Effects of clear-cutting on decomposition rates of litter and forest floor in forests of British Columbia

The rate of mass loss of three standard substrates (pine needle litter, aspen leaf litter, and forest floor material) was measured in forests and adjacent clearcuts at 21 sites throughout British Columbia, to test the hypotheses that (i) rates of mass loss are greater in clearcuts than in forests and (ii) clear-cutting would stimulate decomposition most in colder zones. Mass loss ranged from 53 to 75% after four years in pine needles, 49 to 70% after 3 years in aspen leaves, and 11 to 20% after 4 years in forest floor material. Mass loss from pine needles was significantly slower in clearcuts throughout the 4-year incubation. Aspen leaf litter and forest floor material lost mass at similar rates in forests and clearcuts. The effect of clear-cutting did not vary between relatively cold and warm sites. The effect of clear-cutting was not related to the size of the clearcuts, which ranged from 1 to 97 ha.