The increase in the level of the atmospheric concentration of greenhouse gases has contributed to global warming which is the increase in temperature of the earth’s near-surface air and oceans(Ramachandran et al., 2008) and other associated impacts including sea ice melting and sea level rise during recent decades.
Carbon dioxide has become a major contributor to the greenhouse gas effect despite other greenhouse gases such as methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulfur hexafluoride (SF6). Thereby lowering the level of atmospheric carbon dioxide is set out as one of the essential global targets. The continued increase in its concentration in the atmosphere is believed to be accelerated by human activities such as the burning of fossil fuels and deforestation (IPCC, 2007). One of the major approaches for the lowering atmospheric carbon dioxide concentration is carbon (C) sequestration in the forests, a process of removing carbon from the atmosphere and depositing it in the trees.
According to the Kyoto Protocol (KP), carbon sequestration in terrestrial sinks can be used to offset greenhouse gas emissions. Forests have a higher Carbon density compared to other ecosystems types (Bolin et al., 2000). Forest ecosystems store more than 80% of all terrestrial aboveground carbon and more than 70% of all soil organic Carbon (Six et al., 2002a).
The amount of carbon dioxide sequestered in the forest ecosystem products is greater than the amount of carbon dioxide released through the decomposition and combustion of biomass (Flugsrud et al. 2001). The annual Carbon Dioxide exchange between forests and the atmosphere via photosynthesis and respiration is nearly 50 Pg C/yr. It is 7 times greater than the current anthropogenic carbon emission.
IPCC has been concluded that the cumulative amount of carbon that can be preserved and sequestrated during the period of 1995-2050 by lowering the deforestation and promoting reforestation in the tropics, associated with the implementation of a global forestation program is about 67-80 GTC(Browns et al., 1996).
Due to an unexpected population growth associated with economic development, intensifying deforestation and degradation of existing natural forest cover, arising demand for forest products as well as non-timber forest products including medicines and fuelwood and accelerated carbon dioxide emissions from anthropogenic sources have declined the global warming mitigating the potential of the forests. So the deforestation is needed to be lower and the reforestation has to be promoted.
According to the IPCC (2006), there are five carbon pools of a terrestrial ecosystem involving biomass including above-ground biomass, below-ground biomass, and the dead mass of litter, woody debris, and soil organic matter.
The above-ground biomass of a tree constitutes the major portion of the carbon pool. It is the most important and visible carbon pool of the terrestrial forest ecosystem. Any land use change like forest degradation and deforestation has a direct impact on this component of the carbon pool. The below-ground biomass which is comprised of all the live roots plays an important role in the carbon cycle by transferring and storing carbon in the soil. Both the above and belowground components of terrestrial ecosystems have sequestered 20–25 % of the carbon globally from fossil fuel combustion and cement production between 2000 and 2008 (IGBP/GCP 2010).
Soil organic matter is also a chief contributor to the carbon stocks of forests, next only to the above-ground biomass and soils are a major source of carbon emissions following deforestation. The dead mass of litter and woody debris are not a major carbon pool as they contribute merely a small fraction to the carbon stocks of forests
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