125895-5.
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AbstractA method of assessing susceptibility of white fir, Abies concolor (Gord. and Glend.) Lindl., by fungal inoculation was tested during an outbreak of the fir engraver beetle, Scolytus ventralis LeC., at Lake Tahoe, California, in 1987 through 1989. A total of 592 firs growing in six forest stands containing trees infested by the beetle were inoculated with the mutualistic fungus, Trichosporium symbioticum Wright. Six weeks later, reaction wounds were characterized by vertical length and resin concentration. After 2 years, 196 (33.1%) of the test firs had been killed by the beetle. Reaction lengths tended to be greater and resin concentrations lower in test firs that died than in those that survived, but predictive accuracy of the wound variables was inadequate on either an individual tree or a stand basis. On an individual tree basis, discriminant functions using either or both of these reaction wound variables as predictors produced overall percentages of correct classification little higher than would be obtained by predicting that all test firs would survive. On a stand basis, regression models using stand means for the wound variables and white fir basal area as predictors statistically explained more than 95% of observed variation in basal area of white fir killed, but another model using only basal area of white fir as a predictor performed nearly as well.
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Taylor, Alan H. "Fire history and structure of red fir (Abiesmagnifica) forests, Swain Mountain Experimental Forest, Cascade Range, northeastern California." Canadian Journal of Forest Research 23, no. 8 (August 1, 1993): 1672–78. http://dx.doi.org/10.1139/x93-208.
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The fire history and stand structure (size, age, horizontal pattern) of red fir (Abiesmagnifica A. Murr) forests were studied in two 3.0-ha plots and a larger study area (400 ha) on the Swain Mountain Experimental Forest to identify the fire regime and the effects of fire on stand structure. The fire record in stumps spanned the period 1740–1985. Fires occurred in the 400-ha study area on average every 12.9 years (range 1–57 years), in plot 1 every 18.6 years (range 7–47 years), and in plot 2 every 15.7 years (range 1–45 years). Larger fires recorded in both plots and throughout the larger study area occurred every 26.2 years (range 11–47 years). Average fire-free intervals were shorter (7.9 years) during the settlement–pre-fire-sup-pression period (1851–1934) than during the presettlement (1740–1850) (21.4 years) and fire-suppression (1935–1985) (17.3 years) periods. Severe fires initiated large cohorts of red and white fir (Abiesconcolor (Gord. & Glend.) Lindl.), while low-severity fires probably caused thinning and initiated small patches of trees.
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Hadfield, James S., and Paul T. Flanagan. "Dwarf Mistletoe Pruning May Induce Douglas-Fir Beetle Attacks." Western Journal of Applied Forestry 15, no. 1 (January 1, 2000): 34–36. http://dx.doi.org/10.1093/wjaf/15.1.34.
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Abstract Fresh attacks of Douglas-firs (Pseudotsuga menziesii) by Douglas-fir beetles (Dendroctonus pseudotsugae) were found in a campground that had trees pruned to remove Douglas-fir dwarf mistletoe (Arceuthobium douglasii) infections. All Douglas-firs with a diameter at breast height (dbh) of at least 12.7 cm were examined. Beetle attacks were found on 41% of the pruned trees and 5% of the unpruned trees. Among pruned trees, both the average number of branches pruned and the average dbh were greater in trees attacked by Douglas-fir beetles than in unattacked trees. West. J. Appl. For. 15(1):34-36.
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Heyerdahl, Emily K., Rachel A. Loehman, and Donald A. Falk. "A multi-century history of fire regimes along a transect of mixed-conifer forests in central Oregon, U.S.A." Canadian Journal of Forest Research 49, no. 1 (January 2019): 76–86. http://dx.doi.org/10.1139/cjfr-2018-0193.
