PARENT SESSION
Poster Session 2: Forest Ecology
Monday, August 8, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Shifts in litterfall and decomposition under intensive silviculture regimes in pine (Pinus strobus L.) plantations.
Munson, Alison*,1, Coyea, Marie1, Parsons, William1, 1 Université Laval, Quebec, QC, Canada
ABSTRACT- Intensive forest management is gaining ground in Canada under scenarios of uncertain wood supply in several provinces. A study of tree and ecosystem response to intensive silvicultural treatments (blading of the organic layer, fertilization, herbicide application) in a Great-Lakes St-Lawrence mixedwood forest was initiated in 1986, in the Petawawa Research Forest north of Ottawa, Canada. From plantation age 9 to 13 we examined both litterfall and decomposition rates under six different intensive silviculture regimes that created contrasting environmental conditions. During the 5-yr study, interannual variation in litterfall was significant for pine litter, but not for deciduous litter. Total litterfall was lowest in 1998 when this region experienced an important water deficit. Intensive herbicide application (four consecutive years) reduced mean litterfall of deciduous litter over the 5-yr period by more than ten times (from 1140 kgha-1yr-1 to less than 100 kgha-1yr-1) and increased pine litter by more than five times (from 210 kgha-1yr-1 to 1100 kgha-1yr-1). Removal of the organic humus by blading did not affect the deciduous or coniferous litterfall. Decomposition rates of pine seedling needles and roots (litter quality constant) generally increased in response to silvicultural treatments.
Key words: litterfall, decomposition, plantation, Pinus strobus