PARENT SESSION
Poster Session # 14: Forest Ecology.
Wednesday, August 6 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
Woody detritus in a shifting agricultural ecosystem.
Eaton, James*,1, Lawrence, Deborah1, 1 University of Virginia, Charlottesville, VA
ABSTRACT- Woody detritus is an often overlooked, but potentially significant, carbon source in older secondary forests and an important sink in younger secondary forests. The southern Yucatan peninsular region (SYPR) is characterized by a mosaic of agricultural lands and secondary forests. Shifting cultivation, in the form of slash and burn agriculture, degrades this dry tropical forest, yet leaves much woody detritus due to incomplete burns. These inputs are important in an early successional ecosystem because woody detritus rebuilds soils, restores soil nutrients, and limits erosion. We explored the major environmental constraints on the transition from sink to source, by sampling along a chronosequence of sites and a regional precipitation gradient. To determine the heterogeneity, structure, and dynamics of woody detritus during succession, we inventoried woody detritus stocks at two locations in the southern Yucatan peninsular region, while monitoring inputs and decomposition of woody detritus over a two year period at one of these locations. Stocks of coarse (≥10 cm diameter) woody debris were inventoried in two 16 m fixed radius plots, while a sub-sample of these plots using 1m2 quadrats yielded estimates of fine (≥1.8 cm to ≤ 10 cm diameter) woody debris for each site. Every 6 months, we measured inputs of coarse woody debris (CWD) to these plots. Allometric equations, based on diameter at breast height of living trees, were used to estimate inputs of fine woody debris (FWD). The decomposition rates for the 4 most common secondary forest species are being monitored for 2 size classes over a two year period. Examining the impact of land-use and land-use change on the heterogeneity, structure, and dynamics of woody detritus in an ecosystem will allow us to understand the function of woody detritus in secondary forests.
Key words: carbon, secondary forest, woody detritus, dry tropical forest