Assessment and Monitoring of Deforestation from 1930 to 2011 in Andhra Pradesh, India Using Remote Sensing and Collateral Data

Deforestation is one of the greatest threats to the world's forest ecosystems. The present study has utilized remote sensing and GIS techniques to quantify changes in forest cover and to map patterns of deforestation in Andhra Pradesh, India during 1930-2011. Andhra Pradesh has the second largest recorded forest area and ranks sixth with an actual forest cover amongst all Indian states. Forest cover maps from seven temporal datasets were prepared based on interpretation of multi-source topographical maps and satellite data. A representative set of landscape indices has been used to study landscape-level changes over time. The mapping for the period of 1930, 1960, 1975, 1985, 1995, 2005 and 2011 indicates that the forest cover accounts for 85,392, 68,063, 46,940, 45,520, 44,409, 43,577 and 43,523 sq. km of the study area respectively. The study found the net forest cover declined as 49% of the total forest area during the last eight decades. The annual rate of estimated deforestation during 2005-2011 was 0.02%. Annual rate of deforestation of teak mixed forests was relatively higher (0.76) followed by mangroves (0.58%), semi-evergreen forests (0.43%), dry deciduous forests (0.21%), moist deciduous forests (0.09%) and dry evergreen forests (0.07%) during 1975-2011. The landscape analysis shows that the number of forest patches was 3,981 in 1930, 5,553 in 1960, 8,760 in 1975, 9,412 in 1985, 9,646 in 1995 and 10,597 in 2011, which indicates ongoing anthropogenic pressure on the forests. The mean patch size (sq. km) of forest decreased from 21.5 in 1930 to 12.3 in 1960 and reached 3.9 by 2011. The analysis of historical forest cover changes provides a basis for management effectiveness and future research on various components of biodiversity, climate change and accounting of carbon.