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Deborah Lawrence - One of the best experts on this subject based on the ideXlab platform.
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Woody Debris stocks and fluxes during succession in a dry tropical forest
Forest Ecology and Management, 2006Co-Authors: James M. Eaton, Deborah LawrenceAbstract:Abstract In Southern Mexico, shifting cultivation is creating a mosaic of agricultural lands, secondary forests, and disturbed mature forests (montanas). Increased land-use change, due to population and market pressures has changed the structure and function of these forests. This study investigates the stocks and fluxes of Woody Debris during the course of secondary succession. We inventoried fine (≥1.8 cm to ≤10 cm diameter) and coarse Woody Debris (≥10 cm diameter) stocks in 28 stands. In a subset of montanas and secondary forest fallows, we monitored inputs and decomposition over a 2-year period. Total Woody Debris stocks were largest in montanas (37.46 Mg/ha) and in the first year after clearing (milpa, 51.62 Mg/ha). Woody Debris was 22% of the total aboveground biomass in montanas and 88% in milpas. Although stocks were highly variable in secondary forest, coarse Woody Debris stocks were roughly three times larger than fine Woody Debris stocks. Coarse Woody Debris stocks decreased following cultivation for 10–15 years, until inputs exceeded losses to decomposition. Inputs were higher in montana (0.91 Mg ha −1 year −1 ) than in secondary forest (0.11 Mg ha −1 year −1 ). Coarse Woody Debris inputs were higher during the dry season, while fine Woody Debris inputs tended to be higher during the wet season. Decomposition varied significantly among tree species, with decomposition rate constants from 0.124 to 0.643 year −1 for coarse Woody Debris and 0.368–0.857 year −1 for fine Woody Debris. In young forests, when Woody Debris stocks are largest, cultivation history is the most important factor in predicting stocks of Woody Debris. As forest age increases Woody Debris processes, both inputs and decomposition, become increasingly important factors in regulating Woody Debris stocks, and therefore age is a better predictor of Woody Debris stocks in older forests.
Kurt D. Fauseh - One of the best experts on this subject based on the ideXlab platform.
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Characteristics and function of large Woody Debris in subalpine Rocky Mountain streams in northern Colorado
Canadian Journal of Fisheries and Aquatic Sciences, 1995Co-Authors: Ann D. Richmond, Kurt D. FausehAbstract:Large Woody Debris has been well studied in coastal forests of the Pacific Northwest, but little is known of its role in Rocky Mountain streams. Large Woody Debris was measured in 11 undisturbed streams draining subalpine old-growth forests in north central Colorado to assess abundance, characteristics, and function. Although large Woody Debris in Colorado had smaller diameter, length, and volume than in the Pacific Northwest, its abundance and function were similar. The majority of pools (76%) were plunge and dammed pools formed by large Woody Debris, most of which spanned the channels perpendicular to stream flow. Smaller streams had a greater proportion of such perpendicular pool-forming pieces than larger streams. Four disturbed streams had significantly less and smaller large Woody Debris than undisturbed streams. Flows in larger undisturbed streams were capable of moving large Woody Debris, so pieces were more often located at the stream margins, oriented diagonally, or distributed in clumps than in...
James M. Eaton - One of the best experts on this subject based on the ideXlab platform.
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Woody Debris stocks and fluxes during succession in a dry tropical forest
Forest Ecology and Management, 2006Co-Authors: James M. Eaton, Deborah LawrenceAbstract:Abstract In Southern Mexico, shifting cultivation is creating a mosaic of agricultural lands, secondary forests, and disturbed mature forests (montanas). Increased land-use change, due to population and market pressures has changed the structure and function of these forests. This study investigates the stocks and fluxes of Woody Debris during the course of secondary succession. We inventoried fine (≥1.8 cm to ≤10 cm diameter) and coarse Woody Debris (≥10 cm diameter) stocks in 28 stands. In a subset of montanas and secondary forest fallows, we monitored inputs and decomposition over a 2-year period. Total Woody Debris stocks were largest in montanas (37.46 Mg/ha) and in the first year after clearing (milpa, 51.62 Mg/ha). Woody Debris was 22% of the total aboveground biomass in montanas and 88% in milpas. Although stocks were highly variable in secondary forest, coarse Woody Debris stocks were roughly three times larger than fine Woody Debris stocks. Coarse Woody Debris stocks decreased following cultivation for 10–15 years, until inputs exceeded losses to decomposition. Inputs were higher in montana (0.91 Mg ha −1 year −1 ) than in secondary forest (0.11 Mg ha −1 year −1 ). Coarse Woody Debris inputs were higher during the dry season, while fine Woody Debris inputs tended to be higher during the wet season. Decomposition varied significantly among tree species, with decomposition rate constants from 0.124 to 0.643 year −1 for coarse Woody Debris and 0.368–0.857 year −1 for fine Woody Debris. In young forests, when Woody Debris stocks are largest, cultivation history is the most important factor in predicting stocks of Woody Debris. As forest age increases Woody Debris processes, both inputs and decomposition, become increasingly important factors in regulating Woody Debris stocks, and therefore age is a better predictor of Woody Debris stocks in older forests.
