HR: 0800h
AN: H31F-0720    [Abstracts]
TI: Associations between regional moisture gradient, tree species dominance, and downed wood abundance
AU: * Johnson, A C
EM: ajohnson03@fs.fed.us
AF: USDA, Forest Service, Pacific Northwest Research Station, 620 SW Main, Suite 400, Portland, OR 97205, United States
AU: * Johnson, A C
EM: ajohnson03@fs.fed.us
AF: Portland State University, Environmental Sciences and Resources, PO Box 751, Portland, OR 97207, United States
AU: Mills, J
EM: jmills@fs.fed.us
AF: USDA, Forest Service, Pacific Northwest Research Station, 620 SW Main, Suite 400, Portland, OR 97205, United States
AB: Downed wood functions as a source of nurse logs, physical structure in streams, food, and carbon. Because downed wood is important in upland and aquatic habitats, an understanding of wood recruitment along a continuum from wet to dry landscapes is critical for both preservation of biodiversity and restoration of natural ecosystem structure and function. We assessed downed wood in public and private forests of Washington and Oregon by using a subset of the Forest Inventory and Analysis (FIA) database including 15,842 sampled conditions. Multivariate regression trees, ANOVA, and t-tests were used to discern environmental conditions most closely associated with abundance of woody debris. Of the 16 parameters included in the analysis, rainfall, forest ownership, number of damaged standing trees, and forest elevation were most indicative of woody debris abundance. The Hemlock/spruce Group, including hemlock, spruce, cedar, and white pine, most associated with wetter soils, had significantly more downed wood than 12 other forest groups. The Ponderosa Pine Group, indicative of drier sites with higher fire frequencies, included ponderosa pine, sugar pine, and incense cedar, and had significantly less downed wood volume. Overall, the amount of woody debris in either the Spruce/hemlock Group or the Ponderosa Pine Group did not change significantly as tree age increased from 5 to 350 years. Plots within the Hemlock/spruce with greater standing tree volume also had significantly greater downed wood volume. In contrast, greater downed wood volume was not associated with greater standing tree volume in the Ponderosa Pine Group. Knowledge of linkages among environmental variables and stand characteristics are useful in development of regional forest models aimed at understanding the effects of climate change and disturbance on forest succession.
DE: 1813 Eco-hydrology
DE: 1847 Modeling
DE: 1851 Plant ecology (0476)
DE: 1854 Precipitation (3354)
SC: Hydrology [H]
MN: 2007 Fall Meeting