PARTNERS: USDA Forest Service Northern Research Station

SUMMARY: The effects of nitrogen deposition on the health and productivity of high elevation spruce-fir forests have been concerns for several decades in Europe and the U.S. Recent studies have suggested that nitrogen deposition may also have negative impacts on the health of deciduous forests. Researchers will establish a series of plots in deciduous forests to test this hypothesis; the plots will be sampled adjacent to spruce-fir plots originally established in 1987 and 1988 across a nitrogen deposition gradient in the northeastern U.S. A subset of the spruce-fir plots will also re-sampled. Foliar and forest floor samples will be collected from 70 spruce-fir and 60 deciduous plots at different elevations and aspects to evaluate how both forest types are responding to equal doses of nitrogen deposition and to determine if the ecological state of the original spruce-fir plots has changed during the past 12 years. Results from this study will give a regional perspective on the influence of nitrogen deposition on forest floor and foliar chemistry in deciduous forests and show how high elevation spruce-fir forests are changing across graduated levels of nitrogen deposition in the northeastern U.S. 

STATUS: Completed

PROGRESS:

Boggs, Johnny L., McNulty, Steven G., and Pardo, Linda H. 2007. Changes in conifer and deciduous forest foliar and forest floor chemistry and basal area tree growth across a nitrogen (N) deposition gradient in the northeastern US. Environmental Pollution 149: 303-314. (PDF)

Pardo, Linda H., McNulty, Steven, G., Boggs, Johnny L., and Duke, Sara. 2007. Regional patterns in foliar ¹⁵N across a gradient of nitrogen deposition in the northeastern US. Environmental Pollution 149: 293-302. (PDF)

LINKS: USDA Forest Service Northern Research Station

CONTACT: Johnny Boggs, EFETAC Southern Global Change Program Biological Scientist, jboggs@ncsu.edu or 919-513-2973