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Mapping of tree-clad area and assessment of Ecological status and bio-diversity outside forested area using Satellite data fusion and GIS Techniques

Mapping of tree-clad area and assessment of Ecological status and bio-diversity outside forested area using Satellite data fusion and GIS Techniques

Kln Sastry and Ravi Jadhav
Space Applications Centre (SAC)
Indian Space Research Organisation (ISRO)
Ahmedabad, gujarat state, india
Phone: +91-79-6774026 or 6774034 (O)
E-mail: [email protected], [email protected]

The forest cover of India, as per the present assessment, is 63.73 million ha constituting 19.39% of the geographic area, out of which 37.74 million ha (11.48%) is dense forest, 25.50 million ha (7.76%) open forest and 0.49 million ha (0.15%) mangroves. Madhya Pradesh accounts for the largest forest cover of the country i.e. 20.68% followed by Arunachal Pradesh (10.80%, Orissa (7.38%), Maharashtra (7.32%) and Andhra Pradesh (6.94%). The seven North-Eastern states together comprise 25.70% of the total forest cover. Comprehensive assessment of the forest resource involves measurement of numerous parameters such as forest cover, growing stock, annual increment, species composition, bio-diversity, non-timber forest products etc. However, in the absence of adequate resources, the Forest Survey of India is able to assess only the forest cover biennially, at the national level, using remote sensing technology. The assessment of other parameters is done only for the specific areas. Due to technological limitations of the remote sensing and paucity of resources, separate assessment of the forest plantations is not done by the Forest Survey of India (FSI). The actual area of existing plantations is, however, uncertain as some of the plantations do not survive and short rotation plantations get harvested. The details about species composition, location, ownership, age class is also uncertain in the absence of proper records. Forest and out side plantations constitute a very important part of the ecological status assessment of the area. A lot of wood produced in the country now comes from tree plantations established within or outside forest reserves.

Detailed and accurate knowledge of this resource by area, broken down to species and age classes, their locations, purpose and ownership are essentially required for rational planning

The total geographical Area of Gujarat State is 196,024 sq km while as per FSI survey carried out in 1999, the area covered under some or other type of forest is merely 12,965 sq kms, comprising only 6.61% of the total geographical area of the state. Thus, it is apparent that the forested area in the state is far less than the ecologically optimum 33.3% area, which should be under forests. Due to inadequate forest covered region, the state is facing the severe drought conditions on a persistent basis. To bring about the ecological equilibrium, large-scale tree-plantation has become the need of the day. Thus, mapping the tree-covered / tree-clad areas outside the forested region with a view that uncovered areas may be brought under the shadow of the tree. The study carried out by FSI will not give the account 93.39% of the geographical area. But, it is observed that, there is so much of land under tree cover along the roads, canals, Public parks and other lands. Each tree is essential for assessing the ecological status of the given area. Hence, it is felt that Tree – Clad area mapping is very important for the correct assessment of the area.

The main objective of the study is Mapping of the tree-clad area in GandhiNagar district of Gujarat State, India, at 1:12 500 scale using Satellite Data Fusion and GIS techniques. The entire GandhiNagar district comprising of 649 sq.km. The area is fully covered in Four scenes of the IRS-1C/1D LISS – III and 16 scenes of PAN corresponding to above LISS – III data.

Data used

  • 04 scenes of IRS 1C/1D LISS-III covering entire district and 16 PAN quadrants.
  • Survey of India topo-sheets showing district boundary.
  • Gujarat Forest Department maps for separating RF, PF & UF (Reserved, Protected & Unclassed) boundaries.

Mapping of tree-clad area and assessment of Ecological status and bio-diversity outside forested area using Satellite data fusion and GIS Techniques

Methodology
Survey of the forested region using the satellite data is not a new concept now. However, the present study is carried out by using the Fusion technique of Satellite data of two sensors. IRS 1C / 1D LISS-III having 23 meter resolution fused with the PAN data of 5.8 meter resolution. The LISS-III and PAN fused data brings out the product in 5.8 meter spatial resolution in multi-spectral mode facilitating an easy interpretation of vegetation, road / canal side plantation, riverian plantation etc. which are the prime objectives of the study. The district boundaries were digitized and the LISS-III and PAN merged data of IRS- 1C/1D were Geo-Referenced with district mask and digitally interpreted for mapping the tree-clad areas of the district. Thus, digitally classified image was imported into GIS to integrate with attribute data and further processing like Action plan Generation for potential areas for New Plantation, Area calculations, etc. Finally, ground verification was carried out for accuracy checking.

Finding

  • As pre the preliminary analysis carried out it is found that large part of the area is under tree cover.
  • Assessment of ecological status of the district based on tree cover out side forested areas
  • Accountability for the 93.39% of geographical area of the district.
  • Action plan for Potential areas for New Plantation in order to bring more areas under tree cover



Schematic Representation Tree clad Area Map