Forest Carbon

By: R Moharaj
Forests are one of the most significant reservoirs of carbon. Various global processes and anthropogenic changes are influencing the process of carbon sequestration leading to interruptions in the carbon flux. Under elevated CO2 conditions a possibility of decomposition occurring more than net primary production leading to a loss of carbon is predicted in the forest regions of India.

Forest ecosystems play a crucial role in global carbon cycling acting as a sink and a source. Forests form an active carbon pool that accounts for 60 per cent of carbon storage in the earth’s land surface. Therefore, dynamics of carbon in forest vegetation and soils are significant in terms of global climate change policy framework. The rate of carbon absorption is greatest in the earliest stages of growth and regeneration, and declines as forests mature. Tropical forests, both moist and dry types, accounting for approximately 60 per cent of global forests, dominate the role of forests in the global carbon flux and carbon stocks, and therefore require researchers and policy makers to estimate the carbon sequestration potentials. While covering only 22 per cent of potential vegetation by area, tropical forests have been estimated to account for 75 per cent of the world’s terrestrial net primary productivity. However, under elevated carbon dioxide (CO2 ) conditions a possibility of decomposition occurring more than net primary production (NPP) leading to a loss of carbon is predicted in some forest regions. In others, elevated CO2 and nitrogen deposition tend to increase NPP more than decomposition, leading to carbon storage. Given such an uncertain scenario, a micro level carbon flux examination of different forest types alone can give a clear picture. The two significant drivers of forest carbon flux are biophysical processes operating at various spatial and temporal scales and the local anthropogenic disturbances. In addition to this, global climate change and other multiple stressors such as ozone, sulphur and nitrogen depositions also influence the productivity and carbon stock, which has been largely ignored in the Indian scenario. Although many studies in the country have pointed towards forest degradation and productivity loss due to regional climate anomalies, fires, cultivation, mining, biomass extraction and cattle grazing, a cohesive outlay of forest carbon stock is the need of the hour. The challenge for the scientific and policy making community now lies in identifying the major factor that affects the carbon flux at the micro level.

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