The purpose of the research is to assess the regional impact of chronic nitrogen additions to spruce-fir forests in the northeastern U.S. on net nitrous oxide (N2O) and methane (CH4) fluxes. The approaches to be used include intensive sampling of gas fluxes in a series of previously studied spruce-fir forests covering the region between eastern Maine and eastern New York, and from an experimental site in Southern Vermont where chronic N additions are being made to a red spruce stand. Both remote sensing and Geographic Information System (GIS) methods will be used to extrapolate measurements to regional totals, and an evaluation will be made of the effectiveness of these two approaches. Specific activities include: 1) intensive measurements of net N2O and CH4 flues between the atmosphere and soils in five areas within the spruce-fir forest type with documented differences in nitrogen economies, 2) collection of foliar samples from each site for determination of total canopy lignin, nitrogen and cellulose content, 3) remote sensing of canopy chemistry using broad-band (TM) and high spectral resolution (FLI, AVIRIS) sensors, and 4) the use of both remote sensing data, and extensive ground surveys of nitrification rates extrapolated through the use of a geographic information system, to estimate of net N2O and CH4 fluxes for the spruce-fir zone. The project is jointly funded by NSF and NASA. The investigators are well qualified for this type of research and the facilities and institutional support for the project are excellent.
