A conceptual model to evaluate potential watershed nitrogen saturation in the Great Smoky Mountains
- Tennessee Valley Authority, Norris, TN (United States)
- Utah State Univ., Logan, UT (United States)
- Univ. of Tennessee, Knoxville, TN (United States)
Even though Title IV of the 1990 Clean Air Act Amendments requires significant reduction in utility nitrogen oxides emissions, the recent 1995 EPA Acid Deposition Standard Feasibility Study Report to Congress assumes that watersheds in the Southern Blue Ridge Province will eventually reach nitrogen saturation given historic and current deposition rates. Because of high atmospheric deposition levels (i.e., N loadings {approximately} 1900 eq/ha/yr 30 kg/ha/yr), much focus has been centered on the high elevation forests in the Southern Appalachians. Most nitrogen saturation scenarios focus on steady state forest conditions with little consideration for the role of natural disturbance regimes. However, in recent years, at least partly due to exotic insect infestation, the high elevation spruce-fir forests (Picea rubens-Abies fraseri) in the Smokies have developed a heterogeneous structure with numerous gaps and a large variation in stand age, number of live and dead standing trees, and amount of coarse woody debris on the forest floor. Assessment of nitrogen saturation status in this type of disturbed system requires more than a simple calculation of nitrogen input and export levels. This multi-year research, which has been funded by the National Park Service, the Tennessee Valley Authority, the US Department of Agriculture, and the US Geological Survey includes measurement of the three categories of factors that control nitrogen saturation including external (atmospheric) inputs, soil properties, and vegetation characteristics. The authors will discuss a conceptual model for a high elevation watershed in the Great Smoky Mountains National Park to examine potential nitrogen saturation in disturbed systems based on soil nitrogen levels, input and output fluxes, and quantification of potential nitrogen source and sink areas within the catchment.
- OSTI ID:
- 679367
- Report Number(s):
- CONF-980632-; TRN: IM9940%%186
- Resource Relation:
- Conference: 91. annual meeting and exhibition of the Air and Waste Management Association, San Diego, CA (United States), 14-18 Jun 1998; Other Information: PBD: 1998; Related Information: Is Part Of Proceedings of the 91. annual meeting and exhibition. Bridging international boundaries: Clean production for environmental stewardship; PB: [5000] p.
- Country of Publication:
- United States
- Language:
- English
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