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1
Schmid, Amy V. "Coarse Woody Debris and the Carbon Balance of a Moderately Disturbed Forest." VCU Scholars Compass, 2015. http://scholarscompass.vcu.edu/etd/3777.
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Landscapes are comprised of multiple ecosystems shaped by disturbances varying in severity and source. Moderate disturbance from weather, pathogens, insects, and age-related senescence, in contrast to severe disturbances that fell trees, may increase standing woody debris and alter the contribution of coarse woody debris (CWD) to total ecosystem respiration (RE). However, woody debris dynamics are rarely examined following moderate disturbances that substantially increase standing dead wood stocks. We used an experimental manipulation of moderate disturbance in an upper Great Lakes forest to: 1) examine decadal changes in CWD stocks through a moderate disturbance; 2) quantify in situ CWD respiration during different stages of decay for downed and standing woody debris and; 3) estimate the annual contribution of CWD respiration to the ecosystem C balance through comparison with RE and net ecosystem production (NEP). We found that the standing dead wood mass of 24.5 Mg C ha-1 was an order of magnitude greater than downed woody debris stocks and a large source of ecosystem C flux six years following disturbance. Instantaneous in situ respiration rates from standing and downed woody debris in the earliest stages of decay were not significantly different from one another. Independently derived estimates of ecosystem CWD respiration of 1.1to 2.1 Mg C ha-1 yr-1 six years following disturbance were comparable in magnitude to NEP and 12.5 % to 23.8 % of RE, representing a substantial increase relative to pre-disturbance levels. Ecosystem respiration and NEP were stable following moderate disturbance even though ecosystem CWD respiration increased substantially, suggesting a reduction in the respiratory C contribution from other sources. We conclude that CWD is an essential component of the ecosystem C balance following a moderate forest disturbance.
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Corrow, Allissa. "DOUBLE SAMPLING FOR COARSE WOODY DEBRIS ESTIMATIONS FOLLOWING LINE INTERSECT SAMPLING." The University of Montana, 2010. http://etd.lib.umt.edu/theses/available/etd-06122010-133739/.
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Coarse woody debris (CWD), an essential component of healthy forests, has typically been defined as dead and down, large woody material. Quantification of this resource provides a useful metric for assessing wildlife habitat, fuel loading, and more recently, carbon sequestration. Although many CWD sampling methods exist, accurate estimation is difficult and expensive. Double sampling incorporates auxiliary data that is positively correlated with the attribute of interest as a means of reducing sampling costs and/or increasing estimation precision. The present study investigated double sampling applications to the common CWD sampling technique, line intersect sampling (LIS). We identified aggregate length as a potential auxiliary variable for estimating aggregate volume and abundance of CWD. However, further analysis indicated that the cost difference of the sampling phases, coupled with the correlation of the variables was not sufficient to warrant double sampling in the study area. Further investigation is needed to develop accurate and efficient CWD sampling methods with widespread applicability.
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Woods, Michaela J. "Lonicera maackii alters decay dynamics of coarse woody debris." Wright State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=wright1544793080360437.
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Swanson, Mark Ellyson. "Measurement and modeling of the forest carbon resource in the Nothofagus forests of Tierra del Fuego, Chile /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/5491.
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Latterell, Joshua J. "The natural history and dynamics of large wood in the Queets River, Washington /." Thesis, Connect to this title online; UW restricted, 2005. http://hdl.handle.net/1773/5273.
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Boldor, Irina Angelica. "An assessment of the representation of fire severity and coarse woody debris dynamics in an ecosystem management model." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/914.
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Fire is the most significant natural disturbance agent in the MSdm biogeoclimatic subzone and has a determinant role in the dynamics of lodgepole pine (Pinus contorta ssp. latifolia Engelm.ex S.Wats.) dominated forests. Fire severity is a controversial term that usually refers to a qualitative measure of the fire effects on soil and vegetation and ultimately on ecosystem sustainability. The main objective of the thesis was to evaluate methods for quantifying and modelling the effects of fire severity on live biomass and dead organic matter and post-fire coarse woody debris (CWD) dynamics.
A review of the representation of fire in models was conducted and several of the most commonly used fire models in North America have been described in terms of fire severity representation. The potential for developing the fire severity concept as a fire effects descriptor in an ecosystem management model were assessed. Severity matrices summarizing the probabilities of occurrence for fires of varying severity were constructed for two sites in the MSdm biogeoclimatic subzone of British Columbia, using weather data and past fire records. These matrices provide information to improve fire representation in the ecosystem based model FORECAST by quantifying the effects of fire severity on dead and live biomass components. Although this represents only a preliminary step, the severity matrix approach appears toprovide a viable methodology for improving the representation of fire effects in FORECAST.
Patterns of post-fire coarse woody debris (CWD) accumulation were also assessed in the context of model development. Data were collected from a chronosequence of fire affected sites in the MSdm subzone of the TFL 49 Kelowna. The ability of the FORECAST model to simulate accumulation patterns in CWD and soil organic matter and nitrogen following fire was tested by comparing model outputs with field data. The evaluation of the model against chronosequence-derived data highlighted the fact that caution needs to be taken when using such data for model testing. The very slow recruitment pattern for new CWD illustrates the need to retain sources of CWD recruitment following fire by not salvage logging all killed trees and/or surviving live trees.
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Davis, Jessica G. "Spatiotemporal dynamics of coarse woody debris in a topographically complex, old-growth, deciduous forest." University of Dayton / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1405199554.
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Fox, Martin J. "Spatial organization, position, and source characteristics of large woody debris in natural systems /." Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/5463.
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Bold, Richard P. "Influence of coarse woody debris dams on leaf litter dynamics in U.K.headwater streams." Thesis, Coventry University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251857.
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Biswas, Suparna. "Coarse Woody Debris Pools and Fluxes in a Northern Deciduous Forest, Michigan, USA." The Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1395841859.
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Fuhrman, Nicholas E. "An Analysis of the Ecology and Public Perception of Coarse Woody Debris in Virginia." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/10012.
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Coarse woody debris (CWD) is an important habitat component for wildlife, fish, and plants and is important in nutrient cycling and soil formation. Knowledge of the volume, distribution, and use of CWD across Virginia would be useful to forest managers modeling nutrient budgets in southeastern forests and is important to wildlife management efforts. Knowledge of the effectiveness of informational brochures and cooperative learning activities/presentations at influencing public perception of CWD is important to program design and evaluation efforts in teaching and extension. The objectives of this study were to quantify the relationship between forest cover type and CWD volume, correlate CWD volume with small mammal and bird activity, distribute information on the advantages and disadvantages of CWD using informational brochures and cooperative learning activities/presentations, and compare the effectiveness of such teaching techniques at influencing public perception of CWD. The volume and wildlife use of CWD was assessed within 12 mature second-growth stands in Virginia. Volume of CWD was measured using fixed-area plots. Use of CWD by small mammals and birds was assessed by noting bodily, foraging, or movement evidence. Pre- and post-survey instruments were used to evaluate how perceptions were altered in first year college students who either reviewed an informational brochure or participated in a cooperative learning activity/presentation. Results suggested that the management of CWD for wildlife was most needed in southeastern Virginia where CWD volumes were lowest and that the value of CWD for wildlife was best conveyed through cooperative learning activities/presentations and may be important to landowner education efforts. Results suggested that management efforts to increase CWD volumes in Virginia should focus on coniferous dominated stands where CWD volumes were lowest. Such a finding, combined with the knowledge that the value of CWD was best conveyed through presentations, suggests that landowners of coniferous woodlots could be effectively educated with presentations. Given that brochures were more effective for females than males, brochures addressing natural resource issues might be the most appropriate, cost effective method of education at events that target female audiences. Knowledge gained from this study that CWD management for wildlife would be most appropriate in western Virginia where CWD was most used by wildlife for travel and that presentations were most effective at reaching suburban participants may be important to outreach program design efforts. Regardless of academic major, presentations were more effective at generating positive attitudes toward CWD. The results of this study suggest that the choice between informational brochures and presentations for influencing public perceptions of CWD will likely be influenced by the demographics of the target audience and the relevance of the topic locally.Master of Science
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Pittman, Judd R. "Coarse Woody Debris in Industrially Managed Pinus taeda Plantations of the Southeastern United States." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/34240.