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Dry mixed-conifer forests are widespread in the interior Pacific Northwest, but their historical fire regimes are poorly characterized, in particular the relative mix of low- and high-severity fire. We reconstructed a multi-century history of fire from tree rings in dry mixed-conifer forests in central Oregon. These forests are dominated by ponderosa pine (Pinus ponderosa Lawson & C. Lawson), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), and grand fir (Abies grandis (Douglas ex D. Don) Lindl.). Across four, 30-plot grids of ∼800 ha covering a mosaic of dry mixed-conifer forest types, we sampled 4065 trees for evidence of both high- and low-severity fire. From 1650 to ∼1900, all four sites sustained frequent, often extensive, low-severity fires that sometimes included small patches of severe fire (50–150 ha during 18%–28% of fire years). Fire intervals were similar among sites and also among forest types within sites (mean intervals of 14–32 years). To characterize the continuous nature of the variation in fire severity, we computed a plot-based index that captures the relative occurrence of low- and high-severity fire. Our work contributes to the growing understanding of variation in past fire regimes in the complex and dynamic forests of North America’s Interior West.
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Gill, Nathan S., Daniel Jarvis, John Rogan, and Dominik Kulakowski. "Disturbance history modulates how litter and herbaceous cover influence conifer regeneration after fire." International Journal of Wildland Fire 29, no. 6 (2020): 519. http://dx.doi.org/10.1071/wf19028.
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Climate-driven increases in disturbance frequency and extent augment the potential for compounded disturbances. Drawing on well-studied forests that experienced successive disturbances, we asked: (1) how does post-fire cover of litter, herbaceous cover and bare ground vary between stands affected by combinations of blow-down, insect outbreak, and fire? (2) How do post-fire relationships between ground cover and conifer regeneration vary with recent disturbance history? We measured ground cover and conifer regeneration from 2003 to 2014 following stand-replacing fires in 2002. Burned stands were either blown down in 1997, affected by a 1940s Dendroctonus rufipennis (spruce beetle; SB) outbreak, or neither. Implementing mixed-effects models, we measured the relationships between pre-fire stand attributes (structural stage, canopy dominance and combination of disturbances) and post-fire ground cover and between post-fire ground cover and conifer regeneration. Fire-only stands had more litter and herbaceous cover post fire than other stands (P<0.05). Fir regeneration increased with litter in stands that only burned, but decreased with litter in stands that were first blown down. Similarly, pine and fir regeneration increased with herbaceous cover after fire-only, but did the opposite in stands affected by the SB outbreak. Pre-fire legacies can modulate the effects of ground cover on plant regeneration.
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Renkin, Roy A., and Don G. Despain. "Fuel moisture, forest type, and lightning-caused fire in Yellowstone National Park." Canadian Journal of Forest Research 22, no. 1 (January 1, 1992): 37–45. http://dx.doi.org/10.1139/x92-005.
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The occurrence and behavior of lightning-caused fires in Yellowstone National Park were summarized for 17 years (1972–1988) during a prescribed natural fire program. Both ignition (occurrence) and spread (stand replacing fire activity) of fires were strongly influenced by fuel moisture and forest cover type. Fuel moisture estimates of 13% for large (>7.6 cm) dead and downed fuels indicated a threshold below which proportionately more fire starts and increased stand replacing fire activity were observed. During periods of suitable fuel moisture conditions, fire occurrence and activity were significantly greater than expected in old-growth, mixed-canopy lodgepole pine (Pinuscontorta Dougl. var. latifolia) and Engelmann spruce–subalpine fir (Piceaengelmannii Parry–Abieslasiocarpa (Hook.) Nutt.) forest types, and significantly less than expected in the successional lodgepole pine forest types. During periods of extended low fuel moisture conditions (drought), sustained high winds significantly reduced the influence of forest cover type on stand replacing fire activity. These extreme weather conditions were observed during the later stages of the 1988 fire season, and to a lesser extent, for a short duration during the 1981 fire season. The Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) forest type typically supported little stand replacing fire activity, even though a preponderance of fire starts was observed.
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Hoffman, Kira M., Sara B. Wickham, William S. McInnes, and Brian M. Starzomski. "Fire Exclusion Destroys Habitats for At-Risk Species in a British Columbia Protected Area." Fire 2, no. 3 (August 29, 2019): 48. http://dx.doi.org/10.3390/fire2030048.
