Mid-Atlantic Forests and the Chesapeake Bay Watershed
Forest landscapes are changing as a consequence of climate and environmental change. These changes affect people and the forest ecosystems they depend on for clean water, clean air and forest products, and recreation. How can we best manage our forest resources to sustain this array of ecosystem services under increasing environmental stress and a changing climate?
The Northern Research Station has a long history of research on the effects of air pollution and climate change on forests of the Northeastern and North Central United States. We have documented climate trends, increasing atmospheric carbon dioxide, ozone exposure, high levels of acid and nitrogen deposition, and land use pressures, all simultaneously affecting northern forests. We observe that in the past, northern forests have shown remarkable resiliency and adaptability to high levels of environmental stress. We build on this research background to evaluate management and policy options for adapting to global change, particularly strategies to maximize the role of northern temperate forests as sinks for carbon dioxide.
One of the most critical research needs is to improve our understanding of the effects of nitrogen deposition on water quality and carbon sequestration. Human effects on the natural cycle of nitrogen have caused significant alterations of land productivity, freshwater quality, and marine ecosystems. Nitrogen compounds generated by human activities are transported by the atmosphere and deposited to ecosystems. Healthy forests perform the service of removing much of the deposited nitrogen and storing it in plant tissues. In the Chesapeake Bay watershed, for example, forests retain 88% of deposited nitrogen, allowing only about 1 kg/ha/yr to leach into more sensitive aquatic ecosystems (Pan et al. 2004). As the level of deposition rises, the retention rate declines and the negative effects on downstream ecosystems increase. One positive consequence of nitrogen deposition is increased productivity of land ecosystems that are deficient in nitrogen availability. Net carbon uptake by forests of the Mid-Atlantic region may be increasing by 25% from nitrogen deposition; however, this rate of increase is reduced by ground-level ozone pollution, which is damaging to many plant species. The increasing concentration of atmospheric CO2 also is a factor in changing productivity.
We are beginning to understand how the interacting effects of climate change, elevated CO2, increasing ozone exposure, high levels of acid deposition, land use changes, and invasive pests change the growth and distribution of northern forests. We produce maps summarizing observed climate changes and disturbances such as insects and disease outbreaks, ozone exposure, and acid deposition. We develop projections of climate variability, fire weather, air pollution transport, and their effects on vegetation distribution and other important ecosystem properties such as bird species abundance or water yield. These projections can help identify effective response strategies.
The land we care for is changing in many ways. In order to develop effective strategies to adapt to these long-term changes, we need to better understand the interacting effects of a changing climate, air pollution, and other factors on forest productivity, water availability, and nutrient cycling. As these effects accumulate, we begin a new century with high uncertainty about future forest resource sustainability. Our research is leading to better ways to adapt to these pervasive changes and sustain the many services provided by the region’s forests.
Najjar, Raymond G.; Pyke, Christopher R.; Adams, Mary Beth; Breitburg, Denise; Hershner, Carl; Kemp, Michael; Howarth, Robert; Mulholland, Margaret R.; Paolisso, Michael; Secor, David; Sellner, Kevin; Wardrop, Denice; Wood, Robert. 2010. Potential climate-change impacts on the Chesapeake Bay. Estuarine Coastal and Shelf Science. 86:1-20.
Adams, Mary B.; DeWalle, David R.; Hom, John L. 2006. Conclusions and recommendations from the Fernow Watershed Acidification study. In: Adams, Mary B.; DeWalle, David R.; Hom, John L., eds. The Fernow watershed acidification study. Dordrecht, , Netherlands: Springer: 11: 259-268.
Dewalle, David R.; Hom, John L.; Adams, Mary B. 2006. Introduction to the Fernow Watershed Acidification Study. In: Adams, Mary B.; DeWalle, David R.; Hom, John L., eds. The Fernow watershed acidification study. Dordrecht, , Netherlands: Springer: 11: 1-15.
Hom, John L.; Pan, Yude; McCullough, Kevin. 2006. Implications for forest ecosystem sustainability and resiliency. In: Adams, Mary B.; DeWalle, David R.; Hom, John L., eds. The Fernow watershed acidification study. Dordrecht, , Netherlands: Springer: 11: 237-254.
Pan, Yude; Birdsey, Richard; Hom, John; McCullough, Kevin; Clark, Kenneth. 2005. Improved estimates of net primary productivity from MODIS satellite data at regional and local scales. Ecological Applications. 16(1): 125-132.
Pan, Y; Hom, J; Birdsey, R; McCullough, K. 2004. Impacts of rising nitrogen deposition on N exports from forests to surface waters in the Chesapeake Bay Watershed. Environmental Management 33 (4) (Supplement):120-131.
- John Hom, Biological Scientist, US Forest Service Northern Research Station
- Yude Pan, Research Forester, US Forest Service Northern Research Station
- Richard Birdsey, Program Manager, US Forest Service Northern Research Station
- Mary Beth Adams, Research Soil Scientist, US Forest Service Northern Research Station
- David Dewalle, Pennsylvania State University
Last Modified: 02/17/2016