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Coarse woody debris (CWD) plays an influential role in forested ecosystems by adding organic matter to soils, stabilizing the soil environment, providing wildlife habitat, preventing soil erosion, providing seedling establishment habitat, and involvement in the nutrient cycle. Most CWD research has been conducted in old-growth and unmanaged, second-growth forests. However, less is understood about CWD in intensively managed ecosystems, such as industrialized southern pine plantations. The objectives of this study were to determine the climatic and ecological factors that affect the decomposition rate of CWD, to predict the decomposition rate, specific gravity, and time since death (TSD) using multiple linear regression in industrial loblolly pine (Pinus taeda L.) plantations in the southeastern United States. The study sites for this project were part of a long-term, loblolly pine thinning study maintained by the Loblolly Pine Growth and Yield Research Cooperative at Virginia Tech. Measurements included piece size, position, and decay class. Samples of CWD were collected and analyzed to determine their mass and density. Decomposition rate of CWD was significantly different across position classes and decay classes: disk decomposition rates were significantly negatively correlated with disk diameter, large and small end piece diameter, estimated disk height, and disk dry weight. Average annual precipitation and average annual temperature were not significantly correlated with CWD disk decomposition rate.Master of Science
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Mcdonald, Shannon Lee. "Understory Diversity and Succession on Coarse Woody Debris in a Coastal, Old-growth Forest, Oregon." PDXScholar, 2013. https://pdxscholar.library.pdx.edu/open_access_etds/1045.
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This research examines the relationship between understory plant diversity and logs in a Pacific Northwest (PNW) Sitka spruce (Picea sitchensis)-western hemlock (Tsuga heterophylla) old-growth, coastal forest. These forests are renowned for their high forest productivity, frequent wind storms, and slow log decomposition rates that produce unmatched accumulations of coarse woody debris (CWD) yet few studies have examined the relationship between CWD and understory vegetation ecology. My research addressed this topic by comparing understory plant census data between paired fallen log and forest floor sites (n=20 pairs). My objectives were to: 1) determine the influence of substrate type on community composition and diversity, and 2) examine successional pathways and species assemblage patterns on CWD in various stages of decomposition. To meet these objectives I employed non-metric multidimensional scaling (NMDS) ordinations and unsupervised cluster analyses to identify and compare community assemblages on both substrates. These methods revealed similar species diversity and evenness between log and forest floor sites with compositional differences within and between substrates corresponding to habitat availability for colonization and light and moisture gradients. My results also suggest understory successional pathways related to decay class and characterized by an initial abundance of bryophytes, forbs, and seedlings followed by woody shrubs. Understory communities developing on logs also experienced increasing diversity, evenness, and divergence from forest floor communities consistent with log decomposition. These results differ from findings for boreal forests that reveal increasing similarity between substrate communities with increasing decay class. Recommendations for future research include the employment of a more robust sample size and direct measurements of environmental variables. Additional comparator studies are also needed to confirm the effects of forest type and decomposition on the relationship between CWD and forest understory communities. This study demonstrates how fine-scale wind disturbance fosters biodiversity through the creation of CWD substrate. My results and future research are essential for the development of silvicultural models designed to promote biodiversity in PNW coastal forests.
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Rigby, Deborah Monique. "Microbial Responses to Coarse Woody Debris in Juniperus and Pinus Woodlands." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/3515.
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The ecological significance of coarse woody debris (CWD) is usually highlighted in forests where CWD constitutes much of an ecosystem's carbon (C) source and stores. However, a unique addition of CWD is occurring in semi-deserts for which there is no ecological analog. To stem catastrophic wildfires and create firebreaks, whole Juniperus osteosperma (Torr.) and Pinus edulis (Engelm.) trees are being mechanically shredded into CWD fragments and deposited on soils previously exposed to decades of tree-induced changes that encourage "tree islands of fertility." To investigate consequences of CWD on C and nitrogen (N) cycling, we evaluated microbial metabolic activity and N transformation rates in Juniperus and Pinus surface and subsurface soils that were either shredded or left untreated. We sampled three categories of tree cover on over 40 tree cover encroachment sites. Tree cover categories (LOW = 0-15%, MID ≥ 15-45%, HIGH ≥ 45%) were used to indicate tree island development at time of treatment. In conjunction with our microbial measurements, we evaluated the frequency of three exotic grasses, and thirty-five native perennial grasses to identify links between belowground and aboveground processes. The addition of CWD increased microbial biomass by almost two-fold and increased microbial efficiency, measured as the microbial quotient, at LOW Juniperus cover. C mineralization was enhanced by CWD only in Pinus soils at the edge of tree canopies. The addition of CWD had little impact on microbial activity in subsurface soils. CWD enhanced the availability of dissolved organic C (DOC) and phosphorus (P) but tended to decrease the overall quality of labile DOC, measured as the ratio of soil microbial biomass to DOC. This suggested that the increase in DOC alone or other environmental factors novel to CWD additions lead to the increase in biomass and efficiency. P concentrations were consistently higher following CWD additions for all encroachment levels. The CWD additions decreased N mineralization and nitrification in Juniperus and Pinus soils at LOW and MID tree cover but only in surface soils, suggesting that less inorganic N was available to establishing or residual plants. The frequency of native perennial grasses, especially Elymus elymoides (Raf.), was at least 65% higher under CWD additions for all categories of tree cover, while the frequencies of exotic annual and perennial grasses were not impacted by CWD. The frequency of all perennial grasses ranged from 10-27%. Our results suggest that CWD enhanced microbial activity even when the quality of C substrates declined requiring microbes to immobilize more N. The reduction in inorganic N may promote the establishment and growth of native perennial grasses. Ultimately, the addition of CWD improved soil conditions for microbes in tree islands of fertility.
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Bambrick, Beth Marie. "Large Woody Debris Mobility Areas in a Coastal Old-Growth Forest Stream, Oregon." PDXScholar, 2013. https://pdxscholar.library.pdx.edu/open_access_etds/658.
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This study uses a spatial model to visualize LWD mobility areas in an approximate 1km reach of Cummins Creek, a fourth-order stream flowing through an old-growth Sitka spruce-western hemlock forest in the Oregon Coast Range. The model solves a LWD incipient motion equation for nine wood size combinations (0.1m, 0.4m, 1.7m diameters by 1.0m, 6.87m, 47.2m lengths) during the 2-year, 10-year, and 100-year discharge events. Model input variables were derived from a combination of field survey, remotely sensed, and modeled data collected or derived between June 2010 and July 2011. LWD mobility map results indicate the 2-year discharge mobilizes all modeled diameters, but mobile piece lengths are shorter than the bankfull channel boundary. Mobility areas for each wood size combination increases with discharge; 10-year and 100-year discharge events mobilize wood longer than average bankfull width within a confined section of the main stem channel, and mobilize LWD shorter than bankfull width within the main stem channel, side channels, and floodplain. No discharge event mobilizes the largest LWD size combination (1.7m / 47.2). Recruitment process was recorded for all LWD during June 2010, revealing that all mobile wood in the study reach was shorter than bankfull width. Based on these conflicting results, I hypothesize the distribution of wood in Cummins Creek can be described in terms of discharge frequency and magnitude, instead of as a binary mobile/stable classification. Mobility maps could be a useful tool for land managers using LWD as part of a stream restoration or conservation plan, but will require additional calibration.
