Carbon Sources and Sinks in High-Elevation Spruce-Fir Forests in the Southeastern US

Authors

H. Van Miegroet, Utah State University
P. Moore
C. Tewksbury
N. S. Nicholas

Document Type

Article

Journal/Book Title/Conference

Forest Ecology and Management

Volume

238

Issue

1-3

Publisher

Elsevier

Publication Date

2007

Keywords

carbon, sources, sinks, high-elevation, spruce-fir forests, southeastern United States

First Page

249

Last Page

260

Abstract

This paper examines carbon (C) pools, fluxes, and net ecosystem balance for a high-elevation red spruce–Fraser fir forest [Picea rubens Sarg./Abies fraseri (Pursh.) Poir.] in the Great Smoky Mountains National Park (GSMNP), based on measurements in fifty-four 20 m × 20 m permanent plots located between 1525 and 1970 m elevation. Forest floor and mineral soil C was determined from destructive sampling of the O horizon and incremental soil cores (to a depth of 50 cm) in each plot. Overstory C pools and net C sequestration in live trees was estimated from periodic inventories between 1993 and 2003. The CO2 release from standing and downed wood was based on biomass and C concentration estimates and published decomposition constants by decay class and species. Soil respiration was measured in situ between 2002 and 2004 in a subset of eight plots along an elevation gradient. Litterfall was collected from a total of 16 plots over a 2–5-year period. The forest contained on average 403 Mg C ha−1, almost half of which stored belowground. Live trees, predominantly spruce, represented a large but highly variable C pool (mean: 126 Mg C ha−1, CV = 39%); while dead wood (61 Mg C ha−1), mostly fir, accounted for as much as 15% of total ecosystem C. The 10-year mean C sequestration in living trees was 2700 kg C ha−1 year−1, but increased from 2180 kg C ha−1 year−1 in 1993–1998 to 3110 kg C ha−1 year−1 in 1998–2003, especially at higher elevations. Dead wood also increased during that period, releasing on average 1600 kg C ha−1 year−1. Estimated net soil C efflux ranged between 1000 and 1450 kg C ha−1 year−1, depending on the calculation of total belowground C allocation. Based on current flux estimates, this old-growth system was close to C neutral.

Comments

Originally published by Elsevier. Publisher's PDF and HTML fulltext available through remote link.

Recommended Citation

Van Miegroet, H., P. Moore, C. Tewksbury, and N.S. Nicholas. 2007. Carbon sources and sinks in high-elevation spruce-fir forests in the Southeastern US. Forest Ecology and Management 238: 249-260.