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

• Published in: Forests 2017-06, Vol.8 (6), p.209
• Main Authors: Liu, Chenggang, Pang, Jiaping, Jepsen, Martin, Lü, Xiaotao, Tang, Jianwei
• Format: Article
• Language: English
• Subjects: Age; Biomass; Carbon; Carbon dioxide; Carbon sequestration; chronosequence; Climate change; Forest ecosystems; Forests; Humidity; Laboratories; Land use; Latex; latex yield; Life expectancy; Life span; Net Primary Productivity; Organic carbon; Organic soils; Plantations; quadratic regression model; Raw materials; Regression analysis; Rubber; soil organic carbon; Soils; Terrestrial ecosystems; Topography; Trees; Tropical forests; Vegetation
• ISSN: 1999-4907; 1999-4907
• DOI: 10.3390/f8060209

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.