Long-term Changes in Forest Carbon and Nitrogen Cycling Caused by an Introduced Pest/Pathogen Complex

Gary M. Lovett, Mary A. Arthur, Kathleen C. Weathers, Jacob M. Griffin

Research output: Contribution to journalArticlepeer-review

59 Scopus citations


Invasion of exotic forest pests and pathogens is a serious environmental problem for many forests throughout the world, and has been especially damaging to forests of eastern North America. We studied the impacts of an exotic pest/pathogen complex, the beech bark disease (BBD), in the Catskill Mountains of New York State, USA. In this region, BBD has caused a decline in the basal area of American beech (Fagus grandifolia Ehrh.) over the last 60 years and this decline has been accompanied by an increase in the basal area of sugar maple (Acer saccharum Marsh.). We studied the impacts of the BBD on carbon (C) and nitrogen (N) cycling using a series of stands that represented a sequence of disease impact and beech replacement by sugar maple. Our study showed that these long-term changes in tree species composition can lead to important changes in C and N cycling in the ecosystem, including an increase in litter decomposition, a decrease in soil C:N ratio, and an increase in extractable nitrate in the soil and nitrate in soil solution. Rates of potential net N mineralization and nitrification did not change across the BBD sequence, but the fraction of mineralized N that was nitrified increased significantly. Many of the observed changes in ecosystem function are larger in magnitude than those attributed to climate change or air pollution, suggesting that the impacts of invasive pests and pathogens on tree species composition could be one of the most important factors driving changes in C and N cycling in these forests in the coming decades.

Original languageEnglish
Pages (from-to)1188-1200
Number of pages13
Issue number8
StatePublished - Dec 2010

Bibliographical note

Funding Information:
We thank Dr. Ross Fitzhugh for the lysimetry analyses, Dr. Richard April for the XRF Ca analyses, and Jessica Hancock, Brent Mellen and Millie Hamilton for help in the field and laboratory. This research was supported by the U.S. National Science Foundation (Grants DEB 99-81503 and 04-44895). This is a contribution to the program of the Cary Institute of Ecosystem Studies.


  • American beech
  • Catskill Mountains
  • beech bark disease
  • calcium
  • carbon
  • forest
  • nitrogen
  • nutrient cycling
  • pathogen
  • pest
  • soil

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Environmental Chemistry
  • Ecology


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