Website Maps Air Pollution Threats To Forests

Research Issue

Screenshot from featured website - map of northeastern USA shows nitrogen deposition and paper birch critical loads.

Land managers and regulatory agencies are becoming increasingly aware of the impacts and threats posed by air pollution and nitrogen deposition on future forest health. The U.S. Forest Service’s 2012 Planning Rule, which contains required components for inclusion in the land management plans of all 154 national forests, specifically includes a section mandating the analysis of air quality impacts.

Researchers with the Northern Research Station and their collaborators have developed a web-based tool that will allow land managers in New England and the Great Lake states to more easily and accurately predict air quality impacts on their forests.

Our Research

The Nitrogen Critical Loads Assessment by Site website is the outgrowth of the Northern Research Station’s 2011 general technical report “Assessment of Nitrogen Deposition Effects and Empirical Critical Loads of Nitrogen for Ecoregions of the United States.” The website focuses on the sensitivity to nitrogen of 23 tree species common to three U.S. ecoregions comprising the Northeast and Great Lakes states.

The website interfaces with the Forest Service’s Forest Inventory and Analysis data, allowing users to analyze effects and critical load levels at such a fine scale as a 100-square foot parcel of land. Critical loads—the threshold before nitrogen deposition becomes harmful—can be assessed for a specific tree species, a combination of species, or a geographic area.

Expected Outcomes

The website allows land managers to quickly assess how much risk nitrogen deposition poses to forests under a number of current or future scenarios. The website can generate results in the form of high-resolution maps, graphics, and tables.

The data used by the website to calculate projections are available to land managers for other customizable searches, such as an area’s soil chemistry, elevation, temperature, and precipitation. Combined, the information can give land managers valuable insights into how to optimize growth in an area while mitigating the effects of nitrogen deposition.

Research Results

Pardo, Linda H.; Coombs, Jason A.; Robin-Abbott, Molly J.; Pontius, Jennifer H.; D'Amato, Anthony W. 2019. Tree species at risk from nitrogen deposition in the northeastern United States: A geospatial analysis of effects of multiple stressors using exceedance of critical loads. Forest Ecology and Management. 454: 117528-. https://doi.org/10.1016/j.foreco.2019.117528.

Robin-Abbott, Molly J.; Pardo, Linda H. 2017. How climatic conditions, site, and soil characteristics affect tree growth and critical loads of nitrogen for northeastern tree species. Gen. Tech. Rep. NRS-172. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 143 p. https://doi.org/10.2737/NRS-GTR-172.

Duarte, N.; Pardo, L.H.; Robin-Abbott, M.J. 2013. Susceptibility of forests in the northeastern USA to nitrogen and sulfur deposition: critical load exceedance and forest health. Water, Air and Soil Pollution. 224: 1355. DOI: 10.1007/s11270-012-1355-6. https://doi.org/10.1007/s11270-012-1355-6.

Pardo, L.H.; Robin-Abbott, M.J.; Driscoll, C.T., eds. 2011. Assessment of Nitrogen deposition effects and empirical critical loads of Nitrogen for ecoregions of the United States. Gen. Tech. Rep. NRS-80. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 291 p. https://doi.org/10.2737/NRS-GTR-80.

Research Participants

Principal Investigator

  • Linda Pardo, USDA Forest Service Northern Research Station, Environmental Engineer

Research Partners

  • Jason Coombs, University of Massachusetts, Amherst, Researcher
  • Jennifer Pontius, University of Vermont Rubenstein School of Environemnt and Natural Resources, Research Associate Professor
  • Molly Robin-Abbott, USDA Forest Service Northern Research Station, Contractor
  • Last modified: December 8, 2020