A semi-natural approach to mixedwood management in the prairie provinces

Abstract

The white spruce-aspen mixedwood associations of the prairie provinces have a variety of possible compositions ranging from pure aspen to pure white spruce to mixtures of the two. Regulations and silvicultural treatments have been largely aimed at promoting the more commercially valuable white spruce, largely through plantation establishment and management. We feel that it is time to re-evaluate our current management of these mixedwoods for the following reasons: 1) Because of competition from hardwoods and grass, white spruce regeneration has been very expensive and only partly successful. 2) Hardwoods are now acceptable crop trees; the traditional conifer bias is now inappropriate and there are increasing possibilities for conflict between hardwood and softwood users of the same land base. 3) The increased understanding of forest ecosystems and a strong environmental movement have resulted in demands for management systems that are ecologically based.In future, management systems will likely move away from expensive single species plantation systems and promote more mixed forests. To retain the white spruce component of these forests, systems must be developed that enhance natural regeneration of lower densities of white spruce over a wider area. These must be coupled with refined harvesting techniques that protect spruce regeneration during the harvest of the aspen. Growth and yield models must accurately reflect the ecology of mixedwoods. Tenure systems should be structured to ensure that one manager has responsibility for silviculture prescription and harvest scheduling of a given area. The same manager, however, must ensure maintenance of the allowable cuts of each species and the biodiversity of the area. Key words: mixedwoods, silviculture, white spruce, aspen, biodiversity, ecosystem management.