HR: 10:20h
AN: B32B-01 INVITED    [Abstracts]
TI: The Effects of Disturbance on Forest Carbon Processes
AU: * Law, B
EM: bev.law@oregonstate.edu
AF: Oregon State University, 328 Richardson Hall, Corvallis, OR 97331, United States
AU: Noormets, A
EM: anoorme@ncsu.edu
AF: North Carolina State University, Department of Forestry and Environmental Resources, Raleigh, NC 27695, United States
AU: Grace, J
EM: jgrace@ed.ac.uk
AF: University of Edinburch, Institute of Atmospheric and Environmental Science, Edinburgh, EH93JN, United Kingdom
AB: We use data from flux sites to examine patterns of response to disturbance among forest types. Forest development is punctuated by disturbances associated with fire and harvest, which reduces photosynthesis and possibly increases microbial respiration. After stand-replacing disturbance, NPP tends to be low in early succession and heterotrophic respiration may be high, low, or relatively similar to that of undisturbed areas depending on the disturbance characteristics. Effects of wildfire differ from harvest in that wildfire leaves more standing dead trees that can take decades to fall, and charring reduces decomposition potential. High intensity fires can reduce soil respiration for several years due to root mortality and reduced microbial activity. Clearcut harvesting adds a large amount of dead plant material to the forest floor immediately, which may be left on-site or partially remove through management activities. These factors differentially affect the trajectory of respiration rates over time. Differences may also exist between productivity rates after disturbance associated with natural succession and tree planting. In addition, carbon allocation patterns change with time since disturbance, altering above- and belowground sources and sinks. The balance of these processes is net ecosystem production (NEP), and variation in regeneration, mortality, and decomposition affect NEP over time. Process models and LUE models should consider these disturbance effects when mapping regional carbon balances.
DE: 0400 BIOGEOSCIENCES
DE: 0428 Carbon cycling (4806)
DE: 0439 Ecosystems, structure and dynamics (4815)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting