Recent field studies have made it possible to incorporate more broadly-derived relationshipes into decomposition models and to test them more broadly as well . At the landscape scale, the forest floor exhibits high levels of heterogeneity in structure and function. In this study we used field observations of changes in proximate C fractions and N content in litter over time, together with field observations of leaching fluxes of dissolved organic C and N, to construct DocMod, a model of C fraction and N dynamics during litter decomposition and humification. Leaching of dissolved organic matter from the forest floor is included explicitly. We linked this to the terrestrial ecosystem model PnET, coupled the two process models together in a GIS and modeled landscape-scale patterns in forest-floor mass and N dynamics in the White Mountain National Forest in New Hampshire, USA. This area has strong elevational gradients in climate and forest type. Our blind predictions of decomposition rates in four widely different ecosystems validated well against field measurements. The model also reproduced patterns in published chronosequence measurements of forest floor mass following clear-cutting in the White Mountains.
GIS images of litter production, forest-floor mass, and leaching of dissolvedorganic C and N across the White Mountain National Forest are available.Images are in Idrisi format at 10 ha resolution.