My research program strives to increase our understanding of the processes of carbon (C) and nitrogen (N) cycling in terrestrial ecosystems, and how human-induced disturbances influence these processes. Perturbation of these cycles has enormous consequences to humans. Changes in the C cycle, particularly those that release C to the atmosphere, will contribute to rising levels of carbon dioxide in the atmosphere and rates of climatic change. Nitrogen deposition may enhance forest growth rates, but excess N can lead to reduced soil and water quality and increased emissions of greenhouse gases such as N2O. The key questions I am addressing at present include 1) how do forest management practices and other disturbances, particularly non-stand-replacing events, alter rates of C exchange with the atmosphere 2) how will soil disturbance and climate-related shifts in plant community distribution in the high Arctic influence soil biogeochemical processes 3) what is the fate of different forms of N added to forest ecosystems, and how does this exogenous N influence rates of C exchange between the forest and the atmosphere, and 4) is biomass production for bioenergy sustainable, and how does it impact the climate system (both through GHG production and changes in surface reflectance). I am also interested in the impact of invasive plant species on plant/soil interactions, and the impact of historical land-use patterns on contemporary C and N cycling processes. My research approach includes field studies, development and testing of process-based terrestrial C and N cycling models, and use of remote sensing and GIS to extrapolate research results in space and time. When possible, I try to use my research results to help address key environmental policy issues.
