Mitigating climate change and global warming through carbon sequestration by tree ecosystems is of prime importance since they are cost-effective, environmentally friendly and ecologically sustainable. Urbanization is a part of development, and rubber plantations are usually removed for this purpose, especially in Kerala, the southern state of India. Besides latex, the economic produce, and the associated income, the rubber tree is a fairly good sink for carbon in its biomass, with an average carbon content of 42 per cent and substantial carbon stock in the soil. In the present study, an account of total carbon loss by the removal of rubber plantation for urbanization and developmental activities are given. The present popular clone (RRII 105) existing in major share (85%) of the total rubber cultivation in India accounts for carbon sink loss 57 t ha-1, 57.5 t ha-1, 43.2 t ha-1 for 23 years and 148 t ha-1, 75 t ha-1 and 62.1 t ha-1 for 30 years from biomass, litterfall and sheet rubber respectively. The recent clones RRII 414, RRII 429 and RRII 417 have higher growth rates and higher biomass (44-50 per cent) carbon sink loss compared to the existing popular clone RRII 105. The carbon sink loss in the form of stored carbon in soil is 56.5, with a soil carbon content between 1.2 to 2 per cent. Due to the growth variation in diverse environments with extreme climatic conditions, the clones recorded differences in carbon stock and carbon sink loss. The central region of Kerala showed a higher loss, and a lower loss was in the drought-affected northern region than the southern region. The total carbon sink losses for 23 and 30 years were 214.2 and 341.5 t ha-1, respectively. This study points out that the serious carbon sink loss due to the removal of rubber plantations results in disturbing the self-sustained, carbon-friendly and economically sound perennial rubber ecosystem. Vegetation having higher C-sequestration potential and trees with higher lignin content is essential to increase carbon capture for mitigating the impact of the removal of plantations. From the present study, it is clear that the removal of rubber plantations is affecting the carbon sink loss, thereby the CO2 mitigating capacity, and is a serious matter of concern.

Mitigating climate change and global warming through carbon sequestration of tree ecosystem is of prime importance due to cost effective, environment friendly and ecological sustainability. Urbanization is a part of development and generally rubber plantations were usually removed for this purpose especially in Kerala, the southern state of India. Besides commercially high yield of latex, the economic produce of rubber plant and the associated income, rubber tree is fairly good sink for carbon in its biomass with an average carbon content of 42 per cent and substantial carbon stock in soil. This study pointed out the serious carbon sink loss from the removal of rubber plantation for urbanization, one of the major development activities which resulted in the damage of the self-sustained carbon friendly and economically sound perennial rubber ecosystem. The present popular clone (RRII 105) existing in major share (85 %) of the total rubber cultivation in India accounts carbon sink loss 57t/ha, 57.5t/ha, 43.2t/ha for 23 years and 148t/ha, 75t/ha and 62.1t/ha for 30 years from biomass, litter fall and sheet rubber respectively. The establishing modern clones RRII 414, RRII 429 and RRII 417 having higher growth rate and biomass recorded still higher (44–50 per cent) carbon sink loss compared to the existing popular clone RRII 105. The carbon sink loss in the form of stored carbon in soil is 56.5 with soil carbon content between 1.2 to 2 per cent. Due to the growth variation in extreme climatic conditions, the clones recorded differences in carbon stock and thereby carbon sink loss. The central region of Kerala showed higher loss and lower loss was in the drought affected northern region than South region. The total carbon sink loss for 23, 30 years were 214.2 and 341.5 t/ha respectively. Maintenance of green spaces/areas including vegetation having higher C-sequestration potential and trees having higher lignin content to increase carbon capture for mitigating the impact of removal of plantations especially in high altitude to some extent in the scenario of inevitable developmental activities and urban developments to become environment friendly. From the study it was clear that the removal of rubber plantation affecting the carbon sink loss greatly and thereby the CO2 mitigating capacity and is a serious matter of concern.

Natural rubber (Hevea brasiliensis Wild. Ex A. Juss.) Müell. Arg. is an important commodity crop grown in world over for industrial raw material rubber latex for various products, mainly tyre manufacturing. Hevea propagation is through clones evolved by breeding as cultivars with desired characters. This article presented the biomass and nutrient accumulation of four important Hevea clones viz. RRII 105, RRII 118, RRII 203 and GT1 at 30 years age. Biomass and nutrient concentration of tree components viz. trunk, branches, leaf and root were assessed by uprooting the trees in the field and standing trees using allometric equation. Among the different clones, RRII 118 and GT1 recorded higher biomass compared to RRII 105 and RRII 203. Above-ground biomass (88-93 per cent) varied more than below-ground biomass (7-11 per cent). The high yielding clones had higher leaf and root biomass. Drought tolerant and timber clones viz. RRII 118 and RRII 203 recorded higher K and high yielding clone RRII 105 had higher Ca accumulation. Biomass removal of these clones may lead to deficiency of K and Ca in soil and hence needs the external supplements. The relation of high Ca content and leaf disease of fungal origin is promising for further studies. The higher accumulation of iron and manganese indicated the tolerance of Hevea to these elements and possibility of phytoremediation. The per cent contribution of nutrients to total biomass varied less between clones and was below 3 percent at the age of 30 years and this is evidence of adjustments in proportions of nutrients in Hevea irrespective of clonal variations.