Growth and survival relationships of 71 tree species with nitrogen and sulfur deposition across the conterminous U.S

PLoS One. 2018 Oct 18;13(10):e0205296. doi: 10.1371/journal.pone.0205296. eCollection 2018.

Abstract

Atmospheric deposition of nitrogen (N) influences forest demographics and carbon (C) uptake through multiple mechanisms that vary among tree species. Prior studies have estimated the effects of atmospheric N deposition on temperate forests by leveraging forest inventory measurements across regional gradients in deposition. However, in the United States (U.S.), these previous studies were limited in the number of species and the spatial scale of analysis, and did not include sulfur (S) deposition as a potential covariate. Here, we present a comprehensive analysis of how tree growth and survival for 71 species vary with N and S deposition across the conterminous U.S. Our analysis of 1,423,455 trees from forest plots inventoried between 2000 and 2016 reveals that the growth and/or survival of the vast majority of species in the analysis (n = 66, or 93%) were significantly affected by atmospheric deposition. Species co-occurred across the conterminous U.S. that had decreasing and increasing relationships between growth (or survival) and N deposition, with just over half of species responding negatively in either growth or survival to increased N deposition somewhere in their range (42 out of 71). Averaged across species and conterminous U.S., however, we found that an increase in deposition above current rates of N deposition would coincide with a small net increase in tree growth (1.7% per Δ kg N ha-1 yr-1), and a small net decrease in tree survival (-0.22% per Δ kg N ha-1 yr-1), with substantial regional and among-species variation. Adding S as a predictor improved the overall model performance for 70% of the species in the analysis. Our findings have potential to help inform ecosystem management and air pollution policy across the conterminous U.S., and suggest that N and S deposition have likely altered forest demographics in the U.S.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Carbon / chemistry
  • Carbon / metabolism
  • Computer Simulation
  • Forests
  • Models, Statistical*
  • Nitrogen / chemistry
  • Nitrogen / metabolism*
  • Soil / chemistry
  • Sulfur / chemistry
  • Sulfur / metabolism*
  • Trees / chemistry
  • Trees / growth & development
  • Trees / metabolism*
  • United States

Substances

  • Soil
  • Sulfur
  • Carbon
  • Nitrogen

Grants and funding

Funding for this effort was provided by U.S. Environmental Protection Agency (Contract EP-W- 11-029; Work Assignment No. 4-16), U.S. Geologic Survey (U.S. Geologic Survey Powell Center Program), and the National Parks Service (Task Agreement Number P18AC01685). CMC (EPA) and GBL (USGS) contributed to the study design, interpretation now the analysis, decision to publish, and preparation of the manuscript. The Warby Group LLC provided support in the form of salaries for author WB, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.