If a species’ success is defined by the size of its range, abundance and its influence on other organisms, then quaking aspen (Populus tremuloides Michx.) is among the most successful species on earth. It has an expansive range that covers much of the North American continent with high abundance across large portions of the boreal forest and Rocky Mountains. Theclosely related European aspen (Populus tremula L.) displays an even greater geographic extent across Eurasia. Aspen’s high genetic and phenotypic diversity, underlies its adaptability and resilience as a species and provides a richness of ways in which to interact and influence a broad community of biological organisms.
Plant communities with a dominant aspen component are often called aspen forests. This correctly emphasizes the central role that this single species has in shaping both the structure and function of the entire biological community that forms under its influence. Forest communities containing aspen are both structurally and functionally unique from other boreal and montane forest types. Aspen must be understood in a community context to fully appreciate its ecological role in the forests of North America.
We have implemented long-term studies to understand the changing ecology of aspen forest in response to human influences. Threats to the sustainability of aspen forest include: 1) longer fire intervals partly due to fire suppression policies leading to greater competition with conifers; 2) drought events that are expected to intensify with climate warming; and 3) heavy browse pressure by livestock and wildlife. A major research goal in our lab is to understand how these factors modify aspen forests and how that feeds back on the ecosystems services (e.g. high water yields) that properly aspen forests provide to human society.