Evaluating Aspen Decline and its Drivers
Throughout the world, there is growing concern that many tree species are in decline. These declines can take the form of large-scale tree mortality, contracting stand cover, and/or reduced recruitment and regeneration. The situation appears especially acute for quaking aspen (Populus tremuloides), which is the most widespread tree species in North America but is reportedly undergoing significant declines throughout much of its geographic range. These declines are particularly concerning given that aspen stands are biodiversity hotspots and provide a wide range of ecosystem services.
Our lab is addressing the patterns in and drivers of aspen performance across diverse landscapes in North America. We are resampling an extensive aspen plot network across five states in the intermountain west and, at a larger scale, are using FIA data, equivalent data from Canada, and 35 years of landsat imagery to assess the performance of aspen across its entire geographic range. We are particularly interested in understanding how the performance of aspen stands vary across its vast geographic range during a period of unprecedented human-caused climate change. We are also investigating the importance of invading conifers and mammalian herbivores (deer, elk and cattle) as drivers of aspen decline.