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Fire exclusion and suppression has altered the composition and structure of Garry oak and associated ecosystems in British Columbia. The absence of frequent low severity ground fires has been one of the main contributors to dense patches of non-native grasses, shrubs, and encroaching Douglas-fir trees in historical Garry oak dominated meadows. This case study uses remote sensing and dendrochronology to reconstruct the stand dynamics and long-term fire history of a Garry oak meadow situated within Helliwell Provincial Park located on Hornby Island, British Columbia. The Garry oak habitat in Helliwell Park has decreased by 50% since 1950 due to conifer encroachment. Lower densities and mortalities of Garry oak trees were associated with the presence of overstory Douglas-fir trees. To slow conifer encroachment into the remaining Garry oak meadows, we recommend that mechanical thinning of Douglas-fir be followed by a prescribed burning program. Reintroducing fire to Garry oak ecosystems can restore and maintain populations of plants, mammals, and insects that rely on these fire resilient habitats.
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Ferrell, G. T., W. J. Otrosina, and C. J. Demars Jr. "Predicting susceptibility of white fir during a drought-associated outbreak of the fir engraver, Scolytusventralis, in California." Canadian Journal of Forest Research 24, no. 2 (February 1, 1994): 302–5. http://dx.doi.org/10.1139/x94-043.
Full textAbstract:
Phenotypic traits were compared with a vigor (growth efficiency) index for accuracy in predicting susceptibility of white fir, Abiesconcolor (Gord. & Glend.) Lindl., during a drought-associated outbreak of the fir engraver, Scolytusventralis LeC., in the central Sierra Nevada at Lake Tahoe, California. Predictor variables were estimated for 633 firs in six forest stands in 1987. After 2 years, virtually all of the trees had been attacked by the beetle, and 230 (36.3%) had been killed or were dying. In all of the predictor variables, firs that were killed differed significantly from those that survived. Compared with survivors, firs that died averaged shorter, more ragged crowns and lower growth efficiencies. Also, firs that died were more frequently dominant or codominant in the stand canopy and, when characterized in 1987, more often evidenced signs of being under current or recent (in 1985 or 1986) attack by the beetles. But, on either an individual tree or a stand basis, predictive accuracy was inadequate. On an individual tree basis, discriminant functions using either the phenotypic traits or vigor index as predictors produced overall percentages of correct classification little or no higher than would be obtained by predicting all trees would survive. On a stand basis, regression models using stand means for either the phenotypic traits or vigor index and white fir basal area as predictors statistically accounted for at least 95% of observed variation in basal area of white fir killed. But another model, using only white fir basal area, performed as well. The "best" model, containing white fir basal area and total stand basal area, accounted for over 98% of observed variation.
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Takahashi, Satoko, Y. Shimajiri, S. Takakuwa, M. Saito, and R. Kawabe. "Survey observations of large-scale molecular outflows associated with intermediate-mass protostar candidates in the OMC-2/3 region." Proceedings of the International Astronomical Union 2, S237 (August 2006): 479. http://dx.doi.org/10.1017/s1743921307002670.
Full textAbstract:
AbstractWe have newly performed millimeter- and submillimeter-wave observations in the nearest GMC: the Orion Molecular Cloud -2/3 region (OMC-2/3). Here, we report results of our large-scale (22' × 14') outflow survey with the Atacama Submillimeter Telescope Experiment (ASTE) in the CO(3-2) emission. The OMC-2/3 region is one of the famous intermediate-mass star-forming regions and harbors several sources diagnosed as Class0 protostars (Chini et al. 1997). With the intensive ASTE observations, we totally identified the 8 clear, 5 probable and 6 marginal outflows in OMC-2/3. 8 clear outflows from them, MMS 2, MMS 5, MMS7, MMS9, FIR-2, FIR 3, VLA 13, and FIR 6b are associated with mm and SPITZER 24 μm sources. The others are more or less complicated, and two of which, VLA 13 and FIR 6, are newly identified. We found the interaction between the molecular outflows and the dust condensations at least in four regions. In addition, we confirmed the increment of the velocity width of the dense gas toward some of these condensations (i.e. at the termination of the outflow lobes). These results suggest that (i) the interaction between the outflows and the dense condensation occurs commonly in the OMC-2/3 region, (ii) the dense condensations in this region are compressed ubiquitously by these outflows and are receiving a part of the momentum from them. Particularly, one of the strongest millimeter sources, and hence protostar candidates, FIR4, is strongly compressed by a molecular outflow driven by FIR3 located at the north-east of FIR 4. These results suggest that the molecular outflows play an important role in the formation and evolution of stars and that the outflows are a driving mechanism of turbulence in the OMC-2/3 region.