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Fetherston, Kevin L. "Pattern and process in mountain river valley forests /." Thesis, Connect to this title online; UW restricted, 2005. http://hdl.handle.net/1773/5563.
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Scribner, Nick T. "Forecasting recruitment of coarse woody structure from the riparian area to the littoral zone of a north temperate lake in Wisconsin /." Link to full-text, 2006. http://epapers.uwsp.edu/thesis/2006/scribner.pdf.
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Hess, Jacquelyn Marie. "Distribution and residence times of large woody debris along South River, Shenandoah Valley, Virginia." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 184 p, 2007. http://proquest.umi.com/pqdweb?did=1400957071&sid=6&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Rogers, Megan Bryn. "Woody debris and macroinvertebrate community structure of low-order streams in Colville National Forest, Washington." Connect to this title online, 2003. http://www.dissertations.wsu.edu/Thesis/Fall2003/m%5Frogers%5F121503.pdf.
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Klinka, Karel, Gordon J. Kayahara, and Christine Chourmouzis. "Comparison of soil acidification and intensity of podzolization beneath decaying wood versus non-woody forest floors in coastal BC." Forest Sciences Department, University of British Columbia, 2001. http://hdl.handle.net/2429/763.
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Forest managers concerned with maintaining soil productivity must consider the impacts of forestry practices upon the
features of a site. One critical feature is the amount and type of organic matter on a site, which may affect soil development.
This study addresses the question of whether CWD accumulations increase the intensity of podzolization, thus reducing
the long-term productivity of a site.
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Treadwell, Simon Andrew 1968. "Patterns in community metabolism and biomass of biofilms colonising large woody debris along an Australian lowland river." Monash University, Dept. of Biological Sciences, 2002. http://arrow.monash.edu.au/hdl/1959.1/5605.
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Kayahara, Gordon J. "The effect of coarse woody debris on site productivity of some forest sites in southwestern British Columbia." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0015/NQ56570.pdf.
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Mitchell, Richard Morgan Feminella Jack W. "The influence of coarse woody debris, disturbance, and restortion on biological communities in sandy coastal plain streams." Auburn, Ala., 2009. http://hdl.handle.net/10415/2022.
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Langford, T. E. "Effects of coarse woody debris accumulation, channel structure and land use on fish populations in forested lowland streams." Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326376.
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Moreira, Andrea Bittencourt. "Estimation of volume, biomass, and carbon of coarse woody debris in native forests in São Paulo State, Brazil." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-19102017-110123/.
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The objective of this study was to test the line intersect sampling (LIS) methodology using the design-based inference with stratified systematic sampling and two transect shapes: a straight line and a cross shape, both with three different lengths (100, 150, and 200 m) to estimate the number of coarse woody debris (CWD) elements, their volume, biomass and carbon stocks; by decay class; furthermore, we fit and select CWD biomass and carbon models. The study area includes two types of native forest in the State of São Paulo, Brazil: a Seasonal Semi-deciduous Forest (SSF) and a Cerrado sensu-stricto (CSS). Two strata were chosen in each area, and in each stratum ten sampling units were installed according to a systematic sampling protocol. Each sampling unit had one North- South line of 200 m superimposed over the other lengths (100 and 150 m) and three lines (one for each length) in the East-West direction forming the cross shapes, for a total 650 m per sampling unit. All CWD elements with a diameter _ 10 cm that crossed the transect were tallied. For each element, the diameter, length, perpendicular width, decay class, and (when possible) species was recorded. Disc samples were taken from each element, from which cylinder samples were extracted then oven dried to determine density. These cylinders were milled and analyzed to determine carbon content (%). The volume of each element was calculated by taking the difference between cross-sectional area and any hollowed area, then multiplying by the element\'s length. Biomass was calculated by multiplying volume values by density values, and carbon stocks were calculated by multiplying biomass by the carbon percentage factors computed via lab analysis. Total estimators were calculated by area and per hectare for the number of CWD elements, their volume, biomass, and carbon stocks. These estimators were calculated by stratum then combined across the entire sample population. The data from each sampling unit was also used to calculate the wood density and carbon concentration by decay class, as well as to fit linear and nonlinear models. For the SSF area, the most accurate transect design was the 200 m cross shaped; and for the CSS area was selected the 150 m cross shape. Both areas showed lower biomass values (1.3 and 6.7 Mg/ha for the CSS and SSF areas, respectively) than other studies in the Amazon Forest where CWD research has been conducted. In both areas, as the decay class increased (from least to most rotten material), wood density decreased, which follows the same pattern as other literature. Carbon concentration barely changed within decay classes. Using a conversion constant of 50%, similar carbon stock results were obtained. Nonlinear models (using diameter and length as predictor variables) proved an efficient tool for predicting CWD biomass at an element level. As expected, biomass data exhibited heteroscedasticity, which was mitigated by modeling the variance of the residuals with a power function of the combined variable. Adding decay class as an indicator variable also resulted in model improvement.Este estudo buscou testar a metodologia de amostragem pela linha interceptadora (LIS), usando a inferência baseada no design, com amostragem sistemática estratificada em duas formas de transectos: linha reta e forma de cruz, ambos com três diferentes comprimentos de transectos: 100, 150 e 200 m para estimar o número de elementos, volume, biomassa e estoque de carbono de madeira morta; investigar a densidade da madeira e a concentração de carbono da madeira morta pela classe de decomposição; e, ajustar e selecionar modelos de biomassa e carbono de madeira morta, em dois tipos de floresta nativa no estado de São Paulo, Brasil: uma Floresta Estacional Semidecidual (SSF) e um Cerrado sensu-stricto (CSS). Em cada tipo florestal foram selecionados dois estratos e localidas dez unidades de amostragem em cada. A unidade de amostragem é um transecto Norte-Sul, com 200 m, que sobrepõe os outros comprimentos (100 e 150 m), e três transectos (para cada comprimento) na direção Leste-Oeste, formando a cruz, totalizando 650m. Foram medidos todos os elementos de madeira morta grossa (CWD) que cruzaram o transecto com um diâmetro _10 cm. Foi medido o diâmetro na interseção, o comprimento, a largura perpendicular, o elemento foi classificado de acordo com a classe de decomposição e, quando possível, a espécie foi identificada. De cada elemento foi retirado um disco de amostra na interseção, este foi fotografado para o cálculo da área oca. De cada disco foram extraídos cilindros, secos em estufa para determinação da densidade, estes foram moídos e analisados para determinação do teor de carbono (%). O volume de cada elemento foi calculado pela diferença da área seccional e área oca, multiplicada pelo comprimento; a biomassa foi calculada multiplicando o volume pela densidade; e o estoque de carbono foi calculado multiplicando a biomassa pela concentração de carbono. Os estimadores do total foram calculados por área e por hectare para o número de elementos de CWD, volume, biomassa e estoque de carbono; foram calculados por estrato, e combinados para a população. Os dados dos 650m de cada unidade foram utilizados para calcular as médias da densidade da madeira e concentração de carbono por classe de decomposição e, para construção de modelos lineares e não-lineares. Para a SSF, o design mais preciso foi transectos em forma de cruz, com 200 m. Para CSS foram selecionados transectos em cruz, com 150 m. As áreas apresentaram valores de biomassa 1.3-6.7 Mg/ha para CSS e SSF, respectivamente. Em ambos tipos florestais foi encontrado que à medida que a classe de decomposição aumenta (mais fresco para mais podre), a densidade da madeira diminui, seguindo os mesmos padrões encontrados na literatura. A concentração de carbono não apresentou mudança dentro das classes de decomposição. Modelos nãolineares com diâmetro e comprimento como variáveis preditoras provaram ser uma ferramenta eficiente para predizer a biomassa e carbono de CWD. Como esperado, os dados de biomassa apresentaram heterocedasticidade, mitigada pela modelagem da variância dos resíduos com uma função de potência. A adição da classe de decomposição como variável indicadora também mostrou melhora nos modelos.
