Nitrogen deposition and water stress: predisposing factors to southern pine beetle infestation and subsequent mortality of red spruce species, Mount Mitchell, NC
SUMMARY: Forests in western North Carolina receive some of the highest nitrogen deposition inputs in the southeastern U.S. Further, this area has also experienced a severe drought during the past five years. Chronic inputs of nitrogen deposition, stand density, and drought conditions may result in systematic changes in tree species and forest floor dynamics, thus making these species more susceptible to southern pine beetle infestation. To test this hypothesis, researchers will measure and examine the relationships between wood tissue Δ (‰), a measure of water stress, and variables that respond to chronic nitrogen deposition (e.g., basal area tree growth and forest floor and foliar chemistry) in two live and two dead high elevation spruce plots on Mount Mitchell, North Carolina. Results from this study will help to determine if Mount Mitchell spruce forests are water stressed and/or nitrogen saturated. Results will further determine if water stress and nitrogen saturation predisposed these forests to southern pine beetle attack and subsequent species mortality.
EFETAC's ROLE: The project is being led by EFETAC scientists and supported with EFETAC funding.
STATUS: Completed
PROGRESS:
McNulty, S.G. and J.L. Boggs. 2010. A conceptual framework: Redefining forest soil’s critical acid loads under a changing climate. Environmental Pollution 158:2053-2058. (PDF)
Left: Interactions among stressors contribute to forest decline and mortality. Click image to enlarge.
LINKS:
"Could Increasing Climate Variability Usher In “The Age of the Mediocre Forest?” (related article from CompassLive)
CONTACT:
- Steve McNulty, EFETAC Ecologist, steve.mcnulty@usda.gov or 919-549-4068
- Johnny Boggs, EFETAC Biological Scientist, johnny.boggs@usda.gov or 919-549-4060
Updated December 2011