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Woody Debris and the Carbon Budget of Secondary Forests in the Southern Yucatán Peninsular Region
2005Co-Authors: James M. EatonAbstract:Land-use change, in the Southern Yucatan Peninsular Region (SYPR), is creating a mosaic of agricultural lands, secondary forests, and disturbed mature forests (montanas). Swidden agriculture, in the form of slash and burn shifting cultivation, is the major cause of land-use change and is degrading this dry tropical forest. Increased rates of land-use change, due to population pressures, in the SYPR are thought to have changed the structure and function of these forests. This study investigates the stocks and fluxes of Woody Debris during the course of secondary succession. This study also quantifies the carbon stocks of secondary forests and montanas along a regional precipitation gradient. On average, Woody Debris represents 88% of the total aboveground biomass stock during cultivation and 22% in montanas. Woody Debris is important in early successional ecosystems because Woody Debris rebuilds soils, restores soil nutrients, and limits erosion. I have inventoried Woody Debris stocks, and monitored inputs and decomposition over a two year period in the SYPR. Woody Debris stocks are largest immediately following cultivation and in montanas. Stocks of Woody Debris decrease significantly (p=0.002) as the number of prior cultivation cycles increase. Although stocks of fine (≥1.8 cm to ≤ 10 cm diameter) and coarse Woody Debris (≥10 cm diameter) are highly variable in secondary forest, coarse Woody Debris stocks are roughly three times larger than fine Woody Debris stocks. Coarse Woody Debris stocks decrease following cultivation for 10-15 years, until inputs exceed decomposition. Inputs of coarse Woody Debris are highest during the dry season, while fine Woody Debris inputs are highest during the wet iii season. The annual input rate to montana (0.9 Mg ha yr) is the same for coarse and fine Woody Debris. Decomposition was significantly dependent on tree species (p=0.001) and time since placement (p=0.001). Decomposition rate constants varied from 0.1240.643 yr for coarse Woody Debris and 0.368-0.857 yr for fine Woody Debris. In situ measurements of carbon stocks, at fine spatial scales, were used to determine how the conversion of dry tropical forest to agricultural land alters the size and distribution of carbon stocks in the SYPR. Live aboveground biomass, coarse Woody Debris, fine Woody Debris, forest floor litter, and soil were sampled in 64 sites at three locations along a precipitation gradient in Campeche and Quintana Roo, Mexico. Live aboveground biomass was calculated from stem and height measurements in 500 m plots using published allometric equations. Root biomass was estimated from live aboveground biomass. Stocks of coarse Woody Debris were inventoried in two 16-m radius plots at 28 sites. Fine Woody Debris was sub-sampled in each of these plots in eight 1-m quadrats. Forest floor litter was collected from four 1-m quadrats in 36 sites. Soil samples from 015 cm, 45-50 cm and 95-100 cm yielded estimates of soil carbon stocks. Carbon stocks in all forest components were significantly affected by the age class of the forest (p
Druscilla S. Sullivan - One of the best experts on this subject based on the ideXlab platform.
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Maintenance of small mammals using post-harvest Woody Debris structures on clearcuts: linear configuration of piles is comparable to windrows
Mammal Research, 2018Co-Authors: Thomas P. Sullivan, Druscilla S. SullivanAbstract:Management of post-harvest Woody Debris structures (e.g., piles and windrows) may help conserve mammal diversity in commercial forest landscapes. A windrow (continuous Woody Debris) provides a linear habitat to connect patches and reserves of uncut forest and riparian areas to maintain forest-floor small mammals and allow some of their avian and mammalian predators to access and traverse clearcut openings. However, most post-harvest residues are arranged in independent piles of Woody Debris (separated by 20–30 m, on average) and we asked if a linear configuration of piles would provide similar habitat conditions for small mammals as that achieved by a windrow of continuous Woody Debris. We tested two hypotheses (H) that piles of Woody Debris arranged in a linear configuration, on newly clearcut sites, would (H_1) enhance (a) abundance of the major small mammal species ( Myodes gapperi and Microtus spp.), and (b) total abundance, species richness, and species diversity of the forest-floor small mammal community; compared with dispersed (conventional) treatment of Woody Debris. H_2 predicted that, because of the continuity of habitat, responses of small mammals in windrows would be greater than those in piles of Woody Debris. Three study areas were monitored in southern British Columbia, Canada, and each had three treatments of Woody Debris: dispersed, in a linear set of piles, and as a windrow. Forest-floor small mammals were sampled by live-trapping in spring and fall periods from 2010 to 2012. Woody Debris in a linear configuration of piles and in windrows enhanced mean abundance of the southern red-backed vole ( M. gapperi ), total voles, and total abundance of small mammals compared with the dispersed treatment. Small mammal responses were variable between spring and fall periods, but overall mean values ± 95% CIs indicated that abundance of M. gapperi , total voles, and total small mammals were reasonably similar in piles and windrows.
