An Assessment of the Ecosystems of Nantahala-Pisgah National Forest & Surrounding Lands

link DOWNLOAD FILE: Assessment Report

Josh Kelly, Western North Carolina Alliance
Abstract: Ecological restoration has become one of the guiding principles of National Forest management. However, it can be difficult to identify a reference or desired condition as a restoration goal, and furthermore, accurately assessing ecosystem condition is dependent of the quality of the data available. LANDFIRE Biophysical Settings are computer models that combine scientific research, historical information, and expert opinion to describe the disturbance probabilities of ecosystems and simulate a Natural Range of Variation as a restoration target. Ecological zone maps are the most accurate ecosystem maps available for the Southern Blue Ridge Ecoregion and can be cross-walked to LANDFIRE Biophysical Settings. Light Detection and Ranging (LiDAR) data are recognized as one of the most comprehensive and accurate data for measuring vegetation structure.
A study area including the overlap of the 2005 Phase III North Carolina LiDAR data and the proclamation boundary of Nantahala-Pisgah National Forest was analyzed with the use of ecological zone maps, LANDFIRE Biophysical Settings, and LiDAR vegetation models. In total, over 700,000 hectares (1,760,000 acres) of forest were evaluated using LiDAR measured height and US Forest Service stand records to estimate forest age, and LiDAR measurements of canopy closure and shrub density to measure those physical characteristics.
Of 11 forest ecosystems evaluated, seven were found to be significantly departed from reference conditions. In general, ecosystems with a more frequent historical fire return interval were more departed from reference conditions than mesic forests and ecosystems with greater timber value were more disturbed than ecosystems with less economic value. For oak, cove and spruce ecosystems the Natural Range of Variation included a much higher proportion of old forests than the 2005 conditions, while the converse was true for shortleaf pine and pine-oak/heath ecosystems. Both oak and pine ecosystems had canopies that were much more closed than the reference models, while the canopies of cove ecosystems were more open than the reference models. Identifying over-abundant and under-abundant s-classes allows for prioritizing restoration and protection activities in each ecosystem and provides specific management goals for each ecosystem.
Locally modified LANDFIRE Biophysical Settings models were used as the ecological framework for the assessment.
update: the July 2013 version of this document was replaced
by the December 2013 version on 25 Mar 14