Nocturnal ecosystem respiration rates derived from nocturnal measurements of net ecosystem exchange of CO2 (NEE), were made in a Deciduous forest at Petersham, Massachusetts (42.54° N, 72.18° W; 340 m above m.s.l.) from January through September, 1994, using the eddy correlation technique. The objective of this study was to evaluate the dependence of nocturnal ecosystem respiration rate on soil and air temperature.
Daily and seasonal patterns analysis of NEE, ecosystem respiration rate, air temperature above canopy and soil temperature at 0.05 m, 0.20 m and 0.50 m depths, were based on hourly measurements over a 111-day period. Maximum NEE of CO2, occurred around noon and ranged from - 21 µmol/m2.s in June, which is the peak of growing season to 4.5 µmol/m2.s in September, during leaf senescence. The relationship between ecosystem respiration rate and temperature data showed that air temperature above canopy and soil temperature at 0.05 m depth, accounted for about 77 % and 67 %, respectively, of the variance in ecosystem respiration rate.