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Bioenergy or biodiversity? Woody Debris structures and maintenance of red-backed voles on clearcuts
Biomass and Bioenergy, 2011Co-Authors: Thomas P. Sullivan, Druscilla S. Sullivan, Pontus M.f. Lindgren, Douglas B. Ransome, Justin G. Bull, Catalin RisteaAbstract:Abstract Wood residues from forest harvesting or disturbance wood from wildfire and insect outbreaks may be viewed as biomass “feedstocks” for bioenergy production, to help reduce our dependence on fossil fuels. Biomass removals of Woody Debris may have potential impacts on forest biodiversity and ecosystem function. Forest-floor small mammals, such as the southern red-backed vole (Myodes gapperi) that typically disappear after clearcut harvesting, may serve as ecological indicators of significant change in forest structure and function. We tested the hypothesis that large piles and windrows of Woody Debris would enhance the population dynamics (abundance, reproduction, and survival) of M. gapperi, compared with a dispersed treatment on clearcut sites. We also investigated the trade-offs in values and functions between the apparently competing uses of bioenergy or biodiversity. Red-backed voles were intensively live-trapped from 2007 to 2009 in replicated Woody Debris treatments of dispersed, piles, windrows, and uncut mature forest at each of two study areas in south-central British Columbia, Canada. Our hypothesis was supported, at least on sites with substantial Woody Debris structures. Here we show, for the first time, that constructed piles and windrows of Woody Debris maintain habitat for red-backed voles, and presumably some components of biodiversity, on clearcuts. Woody Debris from harvested sites can be used for bioenergy production, but this depends on the interplay between volume, transportation distance, plant capacity, and electricity price. These variables define the economic value of Woody Debris and we feel this is an indirect expression of the value of biodiversity. The response of policy makers will reflect how we prioritize the challenge of managing biodiversity as we develop new sources of renewable energy.
Faming Wang - One of the best experts on this subject based on the ideXlab platform.
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Nutrient limitation of Woody Debris decomposition in a tropical forest: contrasting effects of N and P addition
Functional Ecology, 2015Co-Authors: Yao Chen, Emma J. Sayer, Yongzhen Ding, Jun Wang, Jianwu Tang, Faming WangAbstract:Summary Tropical forests represent a major terrestrial store of carbon (C), a large proportion of which is contained in the soil and decaying organic matter. Woody Debris plays a key role in forest C dynamics because it contains a sizeable proportion of total forest C. Understanding the factors controlling the decomposition of organic matter in general, and Woody Debris in particular, is hence critical to assessing changes in tropical C storage. We conducted a factorial fertilization experiment in a tropical forest in South China to investigate the influence of nitrogen (N) and phosphorus (P) availability on Woody Debris decomposition using branch segments (5 cm diameter) of four species (Acacia auriculaeformis, Aphanamixis polystachya, Schefflera octophylla, and Carallia brachiata) in plots fertilized with +N, +P, or +NP, and controls. Fertilization with +P and +NP increased decomposition rates by 5–53%, and the magnitude was species specific. Contrary to expectations, we observed no negative effect of +N addition on decay rates or mass loss of Woody Debris in any of the four study species. Decomposition rates of Woody Debris were higher in species with lower C : P ratios regardless of treatment. We observed significant accumulation of P in the Woody Debris of all species in plots fertilized with +P and +NP during the early stages of decomposition. N release from Woody Debris of Acacia (N-fixing) was greater in the +P plots towards the end of the study, whereas fertilization with +N had no impact on the patterns of nutrient release during decomposition. Synthesis: Our results indicate that decomposition of Woody Debris is primarily constrained by P availability in this tropical forest. However, contrary to expectations, +N addition did not exacerbate P limitation. It is conceivable that decay rates of Woody Debris in tropical forests can be predicted by C : P or lignin : P ratios, but additional work with more tree species is needed to determine whether the patterns we observed are more generally applicable.
