Hybrid Aspen Response to Shearing in Minnesota: Implications for Biomass Production

There is great potential for the production of woody biomass feedstocks from hybrid aspen stands; however, little is known about the response of these systems to silvicultural treatments, such as shearing. We sought to address this need by integrating results from more than 20 years of individual tree and yield measurements in hybrid aspen (Populus tremuloides Mich. × P. tremula L.) stands in north central Minnesota. Specifically, tree and stand-level responses are described in terms of sucker density, early diameter and height characteristics, volume, and biomass production. Overall, shearing treatments increased the density of hybrid aspen stems, relative to preshear densities at the same age. In addition, average stem diameter and volume as well as stand-level biomass were considerably greater in hybrid aspen stands relative to similarly aged native aspen stands also established via shearing treatment. These findings illustrate that coppice systems using hybrid aspen provide great potential to rapidly produce biomass feedstocks, with little management investment.