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Caruso, Alexandro. "Lichen diversity on stems, slash, and stumps in managed boreal forests : impact of whole-tree harvest /." Uppsala : Swedish University of Agricultural Sciences, 2008. http://diss-epsilon.slu.se/archive/00001675/.
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Thesis (doctoral)--Swedish University of Agricultural Sciences, 2008.Includes reprints of four papers and manuscripts co-authored with others. Includes bibliographical references. Also partially available electronically via World Wide Web in PDF format; online version lacks reprints of four papers and manuscripts.
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Klinka, Karel. "The association between western hemlock fine roots and woody versus non-woody forest floor substrates in coastal British Columbia." Forest Sciences Department, University of British Columbia, 2001. http://hdl.handle.net/2429/664.
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In the wetter climates associated with the coastal forests of the Pacific Northwest, coarse woody debris (CWD) accumulations in the form of snags, downed boles, and large branches can be large in natural forest ecosystems. Although maintaining organic matter for sustainable site productivity is not in dispute, the importance of CWD as a source of soil organic matter is questionable. Forest managers attempting to optimize timber production need to know how CWD affects short-term forest tree growth and productivity. This study addresses the question of the immediate value of CWD for growth of mature (90 year old) western hemlock (Hw). Because of practical difficulty with mature trees growing in different substrates, we utilized fine root distribution or proliferation, as an indicator of important substrates.
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Nishimoto, Atsushi. "Ecology of sunken wood community in the ocean." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/188518.
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Diefenderfer, Heida Lin. "Channel morphology and restoration of Sitka spruce (Picea stichensis) tidal forested wetlands, Columbia River, U.S.A. /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/5565.
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Graham, John B. "Forest Fuel and Fire Dynamics in Mixed-oak Forests of Southeastern Ohio." Ohio University / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1132005826.
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Klinka, Karel. "Survival and growth of planted seedlings on woody and non-woody forest floor substrates in high and low light environments of coastal British Columbia." Forest Sciences Department, University of British Columbia, 2001. http://hdl.handle.net/2429/647.
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In the wetter climates associated with the coastal forests of northwestern North America, coarse woody debris (CWD) accumulations in the form of snags, downed boles, and large branches can be large in natural forest ecosystems. Seedlings often regenerate on stumps and downed logs in the understory of old-growth coastal forests. The question remains though, whether CWD is a necessary component for seedling survival and growth in forests managed for commodity production.
This study addresses one concern of forest managers: is there an immediate nutritional or moisture supply advantage conferred by CWD for the survival and growth of seedlings in the coastal climate of British Columbia? We compared survival and growth of seedlings planted in decaying wood compared to non-woody humus forms and mineral soil under
heavy shade and full light conditions. Low light environments are of particular interest since reports of the strong association between CWD and regeneration has primarily referred to understory seedlings and saplings in old-growth forests.
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Krüger, Inken [Verfasser], and Werner [Akademischer Betreuer] Borken. "Potential of above- and below-ground coarse woody debris as a carbon sink in managed and unmanaged forests / Inken Krüger. Betreuer: Werner Borken." Bayreuth : Universität Bayreuth, 2013. http://d-nb.info/1060009609/34.
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Herrmann, Steffen [Verfasser], and Jürgen [Akademischer Betreuer] Bauhus. "Decomposition dynamics and carbon sequestration of downed coarse woody debris of Fagus sylvatica, Picea abies and Pinus sylvestris = Zersetzungsdynamik und Kohlenstoffspeicherung in liegendem Totholz." Freiburg : Universität, 2017. http://d-nb.info/1137834919/34.
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Abrahamsson, Markus. "High-stumps and wood living beetles in the Swedish production forest landscape /." Alnarp : Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/2007126.pdf.
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Johansson, Therese. "The conservation of saproxylic beetles in boreal forest : importance of forest management and dead wood characteristics /." Umeå : Dept. of Animal Ecology, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/200666.pdf.
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Sass, Emma. "Lasting Legacies of Hurricane, Harvesting, and Salvage Logging Disturbance on Succession and Structural Development in an Old-Growth Tsuga canadensis-Pinus strobus Forest." ScholarWorks @ UVM, 2017. http://scholarworks.uvm.edu/graddis/817.
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Disturbance events affect forest composition and structure across a range of spatial and temporal scales, and forest development may differ after natural, anthropogenic, or compound disturbances. Following large, natural disturbances, salvage logging is a common yet controversial management practice around the globe. While the short-term impacts of salvage logging have been studied in many systems, the long-term effects remain unclear. Further, while natural disturbances create many persistent and unique microsite conditions, little is known about the long-term influence of microsites on forest development. We capitalized on over eighty years of data on stand development following the 1938 hurricane in New England to provide the longest known evaluation of salvage logging impacts, as well as to highlight developmental trajectories for eastern hemlock (Tsuga canadensis)-white pine (Pinus strobus) forests under a variety of disturbance histories. Eight decades following disturbance, there were no differences in current overstory composition between areas that were logged, hurricane disturbed, or hurricane disturbed and salvage logged, but white pine declined across most sites. In contrast, structural characteristics remain distinct between the three management histories. In the unsalvaged area, the diversity of microsites and the coverage of uprootings and pits influenced overstory tree composition, diversity, and structural characteristics. These findings underscore the long-term influence of salvage logging on forest development and the importance of natural disturbance-mediated microsite conditions on tree species growth and survival. Future salvage logging efforts should consider these impacts and provide a greater range of unsalvaged areas across the landscape to maintain these important structural legacies over the long term.
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Lindhe, Anders. "Conservation through management : cut wood as substrate for saproxylic organisms /." Uppsala : Dept. of Entomology, Swedish Univ. of Agricultural Sciences, 2004. http://epsilon.slu.se/s300.pdf.
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Rudolphi, Jörgen. "Bryophytes, lichens and dead wood in young managed boreal forests /." Uppsala : Dept. of Ecology, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/200788.pdf.
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McElhinny, Chris, and chris mcelhinny@anu edu au. "Quantifying stand structural complexity in woodland and dry Sclerophyll Forest, South-Eastern Australia." The Australian National University. Centre for Resource and Environmental Studies, 2005. http://thesis.anu.edu.au./public/adt-ANU20060322.133914.
Full textAbstract:
In this thesis I present and test a methodology for developing a stand scale index of structural complexity. If properly designed such an index can act as a summary variable for a larger set of stand structural attributes, providing a means of ranking stands in terms of their structural complexity, and by association, their biodiversity and vegetation condition. This type of index can also facilitate the use of alternative policy instruments for biodiversity conservation, such as mitigation banking, auctions and offsets, that rely on a common currency the index value that can be compared or traded between sites. My intention was to establish a clear and documentable methodology for developing a stand scale index of structural complexity, and to test this methodology using data from real stands.¶
As a starting point, I reviewed the literature concerning forest and woodland structure and found there was no clear definition of stand structural complexity, or definitive suite of structural attributes for characterising it. To address this issue, I defined stand structural complexity as a combined measure of the number of different structural attributes present in a stand, and the relative abundance of each of these attributes. This was analogous to approaches that have quantified diversity in terms of the abundance and richness of elements. It was also concluded from the review, that stand structural complexity should be viewed as a relative, rather than absolute concept, because the potential levels of different structural attributes are bound within certain limits determined by the inherent characteristics of the site in question, and the biota of the particular community will have evolved to reflect this range of variation. This implied that vegetation communities with naturally simple structures should have the potential to achieve high scores on an index of structural complexity.¶
I proposed the following five-stage methodology for developing an index of stand structural complexity:
1. Establish a comprehensive suite of stand structural attributes as a starting point for developing the index, by reviewing studies in which there is an established relationship between elements of biodiversity and structural attributes.
