CARBON DIOXIDE FLUXES IN A CENTRAL HARDWOODS OAK-HICKORY FOREST ECOSYSTEM
By:
Pallardy, Stephen; Gu, Lianhong ; Hanson, Paul J; Meyers, T.; Wullschleger, Stan D; Yang, Bai ; Hosman, K.
Page Number:
13-20
Book Title:
Proceedings, 15th Central Hardwood Forest Conference, Knoxville, TN February 27-March 1, 2006
Publication Date:
July 16, 2007
Conference Name:
15th Central Hardwood Forest Conference
Conference Location:
Knoxville, Tennessee, United States of America
Conference Sponsor:
University of Tennessee, USDA Forest Service
Abstract
A long-term experiment to measure carbon and water fluxes was initiated in 2004 as part of the Ameriflux network in a second-growth oak-hickory forest in central Missouri. Ecosystem-scale (~ 1 km2) canopy gas exchange (measured by eddy-covariance methods), vertical CO2 profile sampling and soil respiration along with meteorological parameters were monitored continuously. Early results from this forest located on the western margin of the Eastern Deciduous Forest indicated high peak rates of canopy CO2 uptake (35-40 ?mol m-2 s-1) during the growing season. Canopy CO2 profile measurements indicated substantial accumulation of CO2 (~500 ppm) near the surface in still air at night, venting of this buildup in the morning hours under radiation-induced turbulent air flow, and small vertical gradients of CO2 during most of the subsequent light period with minimum CO2 concentrations in the canopy. Flux of CO2 from the soil ranged from 2 to 8 ?mol m-2 s-1 and increased with temperature. Data from this site and others in the network will also allow characterization of regional spatial variation in carbon fluxes as well as inter-annual differences attributable to climatic events such as droughts.
