High Foliar and Soil Nitrogen Concentrations in Central Appalachian Forests

Abstract

Regional topography and climate variation yield differences in ecosystem attributes that make spatially scaled estimates of forest productivity challenging. Foliar nitrogen is a primary indicator of forest ecosystem productivity and is used in regional estimates of terrestrial productivity, but this characteristic has not been well described in the Central Appalachian region. Here we describe foliar and soil N variation among species and elevations at two spatial scales in the Central Appalachian region: (1) across the Elklick watershed in the Fernow Experimental Forest and (2) across the state of West Virginia. We found higher foliar N concentrations at both scales than those previously reported for other temperate forest regions. Canopy and soil nitrogen concentrations were also much greater in the Fernow than generally observed across West Virginia. Soil N concentrations in the Fernow were two times greater than those observed across West Virginia.Species-related differences were observed at both spatial scales, but were not always consistent. Canopy N ranges are generally consistent across elevations throughout the state of West Virginia, but should be scaled according to species-related elevation effects for studies that estimate productivity differences in response to harvest or changing species composition. The incongruence of foliar and soil N concentrations at the Fernow Experimental Forest are not explained by elevation or species composition, but are likely a consequence of greater historical N and H + deposition relative to the surrounding West Virginia region.

Imaging spectroscopy algorithms for mapping canopy foliar chemical and morphological traits and their uncertainties

“…spectrum (Wright et al , 2005a. The positive correlation of foliar N with regional-scale N deposition corroborates evidence of foliar N enrichment reported in numerous studies in northeastern forests (McNeil et al 2007, 2012, Davis et al 2009, Crowley et al 2012). Correlations of foliar d 15 N concentrations with mean annual temperature (positive) and precipitation (negative) agree with results in Amundson et al (2003), Craine et al (2009), andSerbin et al (2014).…”

Forest carbon sequestration changes in response to timber harvest

“…Schuler (2004) also found that the interval of harvest was important for sustaining annual woody increment growth, but changes in wood production were partially mediated by changes in species composition. In another recent study, we found that the interaction of species and N availability has important implications for the sustainability of forest C stores in mature West Virginia forests (Davis et al, 2009). Here, we estimated C storage at the ecosystem scale, but it should be noted that biased timber species selections would influence the effect of harvests reported here.…”