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Antos, Joseph A., and Roberta Parish. "Dynamics of an old-growth, fire-initiated, subalpine forest in southern interior British Columbia: tree size, age, and spatial structure." Canadian Journal of Forest Research 32, no. 11 (November 1, 2002): 1935–46. http://dx.doi.org/10.1139/x02-116.
Full textAbstract:
We used dendrochronological analysis of over 2000 trees in four 50 × 50 m plots to reconstruct the history and dynamics of a 330-year-old, fire-initiated spruce-fir forest. All lodgepole pine (Pinus contorta Dougl. ex Loud.), half of the canopy Engelmann spruce (Picea engelmannii Parry ex Engelm.), but less than 10% of the canopy subalpine fir (Abies lasiocarpa (Hook.) Nutt.) dated from the first 50 years of stand development. Tree-ring patterns of individual surviving trees showed no evidence of disturbance during the first 200 years after stand initiation; subsequently, episodes of disturbance are indicated by periods of release in understory fir. Although many fir owe their canopy position to release after disturbance, few canopy fir in the current stand established in response to either the stand-initiating event or subsequent partial disturbances. A seedling bank of long-lived fir appears critical to the dynamics of this forest. In contrast, establishment of almost all canopy spruce can be related to disturbance. This stand, although fire initiated, was structured primarily by a combination of partial disturbances and autogenic processes. We suspect that most old, fire-initiated stands in many forest regions are similarly structured and emphasize that the contribution of partial disturbances and autogenic processes should be fully assessed when examining their dynamics or managing such forests.
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Krause, Cornelia, and Hubert Morin. "Changes in radial increment in stems and roots of balsam fir [Abies balsamea (L.) Mill.] after defoliation spruce budworm." Forestry Chronicle 71, no. 6 (December 1, 1995): 747–54. http://dx.doi.org/10.5558/tfc71747-6.
Full textAbstract:
Radial increment along the stems and the root systems of 20 balsam fir (Abies balsamea Mill.) was analysed as an indicator of resource allocation after a spruce budworm outbreak. The trees were located in a natural forest, 130 km north of Lake Saint Jean (Québec) in the boreal forest zone. The dynamics of the forest were determined by fire and insect outbreaks. The 20 analysed firs showed clear signs of the last two spruce budworm outbreaks. Tree-ring width was reduced one year earlier in the crown region than at the stem base, and was more variable in the root system. Many tree-rings were missing at the stem base section and especially in the root system (2099 missing rings). Recovery started with a time delay of one year from the upper part of the crown and continued downwards in the stem. The roots and the crown recovered within a longer period. Key words: Abies balsamea, Choristoneura fumiferana, dendroecology, radial increment, root, spruce budworm
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Heyerdahl, Emily K., Ken Lertzman, and Carmen M. Wong. "Mixed-severity fire regimes in dry forests of southern interior British Columbia, Canada." Canadian Journal of Forest Research 42, no. 1 (January 2012): 88–98. http://dx.doi.org/10.1139/x11-160.
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Historical fire severity is poorly characterized for dry forests in the interior west of North America. We inferred a multicentury history of fire severity from tree rings in Douglas-fir ( Pseudotsuga menziesii var. glauca (Beissn.) Franco) – ponderosa pine ( Pinus ponderosa Douglas ex P. Lawson & C. Lawson) forests in the southern interior of British Columbia, Canada. In 2 ha plots distributed systematically over 1105 ha, we determined the dates of fire scars, indicators of low-severity fire, from 125 trees and inferred dates of even-aged cohorts, potential indicators of high-severity fire, from establishment dates of 1270 trees. Most (76%) of the 41 plots contained fire-scarred trees with a mean plot-composite fire scar interval of 21 years (1700–1900). Most (76%) also contained one or two cohorts. At the plot scale, we inferred that the fire regime at most plots was of mixed severity through time (66%) and at the remaining plots of low (20%), high (10%), or unknown (4%) severity through time. We suggest that across our study area, the fire regime was mixed severity over the past several centuries, with low-severity fires most common and often extensive but small, high-severity disturbances also occasionally occurred. Our results present strong evidence for the importance of mixed-severity fire regimes in which low-severity fires dominate in interior Douglas-fir – ponderosa pine forests in western Canada.
