Abundances of Cavity-nesting Birds and their Dead Wood Resources in Closed-canopy Managed and Unmanaged Mixedwood Forests of Boreal Northeastern Ontario

In eastern boreal forests harvesting has displaced forest fires as the dominant disturbance, changing the natural age mosaic and reducing old-growth forest and standing dead wood supplies. Herein, eleven cavity nesting bird species and their habitats are compared among three stand histories (mid-rotation and mature regenerated stands (31-40 and 47-64 years post-harvest, respectively) and uncut forest (80+ years old)) surveyed in boreal mixedwood sites in northeastern Ontario. Yellow-bellied sapsucker, northern flicker and red-breasted nuthatch abundances were greater in uncut sites. While large live tree density and basal area increased with time since disturbance, a U-shaped pattern in large dead stem density was observed with old-cut sites having low supplies. Resource use based on breeding and feeding evidence was examined relative to availability and large dead trembling aspen was found to be important. Results indicate a diminished ability of post-harvest stands to supply similar habitat attributes to those of uncut forest.M.Sc