Forest Cover & Carbon Stock Change Measurements
Global climate is being affected by human activities that result from the emission of certain greenhouse gases (GHG) into the atmosphere. Carbon dioxide (CO2) in the atmosphere is a GHG that contributes considerably to global warming (IPCC, 1995). One possible strategy to reduce GHGs with great potential is to use forest to sequester CO2 (Prentice et al., 2000). Forests are relevant to climate change issues due to its function as a reservoir of carbon. Loss of forests is a significant contributing factor in climate change. On the other hand, the possibility of expanding carbon storage in forests has been identified as a potential measure to mitigate climate change (FAO, 2001, DeFries et al., 2000). Different percentages of forest cover store different amounts of carbon and the changes in forest cover, as expressed in a greenness factor to effectively surrogate biomass, are used in the model to calculate the annual changes of carbon (Houghton and Hackler, 2000; Myneni et al., 2001; Song and Woodcock, 2003).
Currently there is a tremendous amount and diversity being carried out related to forest and carbon accounting with a variety methods used for measurement. Remote sensing provides local/global estimates of carbon fluxes in forests. Remote sensing can fill in gaps where inventory information is unavailable. Remote sensing is most valuable applications in carrying out assessments of how climate change might be having an impact on forests by tracking major disturbances, changes in the growing season, and Net Primary Productivity (NPP). Carbon accounting is needed to support the objectives of international agreement to mitigate global climate change (UN, 1998). In conjunction with other spatial datasets such as climate, soil type, and tree height, the forest coverage is important in the carbon cycle model (DeFries et al., 2000).