Application of Remote Sensing in Detection of Forest Cover Changes Using Geo-Statistical Change Detection Matrices – A Case Study of Devanampatti Reserve Forest, Tamilnadu, India

The continuous observations on forest cover through the spaceborne technology known as remote sensing provide relative accuracy for temporal variation, changes and spatial distribution of forest biodiversity. The present study describes the temporal changes in forest cover and their spatial distribution in Devanampatti Reserved Forest in Tiruvannamalai District of Tamilnadu using change detection matrices technique by integrating remote sensing and GIS. Remote sensing technology provides satellite imagery with synaptic coverage on large area and high spatial resolution to identify individual species in biodiversity and delineating various forest types at national, regional and local level, and that facilitates to manage and conserve the forest biodiversity worldwide. The present study carried out using Landsat TM and ETM+ imageries acquired in 1977, 1991 and 2006 during the same seasonal period. The present study has brought the view of temporal variation of forest cover and its distribution in various periods. This also revealed the changes and spatial distribution of particular forest types into what types of spatial feature from the past period to present. The study showed rapid changes of forest cover between the two decades; the result of change detection analysis reveals that the deciduous forest cover spatially distributed to about 57.35 km² in 1977 and it tremendously decreased to 29.60 km² in 1991 and 23.56 km² in 2006. The decreasing rate per year between 1977 and 2006 was estimated at 0.65 %. The area of mixed forest cover was estimated to be about 35.30 km² in 1977, which decreased to 41.75 km² in 1991 and 18.96 km² in 2006 with the decreasing rate of 0.018% per year. Unfortunately, the rich forest biodiversity degraded into sandy gravel or eroded landform, and range of area cover was about 18.93 km² in 1977 and 24.30 km² in 2006 and rocky exposure increased in its area from 44.67 km² in 1977 to 77.79 km² in 2006. The changing rate of these landforms increased per year to about 0.11 % and 0.63 % respectively.