Carbon balance of a primary tropical seasonal rain forest

Abstract

The role of primary tropical rain forests in the global carbon cycle is under active debate. By combining long‐term forest inventory data with physiological measurement data in a 1 ha permanent ecological research plot beneath an eddy covariance flux tower in a primary tropical seasonal rain forest, the ecosystem carbon balance was investigated and a detailed site‐specific carbon budget was established. The studied ecosystem was a carbon sink as determined by both eddy covariance (1.19 Mg C ha−1 yr−1) and biometric methods (3.59 Mg C ha−1 yr−1). Biometric‐ and eddy covariance‐based net ecosystem production showed no convergence in our investigation period. The large biomass increment, caused by the rapid annual growth rate of large trees, primarily accounted for the large ecosystem carbon sink derived from the biometric method. High leaf respiration in relation to carbon allocation and low ecosystem carbon use efficiency (0.34) were observed at our site.