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Archambault, Louis, Jacques Morissette, and Michèle Bernier-Cardou. "Succession forestière après feu dans la sapinière à bouleau jaune du Bas-Saint-Laurent, Québec." Forestry Chronicle 73, no. 6 (December 1, 1997): 702–10. http://dx.doi.org/10.5558/tfc73702-6.
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Forest successions following a forest fire that occurred in 1932 were studied on mesic sites of the boreal mixedwood forest of the Bas-Saint-Laurent region of Quebec, Canada. Physiographic, soil and vegetation data were collected in 28 ecosystems distributed on a topographic gradient. The vegetation composition of the main canopy, 64 years after the fire, varied according to topographic situation. The proportion of tolerant hardwood species (yellow birch (Betula alleghaniensis Britton), sugar maple (Acer saccharum Marsh.), red maple (Acer rubrum L.)) increased toward upper slopes whereas it was the opposite for coniferous species (white spruce (Picea glauca [Moench] Voss), balsam fir (Abies balsamea [L.] Mill.)), as their proportion increased toward lower slopes. Intolerant hardwood species (white birch (Betula papyrifera Marsh.), trembling aspen (Populus tremuloides Michx.)) were abundant in all ecosystems. The distribution pattern of regeneration density and stocking of tolerant hardwoods and conifers was similar to that of the main canopy. The majority of commercial species, including tolerant species, established rapidly after the fire. Only eastern white cedar (Thuya occidentalis L.), which is a species typical of late succession, did not grow back. Ten years after the fire, 78% of the sampled dominant trees were established. Competition caused by mountain maple (Acer spicatum Lam.) did not seem to be as important after fire compared with the situation after clearcutting. Results showed that after the elimination of intolerant species, the vegetation composition should evolve toward the potential vegetation (climax) of the toposequence, that is, the sugar maple - yellow birch type on upper slopes, the balsam fir - yellow birch type on midslopes and the balsam fir - yellow birch - cedar type on lower slopes. Key words: succession, fire, yellow birch, balsam fir, mountain maple.
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van Mantgem, Phillip J., Anthony C. Caprio, Nathan L. Stephenson, and Adrian J. Das. "Forest Resistance to Extended Drought Enhanced by Prescribed Fire in Low Elevation Forests of the Sierra Nevada." Forests 12, no. 9 (September 15, 2021): 1248. http://dx.doi.org/10.3390/f12091248.
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Prescribed fire reduces fire hazards by removing dead and live fuels (small trees and shrubs). Reductions in forest density following prescribed fire treatments (often in concert with mechanical treatments) may also lessen competition so that residual trees might be more likely to survive when confronted with additional stressors, such as drought. The current evidence for these effects is mixed and additional study is needed. Previous work found increased tree survivorship in low elevation forests with a recent history of fire during the early years of an intense drought (2012 to 2014) in national parks in the southern Sierra Nevada. We extend these observations through additional years of intense drought and continuing elevated tree mortality through 2017 at Sequoia and Kings Canyon National Parks. Relative to unburned sites, we found that burned sites had lower stem density and had lower proportions of recently dead trees (for stems ≤47.5 cm dbh) that presumably died during the drought. Differences in recent tree mortality among burned and unburned sites held for both fir (white fir and red fir) and pine (sugar pine and ponderosa pine) species. Unlike earlier results, models of individual tree mortality probability supported an interaction between plot burn status and tree size, suggesting the effect of prescribed fire was limited to small trees. We consider differences with other recent results and discuss potential management implications including trade-offs between large tree mortality following prescribed fire and increased drought resistance.
