Biometric Estimation of Carbon Storage in &i&Hevea brasiliensis&/i& Planted in Different Densities

摘要

Carbon pool can be found in all four spheres of earth and the flux of carbon from one pool to another would result in climate change. An increased awareness to offset release of carbon in the atmosphere is emphasized in the United Nations Framework Convention on Climate Change through Kyoto Protocol. The establishment of rubber forest for the purpose of reducing atmospheric carbon is one of the options to sequ ester carbon in addition to benefitting from timber harvests at the end of crop rotation. The study analysed carbon concentration and carbon content in all plant parts of eleven-years-old rubber clones; RRIM 2020 and RRIM 2025 planted in four planting densities; 500, 1000, 1500 and 2000 plants/ha. Carbon concentration was found the highest in leaf of RRIM 2020 at 500 plants/ha density (53.3% 0.2%). This could be explained by the presence of photosynthetic activity and the resulted high amount of lignin. Carbon content is found the highest in large branch of RRIM 2020 at 500 plants/ha density (93.04 ± 11.22 kg), because of the high biomass weight of large branch and the abundant amount of lignocellulosic material. Trend analysis of total carbon sequestered in plant parts with planting density was found to be in negative pattern; quadratic and cubic regression for RRIM 2020 and RRIM 2025, respectively. However when total carbon content per hectare was calculated it was found that carbon content was the highest at 1500 plants/ha density (140.355 ± 9888 kg, clone RRIM 2025). Even though high density planting gave higher carbon sequestration per hectare, planting at 500 plants/ha is still recommended as this gives more biomass weight to rubber plant parts and thus subsequently benefits the timber industry.