Biogeochemical Baselines of Unpolluted Old-Growth Forests
Collaborators:	Alison Cross (OSU)
Funding:	USGS-FRESC, CFER

Biogeochemical cycles of essential nutrients exert strong control over the development of forest ecosystems. Human activities can however dramatically alter these cycles away from natural baseline conditions, often with poorly understood consequences for long-term ecosystem sustainability. In the Oregon Coast Range, clear-cut logging has converted large areas of late-successional forests to young stands dominated by Douglas-fir. The consequences of these changes remain difficult to evaluate due to a lack of baseline information on how biogeochemical cycles work in old-growth reference forests of this region.

This study seeks to characterize landscape-level patterns of nutrient concentrations in plants and soils of forests in the Oregon Coast Range, with a particular focus on unmanaged old-growth forest remnants. We are evaluating impacts of landscape-level variations in nitrogen (N) biogeochemistry, soil parent material, and tree species-specific effects on nutrient availability through spatially extensive sampling.

The results emerging from this work will provide essential baseline information on natural variations in biogeochemical cycles across the region, which can serve as reference points for understanding how natural and anthropogenic disturbances influence nutrient availability. At national and global scales, this work will contribute substantially to our understanding of how biogeochemical cycles work in unpolluted, old-growth temperate forests. These studies will also test and refine ecosystem biogeochemical theory, which has been developed primarily from studies of more polluted and/or disturbed forests.

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