Monitoring India’s Forest Cover through Remote Sensing  Dr, J.K. Rawat IFS, Director, Forest Survey of India, Dehradun Tel: 0135 2756139, Fax: 0135 2759104 Email: fsidir@vsn.com  Dr. Alok Saxena IFS, Joint Director, Forest Survey of India, Dehradun Tel: 0135 2755037, Fax: 0135 2755037 Email: dr_aloksaxena@rediffmail.com  Sh. Sudhanshu Gupta Deputy Director, Forest Survey of India, Dehradun Tel: 0135 2755840, Fax: 0135 2759104 Email: sudhanshu64@rediffmail.com Forest Survey of India, Kaulagarh Road, P.O.:IPE, Dehradun – 248 195 1.1 Introduction Importance of Forests is globally recognized not only as important source of subsistence, employment, revenue earnings, raw materials to a number of industries but also for their vital role in ecological balance, environmental stability, biodiversity conservation, food security and sustainable development of a country. These have to be managed judiciously not only for environmental protection and other services but also for various products and industrial raw materials. Considering the crucial role forests play in the country’s ecological stability and economic development, the current National Forest Policy aims at maintaining a minimum of 33 percent of country’s geographical area under forest and tree cover. This requires periodic monitoring of the forest cover of the country for effective planning and sustainable development. There appears to be no efforts at National level prior to 1910 for mapping and monitoring of forests, though forest maps were available at local level mostly in the working plan documents of State Forest Departments. Even Survey of India carried out forest survey and mapping at scales decided by Superintendent of Survey with the forest departments. After 1910, forest surveys were made ancillary to topographical surveys. In 1976, National Atlas and Thematic Mapping Organisation (NATMO), a Government of India organisation, published Forest Atlas of India depicting administrative and forest boundaries. These maps, however, did not depict the actual forest cover in the country since all legal forest areas did not necessarily contain forest crop. Forest Survey of India (FSI), an organization under the Ministry of Environment & Forests (Government of India) was mandated in 1986 to monitor and map country’s forest cover on biennial basis. Consequently, FSI has been carrying out assessment of forest cover in the country using satellite based remote sensing data and has been publishing its findings in State of Forest Report (SFR) every two years. Remote Sensing technology has provided users the means to create numerous maps quickly and efficiently, subject to quality and resolution of data. Forest cover maps of the country, the States and Union Territories are prepared and used for carrying out several spatial studies, such as monitoring changes in forest cover, areas under shifting cultivation, assessment of forest density, status of wildlife habitats, forest fragmentation, forest fire affected areas, etc. In this paper, a brief account of such forest cover mapping by FSI is presented. 1.2 Remote Sensing Based Forest Mapping and Monitoring Application of satellite-based remote sensing in mapping, monitoring and management of natural resources has been recognized long ago. It was the National Remote Sensing Agency (NRSA) that in 1982 demonstrated that the space borne satellite data could conveniently do mapping of actual forest cover. Moreover, because of periodic availability of satellite data at short intervals of time, changes in the extent of forest cover at national and regional levels could be monitored in an unbiased and efficient manner. NRSA published two vegetation maps for the country using satellite data for the periods 1972-75 and 1980-82. Based on visual interpretation of false colour composites on 1:1 million scale for the two periods, NRSA study concluded that forest cover of the country reduced from 16.89% to 14.10% during the seven years. Although there were certain gaps in the quantitative assessments made by NRSA, the usefulness of satellite-based remote sensing technology in forest cover mapping was firmly established. Almost simultaneously, the Forest Survey of India (FSI), an organization under the Ministry of Environment and Forests, government of India, also developed the capacity to interpret and classify the satellite data for assessment and mapping of forest cover. FSI, a premier national forest resources survey organization in the country, was created with effect from June 1, 1981 as a successor to Pre-investment Survey of Forest Resources (PISFR) to furnish data through countrywide comprehensive forest resources survey at regular intervals. FSI used Landsat (MSS) imagery pertaining to the period 1981-83 for the first assessment of forest cover. The technique used for interpretation of satellite data was visual interpretation and scale of interpretation was 1:1 million. Interpretation was followed by extensive ground truthing. The forests were classified into dense forest (crown cover of more than 40%) and open forests (crown cover between 10-40%). Mangroves were delineated as a separate class. Degraded forests having crown cover of less than 10% were classified as scrub (a non-forest category). As per this assessment forest cover of the country was estimated to be 642,041 km˛ (19.52% of country’s geographic area).
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