HR: 15:10h
AN: B12E-07    [PDF]
TI: Changes in Carbon Storage and Net Carbon Exchange After a Shelterwood Harvest at Howland Forest, Maine
AU: * Scott, N A
EM: nscott@whrc.org
AF: Woods Hole Research Center, PO Box 296, Woods Hole, MA 02543 United States
AU: Rodrigues, C A
EM: crodrigues@maine.edu
AF: University of Maine, Department of Plant, Soil, and Environmental Science, Orono, ME 04469 United States
AU: Hughes, H
EM: rpt358@maine.edu
AF: University of Maine, Department of Plant, Soil, and Environmental Science, Orono, ME 04469 United States
AU: Lee, J T
EM: jtlee@maine.edu
AF: University of Maine, Department of Plant, Soil, and Environmental Science, Orono, ME 04469 United States
AU: Davidson, E A
EM: edavidson@whrc.org
AF: Woods Hole Research Center, PO Box 296, Woods Hole, MA 02543 United States
AU: Dail, D B
EM: bryan.dail@maine.edu
AF: University of Maine, Department of Plant, Soil, and Environmental Science, Orono, ME 04469 United States
AU: Goltz, S M
EM: goltz@maine.edu
AF: University of Maine, Department of Plant, Soil, and Environmental Science, Orono, ME 04469 United States
AU: Malerba, P
EM: Phil.Malerba@ipaper.com
AF: International Paper, 9 Green Street, Augusta, ME 04330 United States
AU: Hollinger, D Y
EM: davidh@hypatia.unh.edu
AF: USDA Forest Service Northeastern Research Station, 271 Mast Road, Durham, NH 03824 United States
AB: While many forests are actively sequestering carbon, little research has examined the direct effects of forest management practices on carbon sequestration. This is a critical issue in North America, where a large proportion of forests are managed. At the Howland Forest in Maine, we are using eddy covariance, biometric techniques and modeling to evaluate changes in carbon storage following a shelterwood cut that removed just under 30% of aboveground biomass. This management regime is becoming increasingly common throughout the region. Prior to harvest, the stand contained about 76 Mg C ha$^{-1}$ (30 m$^{2}$ha$^{-1}$ basal area) in above- and below-ground live biomass. Harvesting removed about 15 Mg C ha$^{-1}$ (SEM=2.1), and created about 5.3 Mg C ha$^{-1}$ (SEM=1.1) of aboveground and 5.2 Mg C ha$^{-1}$ (SEM=0.7) of root/stump detritus. Leaf-area index and litterfall declined by about 40% with harvest. Approximately half of the harvested wood was used for paper products (half-life of 3.5 years) and half for longer-lived wood products (half-life of 45 years). In a nearby, unharvested stand, eddy covariance measurements indicated that net ecosystem exchange (NEE) averages about 1.8 Mg C ha$^{-1}$ y$^{-1}$. A comparison of NEE at unharvested and harvested stands, both pre- and post-harvest, indicated that NEE declined following the harvest by about 18%, which is less than expected based on basal area and LAI changes. Both daily uptake and nocturnal respiration declined after harvest. Soil respiration declined slightly with harvest, suggesting no major soil C loss after harvest; harvesting had little effect on soil moisture and temperature. When decay of paper and wood products is included in a preliminary carbon budget, we predict that the forest will be a net C source to the atmosphere for at least 5 years, assuming pre-harvest growth rates of trees. How quickly the carbon balance becomes positive will depend largely on whether post-harvest tree growth rates increase.
DE: 0400 Biogeosciences
DE: 1600 GLOBAL CHANGE (New category)
DE: 1615 Biogeochemical processes (4805)
SC: Biogeosciences [B]
MN: 2003 Fall Meeting