Natural disturbance regimes and tropical forest carbon balance: integrating canopy structure, flux measurements, and modeling across the landscape
Scott
R.
Saleska, Harvard University, saleska@fas.harvard.edu
(Presenting)
Paul
R.
Moorcroft, Harvard University, paul_moorcroft@harvard.edu
David
Roy
Fitzjarrald, SUNY Albany, fitz@asrc.cestm.albany.edu
Geoffrey
G.
Parker, Smithsonian Environmental Research Center, parkerg@si.edu
Plínio
Barbosa de
Camargo, CENA, pcamargo@cena.usp.br
Steven
C.
Wofsy, Harvard University, scw@io.harvard.edu
Natural disturbance events play a critical role in the carbon cycling of tropical forests, and hence estimating carbon balance over large spatial scales depends on: (1) understanding how local carbon balance depends on local disturbance status and history; and (2) accurate characterization of the distribution of disturbance states across those larger spatial scales. Here we use ground-based lidar measurements of canopy height (Parker and Lefsky, 2004) to characterize local disturbance status of plots in the Tapajós National Forest of Brazil. Following the approach of Hurtt et al (2004), we then use the observed canopy height distribution to constrain a size-structured forest biogeochemistry model (the Ecosystem Demography model, ED). Finally, we compared the predictions of the constrained ED model to eddy flux and biometric estimates of ecosystem carbon balance at the local scale, and found that the model correctly predicts that the forest around the flux tower is a net carbon source to the atmosphere. This analysis suggests that remote-sensing based estimates of canopy height (like those that would be provided by NASA’s airborne Laser-Vegetation Imaging Sensor, LVIS, proposed to fly as part of LBA) can constrain model predictions of carbon balance at landscape scale. Such predictions could be independently tested at the landscape scale by measurements now underway (Santoni et al., this LBA meeting) in large-scale biomass plots spatially distributed across the Tapajós landscape.
Submetido por Scott Reid Saleska em 18-MAR-2004
Tema Científico do LBA: CD (Armazenamento e Trocas de Carbono)