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Debkov, Nikita M., Aleksey A. Aleinikov, Alexander Gradel, Anatoly Yu Bocharov, Nina V. Klimova, and Gennady I. Pudzha. "Impacts Of The Invasive FourEyed Fir Bark Beetle (Polygraphus Proximus Blandf.) On Siberian Fir (Abies Sibirica Ledeb.) Forests In Southern Siberia." GEOGRAPHY, ENVIRONMENT, SUSTAINABILITY 12, no. 3 (October 3, 2019): 79–97. http://dx.doi.org/10.24057/2071-9388-2019-35.
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The emergence and spread of non-native invasive forest insects represent a major potential threat to global biodiversity. The present study examines the current invasion of the far eastern four-eyed fir bark beetle Polygraphus proximus Blandf. in southern Siberian fir (Abies sibirica Ledeb.) forests. We collected data on 38 large sized (2500 m²) sample plots, situated in fir forests of the Tomsk region. As a direct result of the four-eyed fir bark beetle infestation, stand density decreased by 34-37%, and stand volume by 30%. The mean height, individual age and diameter at the stand level consequently increased. Our results indicated that stands with complete left-sided or normal ontogenetic structure (composed primarily of late virginal firs or firs in young reproductive stage) are more resistant to invasion by the four-eyed fir bark beetle. By contrast, fir forests characterized by more right-sided ontogenetic structure (composed primarily of mature and old reproductive firs), exhibited the least resistance and, with rare exception, degraded rapidly in response to the invasion. Our results also pointed to a mechanism that initiates invasions of the four-eyed fir bark beetle in fir stands of all types of ontogenetic structure, which is the attack of virginal trees and trees in early reproductive stages. Trees up to average diameter are the most susceptible to invasions of the bark beetle. We identified thicker bark, larger DBH and low occurrence of heart rot as the most important parameters for indicating resistance at the single tree level. DBH and bark thickness (p<0.05) correlated significantly with tree health status in infested stands. Our overall assessment of the potential natural regeneration of damaged stands is that the Siberian fir forests are resilient to invasive species and that the fir ecosystems can potentially recover from this disturbance.
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Hawkins, Ashley E., and Terry W. Henkel. "Native forest pathogens facilitate persistence of Douglas-fir in old-growth forests of northwestern California." Canadian Journal of Forest Research 41, no. 6 (June 2011): 1256–66. http://dx.doi.org/10.1139/x11-053.
Full textAbstract:
Forest pathogens and insects can accelerate tree mortality, increase stand structural heterogeneity, and alter tree community composition. In northern California, the canopy trees Abies concolor var. lowiana (Gord. & Glend.) Lemmon (white fir) and Pseudotsuga menziesii var. menziesii (Mirbel) Franco (Douglas-fir) co-occur but vary in shade tolerance and regenerative abilities following disturbance. Field observations suggested that mortality and turnover of white fir exceeded that of Douglas-fir and that native pathogens may be important drivers in the absence of fire. Pathogens and bark beetles were sampled in old-growth white fir – Douglas-fir stands in northwestern California to assess their contribution to tree mortality, gap formation, and regeneration. We determined abundances and size class distributions of canopy trees, presence of pathogens and bark beetles, and causes of tree mortality. We sampled canopy gaps and closed-canopy forests for overstory species composition, cause of mortality of gap-maker trees, and regeneration of white fir and Douglas-fir. Root-rot fungi accounted for significantly higher mortality and gap formation in white fir than in Douglas-fir. Relative seedling–sapling density of Douglas-fir was higher in pathogen-induced canopy gaps than in closed-canopy forest. In the absence of fire, native forest pathogens enable regeneration and persistence of Douglas-fir by enhancing mortality of white fir, resulting in canopy gap formation.
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Плаксицкий, A. Plaksitskiy, Кочегаров, Aleksey Kochegarov, Логачев, and O. Logachev. "OPTIMIZATION OF ARRIVAL FIRE DEPARTMENTS IN THE URBAN ENVIRONMENT." Alternative energy sources in the transport-technological complex: problems and prospects of rational use of 2, no. 2 (December 17, 2015): 771–75. http://dx.doi.org/10.12737/19561.
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The paper presents the results of mathematical modeling algorithms are many alternative routing arrival of fire trucks in the urban district. The constructed model can be effectively applied in modern conditions when planning design fire stations and forecast situation on the ground fir