Forest vegetation species depend on a host of environmental conditions in ways that are unique for a given species; and vegetation can be adversely affected by air pollution (e.g., N and S deposition and ozone concentrations) and climate-related variables. Previous efforts have been made to statistically relate tree growth and survival to a limited set of these drivers. Additional potential drivers and statistical methods are currently under consideration. The occurrence probability of forest understory and other herbaceous vegetation species has also been evaluated across 165 National Parks using statistical models. This presentation will highlight progress towards consideration of an expanded set of explanatory variables for modeling species-level tree growth and survival to include additional drivers based on a hierarchical Bayesian technique for model parameterization. Additionally, model results related to forest understory and vegetation response to changes in N deposition and air temperature for a broad set of National Parks will be presented.

¹ E&S Environmental, Corvallis, OR

² U.S. Environmental Protection Agency, Office of Research and Development, Center for Public Health and Environmental Assessment, Washington, DC

³ National Park Service, Air Resources Division, Denver, CO

* Corresponding Author: todd.mcdonnell@esenvironmental.com