Watershed scale variability of nitrogen dynamics and related biogeochemical research at Noland Divide Watershed and associated spruce-fir sites
Nicholas N. 2016. Watershed scale variability of nitrogen dynamics and related biogeochemical research at Noland Divide Watershed and associated spruce-fir sites. National Park Service
PIs looked at watershed-scale variability of nitrogen dynamics at the Noland Divide watershed. Total litterfall was, on average, 40% needles, 20% deciduous foliage, and 40% twigs, bark, and reproductive tissues. Nitrogen uptake is correlated with measures of stand structure, but not with elevation or aspect. Coarse woody debris was a net source of nitrogen in early stages of decay and a net store or sink of nitrogen in later stages of decay. Dead wood volume was highly variable across the watershed. Standing and down dead biomass averaged 39.4 Mg per hectare and 33.8 Mg per hectare, respectively. Carbon concentrations remained relatively constant and were approximately 47% for all decay classes and all species. Nitrogen concentrations increased sharply between live wood and highly decayed wood. The nitrogen content in live wood, compared to wood in advanced decay, increased by 40% to 118% for the species tested. The magnitude of coarse woody debris in this system is among the highest reported in the literature for the eastern United States, emphasizing the high degree of disturbance that has taken place in this ecosystem. PIs examine soil nitrogen and carbon dynamics across 8 plots located between 1525 m and 1980m elevation (4 plots inside, 2 above, and 2 below Noland Divide Watershed) on similar aspects and having similar stand structure. Nitrogen mineralization rates differ among plots but do not follow a consistent pattern with elevation. Total carbon and nitrogen concentrations were highest in the organic O horizon, and generally decreased with depth in the mineral soil. A model for nitrogen cycling through this high elevation habitat was developed and calibrated.
- Type
- Generic Dataset
- Authors
- Nicholas, Niki
- Date of Issue
- 2016-10-11
- Publisher
- National Park Service
- Units
- GRSM
- Keywords
- APHN, Appalachian Highlands Network, Great Smoky Mountains National Park, GRSM, GRSM Permitted Study ID: GRSM-00180, GRSM-00175, SER, Southeast Region
- Subjects
- Ecological Framework: Biological Integrity | Focal Species or Communities | Forest/Woodland Communities