2. Develop a measurement system for quantifying the different attributes included in the comprehensive suite.
3. Use this measurement system to collect data from a representative set of stands across the range of vegetation condition (highly modified to unmodified) and developmental stages (regrowth to oldgrowth) occurring in the vegetation communities in which the index is intended to operate.
4. Identify a core set of structural attributes from an analysis of these data.
5. Combine the core attributes in a simple additive index, in which attributes are scored relative to their observed levels in each vegetation community.¶
Stage one of this methodology was addressed by reviewing a representative sample of the literature concerning fauna habitat relationships in temperate Australian forests and woodlands. This review identified fifty-five studies in south-east and south-west Australia, in which the presence or abundance of different fauna were significantly (p<0.05) associated with vegetation structural attributes. The majority of these studies concerned bird, arboreal mammal, and ground mammal habitat requirements, with relatively fewer studies addressing the habitat requirements of reptiles, invertebrates, bats or amphibians. Thirty four key structural attributes were identified from these fifty-five studies, by grouping similar attributes, and then representing each group with a single generic attribute. This set, in combination with structural attributes identified in the earlier review, provided the basis for developing an operational set of stand level attributes for the collection of data from study sites.¶
To address stages two and three of the methodology, data were collected from one woodland community Yellow Box-Red Gum (E. melliodora-E. Blakelyi ) and two dry sclerophyll forest communities Broadleaved Peppermint-Brittle Gum (E. dives-E. mannifera ), Scribbly Gum-Red Stringybark (E. rossii E. macrorhyncha ) in a 15,000 km2 study area in the South eastern Highlands Bioregion of Australia. A representative set of 48 sites was established within this study area, by identifying 24 strata, on the basis of the three vegetation communities, two catchments, two levels of rainfall and two levels of condition, and then locating two sites (replicates) within each stratum. At each site, three plots were systematically established, to provide an unbiased estimate of stand level means for 75 different structural attributes.¶
I applied a three-stage analysis to identify a core set of attributes from these data. The first stage a preliminary analysis indicated that the 48 study sites represented a broad range of condition, and that the two dry sclerophyll communities could be treated as a single community, which was structurally distinct from the woodland community. In the second stage of the analysis, thirteen core attributes were dentified using the criteria that a core attribute should:¶
1. Be either, evenly or approximately normally distributed amongst study sites;
2. Distinguish between woodland and dry sclerophyll communities;
3. Function as a surrogate for other attributes;
4. Be efficient to measure in the field.
The core attributes were: Vegetation cover <0.5m Vegetation cover 0.5-6.0m; Perennial species richness; Lifeform richness; Stand basal area of live trees; Quadratic mean diameter of live stems; ln(number of regenerating stems per ha+1); ln(number of hollow bearing trees per ha+1);ln(number of dead trees per ha+1);sqrt(number of live stems per ha >40cm dbh); sqrt(total log length per ha); sqrt(total largelog length per ha); Litter dry weight per ha. This analysis also demonstrated that the thirteen core attributes could be modelled as continuous variables, and that these variables were indicative of the scale at which the different attributes operated.¶
In the third and final stage of the analysis, Principal Components Analysis was used to test for redundancy amongst the core attributes. Although this analysis highlighted six groupings, within which attributes were correlated to some degree, these relationships were not considered sufficiently robust to justify reducing the number of core attributes.¶
The thirteen core attributes were combined in a simple additive index, in which, each attribute accounted for 10 points in a total index value of 130. Attributes were rescaled as a score from 0-10, using equations that modelled attribute score as a function of the raw attribute data. This maintained a high correlation (r > 0.97, p< 0.0001) between attribute scores and the original attribute data. Sensitivity analysis indicated that the index was not sensitive to attribute weightings, and on this basis attributes carried equal weight. In this form my index was straightforward to apply, and approximately normally distributed amongst study sites.¶
I demonstrated the practical application of the index in a user-friendly spreadsheet, designed to allow landowners and managers to assess the condition of their vegetation, and to identify management options. This spreadsheet calculated an index score from field data, and then used this score to rank the site relative to a set of reference sites. This added a regional context to the operation of the index, and is a potentially useful tool for identifying sites of high conservation value, or for identifying sites where management actions have maintained vegetation quality. The spreadsheet also incorporated the option of calculating an index score using a subset of attributes, and provided a measure of the uncertainty associated with this score.¶
I compared the proposed index with five prominent indices used to quantify vegetation condition or habitat value in temperate Australian ecosystems. These were: Newsome and Catlings (1979) Habitat Complexity Score, Watson et al.s (2001) Habitat Complexity Score, the Site Condition Score component of the Habitat Hectares Index of Parkes et al. (2003), the Vegetation Condition Score component of the Biodiversity Benefits Index of Oliver and Parkes (2003), and the Vegetation Condition Score component of the BioMetric Assessment Tool of Gibbons et al. (2004). I found that my index differentiated between study sites better than each of these indices. However, resource and time constraints precluded the use of a new and independent data set for this testing, so that the superior performance of my index must be interpreted cautiously.¶
As a group, the five indices I tested contained attributes describing compositional diversity, coarse woody debris, regeneration, large trees and hollow trees these were attributes that I also identified as core ones. However, unlike these indices, I quantified weeds indirectly through their effect on indigenous plant diversity, I included the contribution of non-indigenous species to vegetation cover and did not apply a discount to this contribution, I limited the direct assessment of regeneration to long-lived overstorey species, I used stand basal area as a surrogate for canopy cover, I quantified litter in terms of biomass (dry weight) rather than cover, and I included the additional attributes of quadratic mean diameter and the number of dead trees.¶
I also concluded that Parkes et al. (2003), Oliver and Parkes (2003), and Gibbons et al. (2004), misapplied the concept of benchmarking, by characterising attributes in terms of a benchmark range or average level. This ignored processes that underpin variation at the stand level, such as the increased development of some attributes at particular successional stages, and the fact that attributes can respond differently to disturbance agents. It also produced indices that were not particularly sensitive to the differences in attribute levels occurring between stands. I suggested that a more appropriate application of benchmarking would be at the overarching level of stand structural complexity, using a metric such as the index developed in this thesis. These benchmarks could reflect observed levels of structural complexity in unmodified natural stands at different successional stages, or thresholds for structural complexity at which a wide range of biota are present, and would define useful goals for guiding on-ground management.
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Klinka, Karel. "Structure and regeneration of old-growth stands in the engelmann spruce - subalpine fir zone." Forest Sciences Department, University of British Columbia, 1998. http://hdl.handle.net/2429/661.
Full textAbstract:
Old-growth stands are important for management,
conservation, wildlife, recreation, and maintaining biological
diversity in forested landscapes. However, we are lacking
the information needed to adequately identify and
characterize old-growth stands. This is especially true for
high elevation, interior forests. The characterization of stand
structure and regeneration pattern will help in the
development of site-specific guidelines for identifying old growth
stands and restoring some of the old-growth
characteristics in managed stands.
This pamphlet presents a synopsis of a study investigating
stand structure and regeneration of old-growth stands in the
Moist Cold Engelmann Spruce - Subalpine Fir (ESSFmc)
Subzone near Smithers, B.C. The three stands selected for
the study were located on zonal sites, each in different
watersheds, and the stands were established after fire. The
criteria used for selection were: i) absence of lodgepole
pine, ii) presence of advanced regeneration, and iii) abundant
snags and coarse woody debris. These stands were presumed
to represent the old-growth stage of stand development or
the final (climax) stage of secondary succession.
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Drinkard, Maureen Katherine. "IMPACTS OF A FLOOD PULSING HYDROLOGY ON PLANTS AND INVERTEBRATES IN RIPARIAN WETLANDS." Kent State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=kent1342805313.
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Veiga, Larissa Giorgeti. "Estoque de madeira morta ao longo de um gradiente altitudinal de Mata Atlântica no nordeste do estado de São Paulo." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/314895.
