Carbon balance of a primary tropical seasonal rain forest

Abstract

[1] 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.

Vulnerability of tropical forest ecosystems and forest dependent communities to droughts

“…Also, the reduction in the amount of NPP produced due to a drought estimated by this study, i.e., 4.3 -9.1 Mg ha -1 yr -1 of unavailable NPP (Table 4), are comparable to values reported by other studies (e.g., Tan et al 2010). In fact for a seasonal dry tropical forest in China, Tan et al (2010) reported a 38% reduction in NPP (i.e., 4.5 Mg biomass carbon ha -1 yr -1 lost) due to a drought.…”

“…In fact for a seasonal dry tropical forest in China, Tan et al (2010) reported a 38% reduction in NPP (i.e., 4.5 Mg biomass carbon ha -1 yr -1 lost) due to a drought. Fisher et al (2007) reported a similar reduction in gross primary production when they experimentally tested the response of an Amazonian rain forest to induced drought stress using a throughfall exclusion experiment.…”

Net primary productivity, allocation pattern and carbon use efficiency in an apple orchard assessed by integrating eddy covariance, biometric and continuous soil chamber measurements

“…About 46 % of annual NPP feeds the detritus cycle, and this is similar to natural forests if tree mortality is not considered (e.g., Tan et al, 2011), giving ample potential for the soil of the fruit tree ecosystem to act as a net carbon sink. The amount of NPP that increases the standing biomass, contributing to ecosystem C storage function (5 % of total NPP), is conversely much lower than in forests.…”

Spatial heterogeneity of soil respiration in a seasonal rainforest with complex terrain

“…The climate is dominated by the Indian monsoon cycle. The mean annual air temperature is 21.8 °C, and the total annual rainfall is 1493 mm, approximately 87% of which occurs during the rainy season (May to October - Tan et al 2010).…”