The proposed research will examine changes in nitrous oxide emissions from two forest ecosystems in response to chronic additions of ammonium nitrate. Measurements will also be made of nitrogen mineralization and nitrification, nitrate leaching, and changes in the biomass and chemical content of foligage and fine roots. The purpose of this combination of measurements is to increase our understanding of the relationships between elevated rates of nitrogen inputs currently occurring in many temperate forest zones, the rate and form of nitrogen cycling in those forests, and the impact of increasing nitrogen cycling rates on regional emissions of nitrous oxide. An additional goal is to develop quantitative relationships between emissions and foliar biomass and chemistry which can be used in conjunction with emerging remote sensing technologies to estimate Nz0 flux over whole vegetation types or regions.
