PARENT SESSION
Thursday, August 10, 8:00-11:30 am
COS 86 - Fire ecology: behavior, effects, and management
L-12, Lobby Level, Cook Convention Center
Presiders: N Turrill Welch and J Beyers

Vegetation mediated fire behavior determines succession pathway of boreal mixedwood forest.

Wang, Geoff^*,1, ¹ Clemson University, Clemson, SC

ABSTRACT- The role of disturbance in shaping vegetation pattern and dynamics has been well recognized, and recently considered by many studies. Unlike other physical disturbances, fire is greatly influenced by vegetation feedback. How does vegetation mediated fire behavior affect post-fire vegetation re-organization? We hypothesize that vegetation mediated fire behavior perpetuate individuals and stands in the same places in boreal mixedwood forest dominated by aspen (Populus tremuloides) and white spruce (Picea glauca). To test this hypothesis, we investigated early post-fire vegetation dynamics in response to fire severity using the 1999 Black River fire in Manitoba, Canada. Our results indicated that (1) fire severity was controlled by tree species composition through its influences on fuel status (i.e., quantity, quality and moisture), (2) seedbed conditions were controlled by fire severity through its direct duff consumption and indirect effects on competing vegetation, and (3) post-fire tree regeneration was regulated by fire severity through its influences on the survival of soil propagules or the receptivity of post-fire seedbeds. These results, when considered together, clearly suggest that aspen dominated patches favor aspen perpetuation while white spruce dominated patches favor post-fire establishment of white spruce.

Key words: Fire ecology, Succession, Boreal forest