Influence of post-harvesting residual stand structure on canopy light transmittance in ontario’s boreal mixedwood forests

A lack of local and regional markets for trembling aspen (Populus tremuloides Michx.) and white birch (Betula papyrifera Marsh.) can result in large numbers of merchantable-size hardwood stems with little commercial value, which complicates even-aged management of Ontario’s boreal mixedwood forests. To help identify potential management approaches to address this periodic economic situation, the relationship of stand structure with canopy transmittance was examined in recently harvested boreal mixedwood stands with differing hardwood tree retention levels. Canopy transmittance and residual stand structural features were measured in 483, 0.612 ha circular plots established in recently harvested stands in 12 locations across northern Ontario. For both trembling aspen- and white birch-dominated residual stands, canopy transmittance exhibited a negative exponential relationship with basal area, density, and stand density index. Nonlinear mixed effects models sometimes differed significantly between these two ...