Post-disturbance dynamics of aspen mixed-woods: A comparison among fire, logging, and budworm outbreak (Populus tremuloides, Choristoneura fumiferana)

Seventy-one aspen (Populus tremuloidies Michx.) mixedwood stands disturbed in the 1980's were sampled in southeastern Manitoba, Canada to examine the response of arboreal and understory communities to natural and management-induced disturbances. Thirty stands were disturbed by severe spruce budworm (Choristoneura fumiferana Clem.) outbreaks, 21 by crown fire, and 20 by conifer-selective logging. All sampled stands were on well drained upland sites with similar pre-disturbance vegetation.; For the understory community, species diversity, richness, and presence did not differ significantly between the disturbance types. Significant differences, however, were found in species evenness with the understory of logged stands being dominated by shrubs. Coefficient of community was consistently greater than percent similarity, indicating that differences between disturbance types occur primarily in species abundance.; Due primarily to differential canopy removal both fire and logging disturbed stands were dominated by post-disturbance aspen regeneration and contained little conifer recruitment while spruce budworm disturbed stands had abundant conifer recruitment and significantly less aspen regeneration. (Abstract shortened by UMI.)...