Transition from forest to rubber (Hevea brasiliensis Muell. Arg.) plantation has occurred in tropical China for decades. Rubber has been planted on 1 million ha to provide raw materials to the rubber industry. The role of various-aged rubber plantations in carbon (C) sequestration remains unclear. The biomass C accumulation including latex C and C distribution in soil of five different-aged stands (7, 13, 19, 25 and 47 years old) were examined. The total biomass C stock (TBC) and total net primary productivity (NPPtotal), whether with or without latex C, had a close quadratic relationship with stand age. Regardless of stand age, around 68% of the C was stored in aboveground biomass, and NPPlatex contributed to approximately 18% of C sequestration. Soil organic carbon stock in the 100-cm depth remained relatively stable, but it lost about 16.8 Mg ha−1 with stand age. The total ecosystem C stock (TEC) across stands averaged 159.6, 174.4, 229.6, 238.1 and 291.9 Mg ha−1, respectively, of which more than 45% was stored in the soil. However, biomass would become the major C sink rather than soil over a maximal rubber life expectancy. Regression analysis showed that TEC for rubber plantation at 22 years is comparable to a baseline of 230.4 Mg ha−1 for tropical forest in China, and would reach the maximum value at around 54 years. Therefore, rubber plantation can be considered as alternative land use without affecting net forest ecosystem C storage. In addition to the potential C gains, a full set of ecosystem and economic properties have to be quantified in order to assess the trade-offs associated with forest-to-rubber transition.

https://www.mdpi.com/1999-4907/8/6/209/pdf

Carbon Stocks across a Fifty Year Chronosequence of Rubber Plantations in Tropical China

Temporal Changes of Ecosystem Carbon Stocks in Rubber Plantations in Xishuangbanna, Southwest China

The carbon storage in the rubber forest ecological system is mainly made up of the soil,undergrowth vegetation,litter and tree layers.Samples from the soil layer(0 cm-20 cm,20 cm-40 cm,40 cm-60 cm,60 cm-80 cm,80 cm-100 cm),undergrowth vegetation layer,litter layer and tree(5,10,15,20,25 and 30 years old) layer of the rubber plantation in Danzhou of Hainan were investigated,and the organic carbon of samples were indoor tested and analyzed.It was preliminarily concluded that the carbon storage of rubber forest ecological system in Danzhou of Hainan was 851.3 t/hm2.The carbon storage of soil layer was 536.9 t/hm2 the carbon storage of tree layer(306.8 t/hm2)the carbon storage of litter layer(4.4 t/hm2) the carbon storage of undergrowth vegetation layer(3.2 t/hm2).The carbon storages in the rubber plantations of different tree ages changed approximately between 75.7 t/hm2 and 152.7 t/hm2,and showed an approximately double peak trend.

Wang Xu

Papers

Carbon Storage and Distribution Law of the Rubber Forest Ecological System in Danzhou of Hainan