The Effects of Mechanical Site Preparation and Subsequent Wildfire on Trembling Aspen (Populus Tremuloides Michx.) Regeneration in Central Alberta, Canada

Abstract

The objective of this study was to assess the regeneration response oftrembling aspen (Populus tremuloides Michx.) to differentmechanical site preparation (MSP) techniques commonly used in operationalforestry (disc trenching, drag scarifying and blading) and the specificmicrosites created by each treatment. This study was designed to measureregeneration after at least the first two growing seasons, however a largewildfire burned 80% of the study sites at the beginning of the second growingseason. Consequently, only limited second year data were presented, butregeneration from the first growing season following the fire was alsoassessed.Results indicated that microsites where the forest floor was disturbed and theparent root system was only lightly injured were more conducive to suckeringthan undisturbed microsites or where the root system was severely injured.Also,the fire disturbance after the first growing season resulted in increasedsuckering relative to the untreated controls in the first year. These resultssuggest that aspen sites with thick organic layers or vigorous competition fromother species can benefit from MSP when applied before the first growingseason.In addition, if first year suckering is inadequate, subsequent disturbancessuchas prescribed fire have the potential to improve suckering provided the parentroot system remains intact.