Canadian Forest Service Publications
A functional framework for improved management of western North American aspen (Populus tremuloides Michx.). 2014. Rogers, P.C.; Landhäusser, S.M.; Pinno, B.D.; Ryel, R.J. Forest Science 60(2):345-359.
Issued by: Northern Forestry Centre
Catalog ID: 35075
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Quaking or trembling aspen (Populus tremuloides Michx.) forests occur in highly diverse settings across North America. However, management of distinct communities has long relied on a single aspen-to-conifer successional model. We examine a variety of aspen-dominated stand types in the western portion of its range as ecological systems, avoiding an exclusive focus on seral dynamics or single-species management. We build a case for a large-scale functional aspen typology based on the existing literature. Aspen functional types are defined as aspen communities that differ markedly in their physical and biological processes. The framework presented here describes two “functional types” and seven embedded “subtypes”: seral (boreal and montane), stable (parkland, Colorado Plateau, elevation and aspect limited, and terrain isolated), and a crossover seral-stable subtype (riparian). The assessment hinges on a matrix comparing proposed functional types across a suite of environmental characteristics. Differences among functional groups based on physiological and climatic conditions, stand structures and dynamics, and disturbance types and periodicity are described herein. We further examine management implications and challenges, such as human alterations, ungulate herbivory, and climate futures, that affect the functionality of these aspen systems. The functional framework lends itself well to stewardship and research that seek to understand and emulate ecological processes rather than combat them. We see advantages of applying this approach to other widespread forest communities that engender diverse functional adaptations.
Plain Language Summary
Quaking or trembling aspen — the most widely distributed tree in North America — was previously viewed as a “weed” tree that grows rapidly on cleared land and is slowly displaced by other vegetation as the forest matures. Management of aspen forests is based on such traditional views of the role of aspen in successional forests. This article argues that these views are oversimplified and fail to take into account the wide range of environments in which this tree grows. It proposes different “functional groups” based on the role that aspen plays in varied environments. The researchers conclude that aspen should be managed in a targeted way based on functional group, rather than in a “one-size-fits-all” approach. Such management would improve the resilience of aspen. It also fits with current views of forest stewardship based on emulating natural processes.