A Handbook of Tree Species Responses to Nitrogen Deposition

Robert D. Sabo1, Christopher Clark2, Linda Pardo3, Tara Greaver4, Jeffrey Herrick5, Kevin Horn6, Quinn Thomas7 and Linda Geiser8

Trees provide a variety of ecosystem good and services that are vital to maintaining the social, economic, and environmental well-being of our nation. A variety of anthropogenic and natural stressors, however, compromise the growth, recruitment, and survival of many forest tree species. These stressors, like drought, fire, pest outbreaks, and overharvesting, undermine the ecological processes that maintain the goods and services we derive from trees and forests. Atmospheric deposition of nitrogen (N) is one primary, anthropogenic stressor to tree species that alters tree growth rates, accelerates soil acidification, increases nitrate (NO3-) leaching which impairs downstream surface waters, and compromises important tree and mycorrhizal relationships. Implementation of the Clean Air Act and the 1990 Amendments has resulted in steadily declining emissions of oxidized N (NOx), and has resulted in significant declines in deposition across much of the eastern United States. Rates of atmospheric N deposition are still high relative to preindustrial times, however. This fact warrants an updated assessment of individual tree species’ vulnerabilities to current rates of deposition across the USA and associated alteration of ecological processes and ecosystem goods and services. The purpose of this report is to summarize the potential impacts from N deposition on 89 tree species across the continental US for which there is sufficient data to draw statistically robust conclusions about ecological impacts.  Inferences are drawn from the species-specific national-scale growth and mortality responses developed in Horn et al. (en prep), combined with ecological and ecosystem service information mainly acquired through the Fire Effects Information System. Together these provide information on how each species responds to N deposition, as well as the ecology and ecosystem services provided by these species. Specifically each species page presents five categories of information: (1) the reported range and abundance, (2) the associated N deposition across that range, (3) the species’ growth and mortality responses to N deposition, (4) a basic description of the ecology of and ecosystem processes supported by the species, and (5) a summary of the ecosystem goods and services provided by the species. This report will be a valuable, accessible reference manual for land managers and policy makers looking to assess species vulnerability to atmospheric N deposition, but also useful for economic and environmental researchers needing a centralized, succinct compendium describing species-specific ecological processes, ecosystem services, and datasets relevant to assessing tree species response to atmospheric N deposition.

 

1ORISE, EPA, Sabo.Robert@epa.gov
2EPA, Clark.Christopher@epa.gov
3USFS, lpardo@fs.fed.us
4EPA, Greaver.Tara@epa.gov
5EPA, Herrick.Jeffrey@epa.gov
6Virginia Tech, kjhorn@vt.edu
7Virginia Tech, rqthomas@vt.edu
8USFS, lgeiser@fs.fed.us