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Orientador: Carlos Alfredo JolyDissertação (mestrado) - Universidade Estadual de Campionas, Instituto de Biologia
Made available in DSpace on 2018-08-17T03:58:22Z (GMT). No. of bitstreams: 1 Veiga_LarissaGiorgeti_M.pdf: 2559018 bytes, checksum: 49d82fe5c9d6b0d5d80b834d2acaca19 (MD5) Previous issue date: 2010
Resumo: As florestas tropicais armazenam grandes quantidades de carbono em sua biomassa tanto acima quanto abaixo do solo. Biomassa acima do solo abrange a biomassa viva e a biomassa morta (também conhecido como necromassa). Esta e composta por madeira morta (galhos, troncos) e serapilheira. Estoque de madeira morta inclui madeira morta em pé (snag) e madeira morta caída (CWD- Coarse Woody Debris) e os estoques são resultantes do balanço entre a entrada (via mortalidade) e saída (por decomposição). Existem poucos estudos de madeira morta em florestas tropicais e estes focaram nas dicotiledoneas. No entanto, as famílias Arecaceae, Poaceae e Cyatheaceae são muito abundantes em florestas tropicais. Este estudo teve como objetivo quantificar a biomassa e estoque de carbono nos compartimentos de madeira morta (em pé e caída) ao longo de um gradiente altitudinal de Mata Atlantica do nordeste do Estado de São Paulo. Para isso, avaliamos 14 parcelas permanentes de 1 há cada estabelecidos pelo projeto BIOTA / FAPESP Gradiente Funcional em Fisionomias de Restinga 0 m (nível do mar), Floresta Ombrofila Densa (FOD) de Terras Baixas a 100 m de altitude, FOD Submontana a 400 m de altitude e FOD Montana a 1000 m de altitude. Para áreas de Floresta Submontana e Montana foram estabelecidas oito parcelas de 1 ha (quatro parcelas em cada área), na FOD Terras Baixas foram estabelecidas cinco parcelas de 1 ha e na Restinga foi estabelecida uma parcela de 1 ha. A biomassa de madeira morta apresentou tendência de aumento ao longo do gradiente. CWD foi o componente que mais contribuiu para o estoque total sendo de 46,8 (Mg/ha) para Restinga; 32,7 (Mg/ha) para FOD Terras Baixas; 44,4 (Mg/ha) para FOD Submontana e 69,5 (Mg/ha) para FOD Montana. Para "snag", os valores observados foram de 0,4 (Mg/ha); 0,6 (Mg/ha); 10,1 (Mg/ha) e 19,6 (Mg/ha) respectivamente nas áreas de Restinga, FOD Terras Baixas, FOD Submontana e FOD Montana. A contribuição da família Arecaceae foi de 9,2 Mg/ha; da família Cyatheaceae foi de 7,6 Mg/ha e de Poaceae foi de 18,4 Mg/ha. Os estoques de carbono foram 33,5 Mg/ha para FOD Montana, cerca de 21 Mg/ha para FOD Submontana e Restinga e 14,8 Mg/ha para FOD Terras Baixas. As densidades de "snag" e "CWD" diminuíram com avanço da decomposição variando de 0,3 a 0,5 (gr/cm3) para "snag" e de 0,1 a 0,4 (gr/cm3) para dicotiledôneas; de 0,3 a 0,4 (gr/cm3) para Euterpe edulis (Mart.); de 0,18 a 0,28 (gr/cm3) para Cyathea sp. e 0,09 (gr/cm3) para bambus. As famílias Arecaceae, Poaceae e Cyatheaceae, embora apresentem uma grande densidade de indivíduos vivos, contribuíram pouco para o estoque total de madeira morta. A biomassa morta respondeu, em media, por 18 % da biomassa total acima do solo, podendo ser considerada um importante reservatório de biomassa e carbono nesses ecossistemas. Como a saída de carbono deste componente e altamente dependente da umidade e da temperatura, este pode ser um compartimento particularmente sensível as mudanças previstas para o clima e, portanto, deve ser melhor avaliado em estudos futuros. Este estudo esta incluído no Projeto Biota Gradiente Funcional (FAPESP 03/12595-7).
Abstract: Tropical forests store large amounts of carbon in their biomass. Above ground biomass includes living and dead biomass (also known as necromass). Necromass is composed by dead wood (or woody debris) and litter. Woody debris stock is composed by standing dead wood (snags) and fallen dead wood (coarse woody debris) and resultants from the balance between input (via mortality) and output (via decomposition). There are few studies of dead wood in tropical forests and they have mostly focused on dicotyledons. However, Arecaceae, Poaceae Cyatheaceae families are very abundant in tropical forests. This study aimed to quantify biomass and carbon stocks in dead wood components (standing and fallen) along an elevational gradient of Atlantic rain forest of northeastern State of Sao Paulo. Therefore, we studied at 14 permanent plots of 1 ha each established by the project BIOTA / FAPESP - Functional Gradient in physiognomies of "Restinga" at 0 m (sea level), Lowland Ombrophilous Dense Forest (FOD in portuguese) at 100 m altitude, FOD Submontane at 400 m elevation and FOD Montane at 1000 m altitude. For submontane and montane forest sites were established eight (four each one) 1 ha plots, for lowland were established five 1 ha plots and for Restinga was established 1 ha plot. Dead wood biomass tended to increase along the gradient. Coarse woody debris was the component that most contributed to the total stock and represented for 46.8 (Mg / ha) for Restinga; 32.7 (Mg / ha) for FOD Lowlands, 44.4 (Mg / ha) for FOD Submontane and 69.5 (Mg / ha) for FOD Montana. For snags stocks represented for 0.4 (Mg / ha) for Restinga, 0.6 (Mg / ha) for FOD Lowlands, 10.1(Mg / ha) for FOD Submontane and 19.6 (Mg / ha) for FOD Montana. Stocks of Arecaceae was 9.2 (Mg / ha); Cyatheaceae was 7.6 Mg / ha and Poaceae was 18.4 Mg / ha. Carbon stocks were 33.5 Mg / ha for FOD Montana, around 21Mg/ha both FOD Submontane and Restinga, and 14.8 Mg / ha for FOD Lowlands. Densities of standing dead wood and fallen dead wood decreased according to advance in decomposition. For snags and for coarse woody debris the values ranged from 0.1 to 0.4 (g/cm³) for dicotyledons. For Euterpe edulis (Mart.) values ranged from 0.3 to 0.4 (g/cm3). For Cyathea sp. ranged from 0.18 to 0.28 (g/cm³) and for bamboo density was 0,09 (g/cm3). The families Arecaceae, Poaceae and Cyatheaceae, contributed little to the total stock of dead wood. The dead biomass responded, on average, by 18% of the total biomass above ground, and must be considered an important reservoir of biomass and carbon in these ecosystems. As the output of this carbon component is highly dependent on humidity and temperature, this can be a particularly sensitive compartment, anticipated changes to the climate and therefore must be better evaluated in future studies. This study is included in Biota Gradiente Funcional Project (FAPESP 03/12595-7).
Mestrado
Biologia Vegetal
Mestre em Biologia Vegetal
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Arnstadt, Tobias. "Die Rolle oxidativer Pilzenzyme für die Totholzzersetzung und die Zersetzungsdynamik von Fagus sylvatica, Picea abies und Pinus sylvestris." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-225002.
