P.J., M. J. Mitchell and F.P. Bowles. 1998. Soil warming in a northern
hardwood forest: trace gas fluxes and leaf litter decomposition.
Canadian Journal Forest Research, 28(9):1365-1372.
The response of trace gas fluxes (CO2, CH4, and N2O)
and litter decomposition to increased soil temperature was evaluated in
a northern forest. Four experimental plots (10 x 10 m) had heating
cables installed within the forest floor. Temperature at 5 cm were
increased 2.5, 5.0 or 7.5oC in individual plots during the field
season in 1993 and 1994. The fourth plot was a cabled, nonheated
reference. Trace gas fluxes were monitored using closed chambers.
Soil moisture was monitored using tensiometers and time domain reflectometry.
Changes in leaf litter decomposition were quantified using litter bags
for American beech (Fagus grandifolia Ehrh.) and sugar maple (Acer
saccharum Marsh.) litter. Fluxes of CO2
increased exponentially with increased soil temperatures within treatments
and were higher in heated plots than in the reference plot. Temperature
coefficients (Q10) and mass remaining of American beech
leaf litter decreased with the level of heating, suggesting a nonlinear
microbial response to elevated temperatures. Soil water content exhibited
the most influence on CH4 and N2O flux in the second
season. The experimental manipulations showed the importance of evaluating
the influence of soil temperature coupled with effects of N and moisture