Characterizing a link in the terrestrial carbon cycle: a global overview of individual tree mass growth

Forests sequester the majority of the terrestrial biosphere’s carbon and are key components of the global carbon cycle, potentially contributing substantial feedbacks to ongoing climatic changes. It is therefore remarkable that no consensus yet exists about the fundamental nature of tree mass growth (and thus carbon sequestration rate). Specifically, does tree mass growth rate increase, decrease, or stay the same with increasing tree size? The answer could have profound implications for our ability to forecast the role of forests in the global carbon cycle and to devise appropriate adaptation and mitigation strategies for forests in the face of rapid climatic changes.

We will conduct the first global-scale characterization of the relationship between individual tree mass growth rate and tree size. To reach this end, we will analyze forest monitoring data from every forested continent, including millions of trees and more than 1,000 species. We have assembled an international team to accomplish this task, and have leveraged funds with the Smithsonian Tropical Research Institute’s Center for Tropical Forest Science.

Publications:
Das, A.J. (2012). The effect of size and competition on tree growth rate in old-growth coniferous forests. Canadian Journal of Forest Research, 42(11), 1983-1995. doi: 10.1139/x2012-142
Rüger, N., and Condit, R. (2012). Testing metabolic theory with models of tree growth that include light competition. Functional Ecology, 26(3), 759-765. doi: 10.1111/j.1365-2435.2012.01981.x
Stephenson, N. L., Das, A. J., Condit, R., Russo, S. E., Baker, P. J., et al. (2014). Rate of tree carbon accumulation increases continuously with tree size. Nature, 1476-4687. doi: 10.1038/nature12914