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In Waldökosystemen ist Totholz von zentraler Bedeutung, indem es zahlreichen Organismen einen Lebensraum bietet oder als Substrat dient, Bestandteil des Kohlenstoff- und Nährstoffkreislaufs ist sowie als ein wichtiges strukturelles Element fungiert. Für seine Zersetzung ist die Überwindung der Ligninbarriere von besonderer Bedeutung. Dazu sind lediglich saprobionte Pilze aus den Phyla der Basidiomycota und Ascomycota in der Lage, die verschiedene Strategien – die Fäuletypen – entwickelt haben, um Lignin abzubauen oder zu modifizieren und somit Zugang zu den vom Lignin inkrustierten Polysachariden (Zellulose und Hemizellulosen) zu erhalten. Eine besondere Rolle spielen dabei Weißfäulepilze, die mit ihren extrazellulären oxidativen Enzymen, wie Laccasen und verschiedenen Peroxidasen, Lignin komplett bis zum Kohlendioxid (CO2) mineralisieren. Trotz der Bedeutung des Ligninabbaus für die Totholzzersetzung sind extrazelluläre oxidative Enzyme im natürlichen Totholz kaum erforscht. Ziel dieser Arbeit war es, die Rolle der oxidativen Enzyme für die Totholzzersetzung unter Realbedingungen zu verifizieren, ihre räumlichen und zeitlichen Muster zu beschreiben und ihre Abhängigkeiten von verschiedenen Totholzvariablen sowie der pilzlichen Artengemeinschaft in und auf Totholz zu ermitteln. Weiter wurde die Veränderung der Totholzvariablen über den Zersetzungsprozess für unterschiedliche Baumarten vergleichend beschrieben und der Einfluss der Waldbewirtschaftung auf den Prozess untersucht. Dazu wurden 197 natürliche Totholzstämme (coarse woody debris, CWD) von Fagus sylvatica (Rotbuche), Picea abies (Gemeine Fichte) und Pinus sylvestris (Gemeine Kiefer) in unterschiedlich stark bewirtschafteten Wäldern in Deutschland untersucht. Insgesamt wurden 735 Proben genommen und darin die Aktivität von Laccase (Lacc), Genereller Peroxidase (GenP) und Mangan-Peroxidase (MnP) gemessen. Weiterhin wurden Variablen wie Dichte, Wassergehalt, pH-Wert, wasserlösliche Ligninfragmente, die Gehalte an Lignin und Extraktiven sowie an Nährstoffen und Metallen (N, Al, Ca, Cu, K, Mg, Mn und Zn) ermittelt. Die pilzliche Artengemeinschaft wurde anhand genetischer Fingerprints (F-ARISA) und mittels Fruchtkörperkartierung erfasst. In 79 % der untersuchten Totholzproben wurden oxidative Enzymaktivitäten festgestellt. Sie waren hoch variabel über den Zersetzungsverlauf sowie in Bezug auf die Probenahmepositionen innerhalb der einzelnen Stämme. Generell waren die Aktivitäten im F.-sylvatica-Totholz höher als im Koniferentotholz. Lineare und logistische Modelle zeigten, dass die pilzliche Artengemeinschaft, gefollgt von den wasserlöslichen Ligninfragmenten, die wichtigste Einflussgröße hinsichtlich der oxidativen Enzyme war. Ein saurer pH-Wert unterstützte die Funktion von Lacc und MnP; Mangan, Eisen und Kupfer waren in ausreichenden Konzentrationen vorhanden, um die Funktion und Bildung der Enzyme zu gewährleisten. Die holzabbauenden Pilze erwiesen sich als optimal an das niedrige Stickstoffangebot im Totholz angepasst, sodass ein erhöhter Stickstoffeintrag über zwei Jahre die oxidativen Enzymaktivitäten nicht weiter beeinflusste. Der pH-Wert sowie die Gehalte an Lignin, Extraktiven und Nährstoffen waren im Vergleich der drei Baumarten signifikant verschieden, obwohl die zeitlichen Veränderungen der Variablen über den Zersetzungsprozess vergleichbar waren. Die Anzahl operativer taxonomischer Einheiten (OTUs ~ molekulare Artenzahl) nahm im Verlauf der Holzzersetzung zu, während die Zahl fruktifizierender Arten für mittlere Zersetzungsgrade am höchsten war. Beide Artenzahlen nahmen zusammen mit dem Stammvolumen zu. Die Weißfäulepilze dominierten über den gesamten Zersetzungsprozess die fruchtkörperbasierte Artenzahl aller drei Baumarten, was mit dem Vorhandensein oxidativer Enzymaktivitäten einhergeht. Generell nahmen der massebezogene Gehalt des Lignins, der Extraktive und der Nährstoffe über die Zersetzung zu, während der volumenbezogene Gehalt abnahm. Der pH-Wert im Holz aller drei Baumarten sank kontinuierlich im Verlauf der Zersetzung. Eine Erhöhung der Waldbewirtschaftungsintensität hatte einen negativen Effekt auf das Stammvolumen und darüber vermittelt auf die Zahl fruktifizierender Pilzarten, jedoch kaum auf andere untersuchte Totholzvariablen. Aufgrund des häufigen Vorkommens von Weißfäulepilzen, der gleichzeitigen Präsenz oxidativer Enzymaktivitäten und des substanziellen Ligninabbaus kann auf eine fundamentale Bedeutung von Laccasen und Peroxidasen für die Zersetzung des Totholzes geschlossen werden. Nicht zuletzt die charakteristische Molekularmassenverteilung der wasserlöslichen Ligninfragmente deutete darauf hin, dass die Mn-oxidierenden Peroxidasen (MnPs) die dominierenden oxidativen Enzyme des Ligninabbaus sind. Das hoch variable Muster der oxidativen Enzymaktivitäten ist jedoch das Resultat eines komplexen Zusammenspiels der Holzeigenschaften und der pilzlichen Artengemeinschaft. Die dabei bestehenden funktionellen Abhängigkeiten müssen weiter im Detail in zukünftigen Studien analysiert und aufgeklärt werdenIn forest ecosystems, deadwood is an important component that provides habitat and substrate for numerous organisms, contributes to the carbon and nutrient cycle as well as serves as a structural element. Overcoming the lignin barrier is a key process in deadwood degradation. Only specialized saprotrophic fungi of the phyla Basidiomycota and Ascomycota developed different strategies – the rot types – to degrade lignin or to modify it in way, which allows them to get access to the polysaccharides (cellulose and hemicelluloses) that are incrusted within the lignocellulosic complex. In this context, basidiomycetous white rot fungi secreting oxidative enzymes (especially laccases and peroxidases) are of particular importance, since they are the only organisms that are able to substantially mineralize lignin to carbon dioxide (CO2). Although lignin degradation is such an important process for deadwood degradation, oxidative enzyme activities have been only poorly studied under natural conditions in deadwood. The aim of this work was to verify the importance of oxidative enzymes for deadwood degradation in the field, to describe their temporal and spatial patterns of occurrence and to identify dependencies from deadwood variables as well as from the fungal community within and on deadwood. Furthermore, the changes of different deadwood variables were studied over the whole period of degradation and compared among three tree species. Last but not least, the influence of forest management intensity on the process of deadwood degradation was evaluated. Therefor, 197 logs of naturally occurring deadwood (coarse woody debris, CWD) of Fagus sylvatica (European beech), Picea abies (Norway spruce) and Pinus sylvestris (Scots pine) were monitored and sampled in forests with different management regimes across three regions in Germany. A total of 735 samples were taken from the logs and analyzed regarding activities of laccase (Lacc), general peroxidase (GenP) and manganese peroxidase (MnP). Wood density, water content, content of lignin and extractives as well as of nutrients and metals (N, Al, Ca, Cu, K, Mg, Mn und Zn) were determined in the samples, too. The fungal community was assessed based on sporocarps (fruiting bodies) and molecular fingerprints (F-ARISA). Oxidative enzyme activities were present in 79 % of all samples. The activities were found to be highly variable both regarding the time course of degradation and their distribution within the logs. Activities were generally higher in wood samples of F. sylvatica than in samples of conifers. Linear and logistic models revealed that the fungal community structure was the most important determinant for oxidative enzyme activities in the samples, followed by the amount of water-soluble lignin fragments. Moreover, the prevalent acidic pH determined in deadwood was suitable to facilitate the function of laccase and peroxidases. Concentrations of metals (manganese, copper, iron) were sufficient to ensure synthesis and functioning of the enzymes. Deadwood-dwelling fungi turned out to be well adapted to low nitrogen concentrations and thus, an elevated nitrogen deposition over a period of two years did not affect the oxidative enzyme activities. The pH as well as the content of lignin, extractives and nutrients significantly differed among the tree species; however, their trend over the course of degradation was rather similar. Molecular species richness (determined by F-ARISA as OTUs) increased over the whole course of degradation, while the number of fruiting species was highest in the intermediate stage of degradation. Both types of species richness increased with increasing volume of the CWD logs. Over the entire degradation period, white rot fungi – based on the identification of sporocarps – were the most abundant group of wood rot fungi in and on all three tree species. This corresponds well with the overall presence of oxidative enzyme activities. During degradation, the mass-related content of lignin, extractives and nutrients frequently increased, although the volume-related content decreased. The pH of all three tree species decreased in deadwood over the whole period of degradation. Higher forest management intensity had a negative effect on the log volume of deadwood and in consequence on fungal species richness (fruiting bodies), but hardly to other analyzed variables. Based on the widespread occurrence of white rot fungi, the concomitant presence of oxidative enzyme activities as well as the substantial loss of lignin, it can be concluded that laccases and peroxidases are highly relevant for deadwood decomposition. Not least, the detected characteristic molecular size distribution of water-soluble lignin fragments points to a key role of Mn oxidizing peroxidases (MnPs) in enzymatic lignin degradation. The variable patterns of oxidative enzymes observed in wood samples is therefore the result of a complex array of wood variables and the fungal community structure, which will have to be resolved in more detail in future studies
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Chapman, Linnaea R. A. "The long-term availability of large woody debris in logged stream channels and second-growth riparian forests on the west coast of Vancouver Island." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ39179.pdf.
