Forest and Atmosphere Interactions
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Ecophysiology of Tropical Trees
Are Amazon old-growth forests net carbon sinks?
Wind Disturbance and Amazon Forest Ecology
Hurricane Impacts on Forests
Sea Level Rise Effects on Coastal Trees
Reforestation in Mata Atlantica
How old are tropical trees?

View from the top of a 65 meter tower in the Central Amazon at dawn.  A network of these towers have been established across the Amazon basin as part of the Brazilian-led LBA project, with the goal improving our understanding of the ecology, biogeochemistry, climatology, and hydrology of the Amazon basin.
stem respiration

Contact Information

Jeff Chambers
Tulane University
Ecology and Evolutionary Biology
400 Lindy Boggs
New Orleans, LA  70118
Ph:   504-862-8291
Fax:: 504-862-8706
chambers@tulane.edu

The carbon balance of old-growth tropical forests is important from the perspective of the atmospheric concentration of carbon dioxide.  There is clear evidence that deforestation in the Amazon is a large net source of CO2 to the atmosphere, but the role of old-growth forests remains contentious.  Our lab group has carried out a number of projects to better understand carbon cycling in old-growth Amazon forests.  One large project  was detailed in an ecosystem respiration paper, which included studies of environmental factors that control variability in CO2 exchange with the atmosphere (Chambers et al. 2004a).  This synthesis paper included new measurments of autotrophic and heterotrophic respiration, and also integrated work from previous projects including: (i) coarse litter (dead tree) decomposition (Chambers et al. 1998), (ii) respiratory activity from coarse litter (Chambers et al. 2001b), and (iii) net primary productivity (NPP) and tree allometry based on over 300 harvested trees (Chambers et al. 2001c). 

Another line of work focusing on the carbon balance of old-growth Amazonian forests involved the development of an individual-based stochastic-empirical model (coded in Java) to simulate the carbon cycling dynamics of live and dead trees.  Model results predicted that Central Amazon forests have a long-term carbon sink capacity, although the ability of these forests to mitigate the
anthropogenic
rise in atmospheric CO2  is quite limited  (Chambers et al. 2001d).  Chambers et al. (2004b) provides details of the model, and forest response to distrubances such as elevated tree mortality rates.