Geospatial Approach for National Level TOF Assessment Using IRS High Resolution Imaging: Early Results

Abstract

Estimation of Trees Outside Forests (TOF), a valuable vegetation component in the overall constitution of land use/land cover as well as sustainable economy, poses a challenge in its estimation, due to its discrete nature of its spread and highly dynamic occurrence. The present study is a part of ‘Vegetation Carbon pools’, a sub project of National carbon Project, which aims to employ satellite remote sensing in tandem with in situ methods. Study is proposed to be taken up using geospatial framework. The spatial framework relies on the premise that trees outside forests are likely to occupy specific spatial contexts such as man-made infrastructure as part of various plantation programmes and it is possible to map such spatial context e.g., roads, railways, canal and ponds(referred as ‘TOF niche’) . A geospatial frame using a grid of 5 × 5 km resolution has been prepared involving information derived from a national zonation using multiple themes, open series digital topographic sheets and land use land cover database at 1:50,000 scale, available under Natural Resources Census of ISRO-National Natural Resources Management System. Gridded frame aims to stratify entire India in terms of density of infrastructure that may harbour TOF followed by selection of representative windows of high resolution panchromatic and multispectral Indian Remote Sensing images. A case study demonstrating the approach was carried out for the Telangana region. TOF information was derived using satellite images, available from open source Earth visualization, in specific sampled grids across sub-regions of Telangana to establish factors explaining each niche in terms of TOF content, which was used to derive estimates across the region intended. In all, 4005 grids were considered for assessment which contained 73,84,000 trees, which amounted to an average of 73.7 tree per sq km .