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

The effect of fire date on post-fire legacies in north-western Ontario red pine (Pinus resinosa) mixedwoods.

Woodman, Brett^*,1, Suffling, Roger¹, ¹ The School of Planning, Waterloo, On N2L 3G1, Canada

ABSTRACT- Prescribed burns are employed in the southern boreal forest of northwest Ontario, Canada, as a method of re-instating fire in this fire-dependent landscape. They are also used to manage fuel loads associated with long-term fire suppression, tree mortality from defoliating insects and from blow-downs, as well as in site preparation following harvest. The natural fire season in boreal Canada, with its usually stand replacing events, typically runs from April through September. However, prescribed burns in north-western Ontario are mostly scheduled for October when fire crews and equipment are available and fire hazard is reduced. We examined three recent spring, summer, and fall prescribed burns to assess the effect of season on post-fire legacies in red-pine mixedwood stands in Quetico Provincial Park, north-western Ontario. Legacies were assessed by tree, shrub and herb species composition, and by measurements of structure such as litter depth, basal areas of live trees and coarse woody debris. Tree species diversity was nearly identical. Post-fire stand structure varied widely between the different sites. The spring treatment experienced the least mortality of trees (10% of basal area dead); the summer treatment had the highest mortality (100%); and the fall prescribed burn was intermediate with 49% dead. The effect on the forest of the fall burn was probably more intense than that of a comparable natural fall fire because of the way in which it was managed, thus partly compensating for the late season. The ecological and policy implications will be discussed.

Key words: Fire, Boreal forest, Prescribed burn, Legacy