GIS and biogeochemical models for examining the legacy of forest disturbance in the Adirondack Park, NY, USA

Human dominance over the spatial patterns of nitrogen (N) cycling in forested ecosystems of the northeast United States is regulated through the locally variable legacy of historic forest disturbance, and the regionally variable effects of chronic atmospheric N deposition. In order to effectively use ecosystem models to understand the combined influence of these perturbations, the level of detail, or resolution, of input data must be carefully matched to the scale of analysis. By interpreting historic accounts of anthropogenic forest disturbances in the Adirondack Park between 1860 and 1916 into GIS models, we developed two realistic disturbance history scenarios of differing resolution. Using these models, we found predictions of present-day N cycling obtained from an ecosystem process model, PnET-CN, to be sensitive to the resolution of century-old disturbance input data. PnET-CN predictions obtained using the higher-resolution (more complex) disturbance scenario produced significantly different predictions of N cycling for selective-cut versus clear-cut disturbance regimes. Our experience with the combined use of GIS and a biogeochemical model suggests that the development of spatially explicit disturbance history information from historic accounts may enable future research to: (1) develop more precise quantitative disturbance history inputs at appropriate resolutions for ecosystem process models, and (2) more adequately characterize field-testable differences in old-growth, selective-cut, and clear-cut disturbance regimes.