Smithsonian Global Forest Carbon Research Initiative: Quantifying and explaining variation in carbon pools and fluxes in tropical and temperate forests

Helene C. Muller-Landau, Smithsonian Tropical Research Institute, mullerh@si.edu (Presenting)
Benjamin L. Turner, Smithsonian Tropical Research Institute, turnerbl@si.edu
Markku Larjavaara, Smithsonian Tropical Research Institute, larjavaaram@si.edu
David King, Smithonian Tropical Research Institute, kingaz@yahoo.com
Shirley X. Dong, Harvard University, dong2@fas.harvard.edu
Sarayudh Bunyavejchewin, National Parks Wildlife and Plant Conservation Department, Thailand, sarayudh_b@yahoo.com
Nur Supardi, Forest Research Institute Malaysia, supardi@frim.gov.my
Stephen P. Hubbell, Smithsonian Tropical Research Institute, shubbell@eeb.ucla.edu

Because tropical and temperate forests together encompass an estimated 38% of terrestrial carbon pools and 48% of terrestrial net primary production, knowledge of their carbon budgets and of how these budgets respond to natural and anthropogenic global change is key to understanding the global carbon cycle today and in the future. Regrettably, there are still large gaps in our understanding of forest carbon pools, short- and long-term carbon fluxes, the mechanisms underlying these fluxes, and the likely impacts of global change – especially for tropical forests. The new CTFS Global Forest Carbon Research Initiative aims to fill these gaps through research quantifying the sizes of forest carbon pools and fluxes, their spatial and temporal variation, and the drivers of this variation at multiple tropical and temperate forest sites around the globe. CTFS has a 25-year history of forest dynamics research monitoring growth and mortality of >3 million trees of >8200 species (10% of the world’s tree diversity). Building on this work, we are now censusing carbon pools in soil, fine roots, coarse woody debris, and lianas as well as trees. We are measuring tree growth, tree mortality, litterfall, and soil respiration annually or subannually in order to estimate interannual variation in associated carbon fluxes. We will analyze the relationship of spatial and temporal variation in these carbon pools and fluxes to variation in climate and chemical drivers in order to test hypotheses regarding the effects of global change on forests, and develop a better basis for predicting future forest carbon budgets.