In the Xishuangbanna tropical rainforest, both long-term catchment water observations and direct eddy covariance estimates indicate that more water underwent evapotranspiration in the rubber plantations than in the rainforest. However, little knowledge or observational data on carbon fluxes has been available so far.
Prof. ZHANG Yiping and his team of XIshuangbanna Tropical Botanical Garden (XTBG) used a biometric method to estimate the net dry matter production and net ecosystem production in a rubber forest, the most widespread plantation type in tropical Southeast Asia. The study site is located in the experimental area of the Xishuangbanna Tropical Botanical Garden (21° 55’ 30” N, 101° 15’ 59” E; size ~ 20 ha; elevation 570 m a.s.l.), Xishuangbanna, Yunnan Province, south-western China.
They assessed the carbon budget of a 33-year-old rubber plantation in tropical China. Specifically, this study was designed to determine: (1) if adult tropical rubber plantations are carbon sinks or sources; (2) whether eddy covariance and biometric estimates converge in a monoculture forest; and (3) if rubber plantations are a potential carbon sink when compared to primary tropical rainforest.
According to the biometric estimates and the eddy-flux net ecosystem CO2 exchange (NEE) derived with FluxNet procedure, the ecosystem studied was an important carbon sink, while the neutral atmospheric condition method provided a significantly lower NEE. Overall, when considering the whole life cycle, including deforestation of the prior-existing tropical forest, the hypothesis of plantations serving as large carbon sinks is not supported by their study.
The study entitled “Do the rubber plantations in tropical China act as large carbon sinks?” has been published in iForest – Biogeosciences and Forestry.