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Veldhuisen, Curt N. "Coarse woody debris in streams of the Drift Creek Basin, Oregon /." 1990. http://hdl.handle.net/1957/9828.
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Long, Barry A. "Recruitment and abundance of large woody debris in an Oregon coastal stream system /." 1987. http://hdl.handle.net/1957/9555.
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Barker, Jason Scot. "The effects of moisture content and initial heterotrophic colonization on the decomposition of coarse woody debris." Thesis, 2003. http://hdl.handle.net/1957/32268.
Full textAbstract:
Previous research on coarse woody debris (CWD) indicated that moisture
content and initial heterotrophic colonization of decaying wood can affect
the decomposition process. Six heterotrophic treatments were created to
simulate the effects of physical penetration of the bark and wood and the
transmission of ascomycetes versus basidiomycetes into CWD. In 1995,
360 Douglas-fir (Pseudotsuga menziesii) were randomly placed at five
replicate sites in old-growth stands. Each site had 6 heterotrophic (HET) x
2 moisture combinations (TENT). One set of logs representing the
treatment combinations was used for sampling respiration and another set
was used to measure volume affected by insect gallery excavations and
fungal rot and to determine decay rates. Respiration was sampled three
times during the summer of 2001. The results indicated that the HET
treatments were no longer affecting respiration rates. Analysis of the
average of the three sampling periods revealed no TENT effect but
examinations of the individual sampling dates suggests that tented logs
might have higher respiration rates than non-tented logs as summer
progresses. In the aggregate, the TENT treatment reduced moisture
content from 45% to 36%, a 20 percent reduction in moisture levels. The
HET and the TENT treatments did not affect decay rates. The mean
density change for the logs was -0.072 g/cm�� �� 0.03 and the mean decay
constant was 0.026 �� 0.011. The TENT treatment did affect heterotrophic
activity. The mean volume of wood borer excavation and extent of brown
rot was higher in the tented logs (256 cm��) than in the non-tented logs
(59.9 cm��). There was also a statistically significant interaction between
the HET and TENT treatments. The largest differences in volume affected
by wood borers and fungal rot were found in treatments that injected
ascomycetes into the experimental logs. In sum, there was limited
evidence that the differences in moisture content caused by the TENT
treatment affected the decomposition process but the HET treatments
appear to not be directly influencing decomposition after six years. The
findings suggest differences in the initial community composition of
heterotrophs have a decreasing impact on the decomposition process as it
progresses.Graduation date: 2004
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Bustos-Letelier, Oscar. "Wind direction and effect of tree lean on coarse woody debris production /." 1994. http://hdl.handle.net/1957/9395.
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Hopkins, AJM. "The taxonomy and ecology of wood decay fungi in Eucalyptus obliqua trees and logs in the wet sclerophyll forests of southern Tasmania." Thesis, 2007. https://eprints.utas.edu.au/7959/1/02_wholeThesis.pdf.
Full textAbstract:
The wet sclerophyll forests in southern Tasmania are dominated by Eucalyptus obliqua and are managed on a notional silvicultural rotation length of 80 to 100 years. Over time, this will lead to a simplified stand structure with a truncated forest age and thus reduce the proportion of coarse woody debris (CWD), such as old living trees and large diameter logs, within the production forest landscape. Course woody debris is regarded as a critical habitat for biodiversity management in forest ecosystems. Fungi, as one of the most important wood decay agents, are key to understanding and managing biodiversity associated with decaying wood. In Australia, wood-inhabiting fungi are poorly known and the biodiversity associated with CWD has not been well studied.
This thesis describes two studies that were undertaken to examine the importance of CWD as habitat for wood-inhabiting fungi in the wet sclerophyll forests of Tasmania.
Study one examined the effect of changing tree age on the fungal species richness, fungal community composition and rotten wood associations within the tree. Six living E. obliqua trees in each of three age-classes (69, 105 and >150 years old) were felled. Each tree was cross-cut at nine standard sampling points and the decay profile was mapped. Fungi were isolated from rotten wood at each sampling point, and from control samples of clear heartwood and sapwood. Samples of each rotten wood type were collected and classified, based on their colour and texture.
Wood-inhabiting fungi in Australia are not well known, making the identification of fungal cultures problematic. In study one, cultures of wood-inhabiting fungi were grouped into putative species groups and identified using both morphological techniques and polymerase chain reaction (PCR) and sequencing of the internal transcribed spacer (ITS) region of the ribosomal DNA.
Ninety-one species of wood-inhabiting fungi were isolated from the 18 trees examined in study one. Eight different rotten wood types were identified and studied. The community composition of wood-inhabiting fungi in trees greater than 150 years old (the oldest age-class examined) was very different compared with those found in the younger two age-classes; more than half of all species were only found in these older trees. In addition, trees in the oldest age-class contained greater volumes and proportions of rotten wood habitat.
The second study examined the wood-inhabiting fungi that had been isolated in a previous study by Z-Q Yuan (University of Tasmania) from large (>85 cm) and small (30-60 cm) diameter E. obliqua logs in mature, unlogged forests and 20-30 year-old logged forests that were regenerating after clearfelling. The previously described morphospecies were tested using PCR-sequencing of the ITS region of ribosomal DNA and a consensus final species groupings was obtained.
This study determined that a total of 60 species of wood-decay fungi had been commonly isolated from the 36 logs examined. Significant differences in fungal community structure were found between mature forests and regenerating forests. Some differences in fungal species richness and community composition were also found between logs of different sizes.
These studies are among the first to examine wood-inhabiting fungi in mature E. obliqua trees and logs in Tasmania. The ecological information obtained from this research will assist in the development and deployment of strategies for the management of mature living trees and logs in wet eucalypt forests in Tasmania. This research suggests there is a need for forest managers to consider instigating measures that allow for some trees in the production forest landscape to live long enough to develop decayed wood habitat. This will provide important habitat for fungi as both trees and large diameter logs, sustaining an important component of forest biodiversity.
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Heiman, David C. "Recruitment trends and physical characteristics of course woody debris in Oregon Coast Range streams /." 1988. http://hdl.handle.net/1957/9801.
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