The condition and trend of aspen, Populus tremuloides, in Kootenay and Yoho National Parks: Implications for ecological integrity

Abstract

Aspen (Populus tremuloides) communities were measured in and near Yoho and Kootenay National Parks to determine condition and trend. Most aspen stands were heavily invaded by conifers as they had not burned in 60 years or more due to modern fire suppression and the elimination of aboriginal burning. Aspen is also declining due to repeated ungulate browsing, primarily by Elk (Cervus elaphus). Even where disturbed by logging and burning outside the parks, many aspen stands failed to produce new stems greater than 2 m tall because all the suckers were repeatedly browsed. Only where ungulate numbers were low was aspen able to successfully regenerate. Aspen, though, is not 'seral', as that term is commonly used because the species seldom grows from seed due to its demanding seed bed requirements. This, coupled with high biodiversity, makes aspen an excellent indicator of ecological integrity as mandated by Parks Canada statute.