Understanding How Acid Rain Affects Soil and Trees

Research Issue

Acid rain-induced calcium depletion predisposes red spruce to foliar winter injury (foliar death from freezing that makes needles turn reddish brown and fall off), which reduces growth and can lead to tree mortality.Trees exposed to acid rain may have unusually severe reactions to environmental stresses. Acid rain is defined as precipitation that’s unusually acidic as a result of pollution in the atmosphere. This pollution, which often contains sulfur dioxide or nitrogen oxides, can change soil chemistry by dissolving calcium and other nutrients and releasing aluminum, which makes it harder for trees to absorb water. Calcium can affect how trees’ cells respond to environmental stress and reduced soil calcium levels may increase the likelihood of aluminum poisoning.

Our Research

Northern Research Station scientists are finding out how calcium, nitrogen and aluminum affect microbial diversity, soil quality, photosynthesis, overall forest health, and tree responses to environmental stressors. We are also conducting tests to see if trees like paper birch are affected by acid rain, which has been connected to red spruce and sugar maple deaths. At the Hubbard Brook Experimental Forest in New Hampshire and Harvard Forest in Massachusetts, scientists are evaluating how red spruce and other tree species are responding to calcium applications across entire watersheds that have been exposed to acid rain over many years. More recent research involves computer modeling to help locate areas with high levels of acid rain.

Expected Outcomes

By helping scientists understand how calcium depletion and other soil chemistry changes affect different kinds of trees, this research will help land managers maintain and improve forest health in areas that have been exposed to acid rain.

Research Results

Fahey, Timothy J.; Schaberg, Paul G. 2019. Forest physiology and phenology. Chapter 14. In: Fahey, T.J., ed. Synthesis of scientific research at Hubbard Brook. Woodstock ,VT: Hubbard Brook Research Foundation.

Kosiba, Alexandra M.; Schaberg, Paul G.; Rayback, Shelly A.; Hawley, Gary J. 2018. The surprising recovery of red spruce growth shows links to decreased acid deposition and elevated temperature. Science of the Total Environment. 637-638: 1480-1491. https://doi.org/10.1016/j.scitotenv.2018.05.010.

Schaberg, P.G. 2017. Acid rain and sugar maple decline. Maple Syrup Digest. February:18-23.

Carter, T.; Clark, C.; Fenn, M.E.; Jovan, S.; Perakis, S.S.; Riddell, J.; Schaberg, P.G.; Hastings, M. 2017.  Mechanisms of nitrogen deposition effects on forest lichens and trees in the United States. Ecosphere. 8(3):e01717.10.1002/ecs2.1717.

Engel, B.J.; Schaberg, P.G.; Hawley, G.J.; Rayback, S.A.; Pontius, J.; Kosiba, A.M. ; Miller, E.K. 2016. Assessing relationships between red spruce woody growth and high-resolution pollution exceedance values. Forest Ecology and Management 359:83-91..

Halman, J.M., P.G. Schaberg, G.J. Hawley, C.F. Hansen, T.J. Fahey. 2015. Differential impacts of calcium and aluminum treatments on sugar maple and American beech growth dynamics. Canadian Journal of Forest Research 45:52-59.

Lawrence, Gregory B.; Hazlett, Paul W.; Fernandez, Ivan J.; Ouimet, Rock; Bailey, Scott W.; Shortle, Walter C.; Smith, Kevin T.; Antidormi, Michael R. 2015. Declining acidic deposition begins reversal of forest-soil acidification in the northeastern US and eastern Canada. Environmental Science & Technology. 49(22): 13103-13111. https://doi.org/10.1021/acs.est.5b02904

Halman, J.M.; Schaberg, P.G.; Hawley, G.J.; Pardo, L.H.; Fahey, T.J. 2013. Calcium and aluminum impacts on sugar maple physiology in a northern hardwood forest. Tree Physiology 33:1242-1251.

Boyce, R.L.; Schaberg, P.G.; Hawley, G.J.; Halman, J.M.; Murakami, P.F. 2013.  Effects of soil calcium and aluminum on the physiology of balsam fir and red spruce saplings in northern New England.  Trees 27:1657-1667.

Kosiba, A.M.; Schaberg, P.G.; Hawley, G.J.; Hansen, C.F. 2013. Quantifying the legacy of foliar winter injury on woody aboveground carbon sequestration of red spruce trees. Forest Ecology and Management 302:363-371.

Comerford, Daniel P.; Schaberg, Paul G.; Templer, Pamela H.; Socci, Anne M.; Campbell, John L.; Wallin, Kimberly F. 2013. Influence of experimental snow removal on root and canopy physiology of sugar maple trees in a northern hardwood forest. Oecologia. 171: 261-269.

Green, Mark B.; Bailey, Amey S.; Bailey, Scott W.; Battles, John J.; Campbell, John L.; Driscoll, Charles T.; Fahey, Timothy J.; Lepine, Lucie C.; Likens, Gene E.; Ollinger, Scott V.; Schaberg, Paul G. 2013. Decreased water flowing from a forest amended with calcium silicate. Proceedings of the National Academy of Science. 110(15): 5999-6003.

Schaberg, Paul G.; Minocha, Rakesh; Long, Stephanie; Halman, Joshua M.; Hawley, Gary J.; Eagar, Christopher. 2011. Calcium addition at the Hubbard Brook Experimental Forest increases the capacity for stress tolerance and carbon capture in red spruce (Picea rubens) trees during the cold season. Trees. 25: 1053-1061.

Halman, Joshua M.; Schaberg, Paul G.; Hawley, Gary J.; Hansen, Christopher F. 2011. Potential role of soil calcium in recovery of paper birch following ice storm injury in Vermont, USA. Forest Ecology and Management. 261: 1539-1545. 

Research Participants

Principal Investigator

  • Paul Schaberg, US Forest Service – Northern Research Station, Research Plant Physiologist

Research Partners

  • Paula Murakami, USDA-Forest Service – Northern Research Station, Biological Sciences Technician
  • Shelly Rayback, The University of Vermont, Associate Professor of Geography
  • Gary Hawley, The University of Vermont, Senior Researcher
  • Jennifer Pontius, The University of Vermont, Assistant Professor of Environmental Science
  • Christopher Hansen, The University of Vermont, Forestry Technician
  • Alexandra Kosiba, The University of Vermont, Forestry Lecturer and Research Specialist
  • Last modified: March 19, 2019