McHale, Patrick, J. 1996. Carbon dioxide, methane and nitrous oxide dynamics in a northern hardwood forest under experimental manipulation of soil temperature. M.S. Thesis, State University of New York, College of Environmental Science and Forestry, Syracuse, 106 pp.

Abstract: Heating cables were buried (5 cm depth) in four 10 x 10 m forested plots. Three plots (2.5, 5.0 and 7.5C above reference) were heated from May through September during 1993 and 1994. Trace gas fluxes (CO2, CH4 and N2O) were quantified using closed chambers and from concentrations in soil air samples (1994 only). Soil temperature, soil moisture and daily precipitation data were also monitored.

The reference plot had average fluxes (using closed chambers) of 71 and 74 mg CO2-Cm-2h-1 for CO2, 60 and 52 for CH4 g CH4-Cm-2h-1, and 0.8 and 4.1 g N2O-N m-2h-1, in 1003 and 1994, respectively. Carbon dioxide and N2O efflux (1994 only) and CH4 uptake (both years) were negatively correlated with increasing soil moisture. Soil temperature was positively correlated with CO2 efflux and CH4 uptake in both years, and with N2O in 1994. The rate of response (Q10) of CO2 efflux and CH4 uptake to soil temperature was reduced with increased levels of heat treatment, suggesting that labile C may have been depleted in heated plots. These results suggest that higher loss rates of CO2 during climate change may be short-term, and also, global warming may lead to lower rates of CH4 uptake in northern aerobic soils.