IMPACT OF COAL MINING ON VEGETATION: A CASE STUDY IN JAINTIA HILLS DISTRICT OF MEGHALAYA, INDIAFigure 3.4: IRS-1D LISS-III FCC for the period 2001.25
IMPACT OF COAL MINING ON VEGETATION: A CASE STUDY IN JAINTIA HILLS DISTRICT OF MEGHALAYA, INDIA3.3.3.1. Radiometric Correcti<strong>on</strong>First order correcti<strong>on</strong>s were d<strong>on</strong>e by dark pixel subtracti<strong>on</strong> technique followed by Lilles and Kiefer(1999).3.3.3.2. Visual Interpretati<strong>on</strong><strong>Study</strong><strong>in</strong>g changes <strong>in</strong> land use pattern us<strong>in</strong>g remotely sensed data is based <strong>on</strong> the comparis<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> thetime sequential data. Differences <strong>in</strong> surface phenomen<strong>on</strong> over time can be determ<strong>in</strong>ed and evaluatedby visual <strong>in</strong>terpretati<strong>on</strong> with local knowledge (Garg et al., 1988; SAC, 1999). For the present purposevisual <strong>in</strong>terpretati<strong>on</strong> technique was used for land use/ land cover mapp<strong>in</strong>g for four different yearsremote sens<strong>in</strong>g data <str<strong>on</strong>g>of</str<strong>on</strong>g> the study area.3.3.3.3. Change AnalysisThe land use/ land cover maps <str<strong>on</strong>g>of</str<strong>on</strong>g> 1975, 1987, 1999 and 2001 were c<strong>on</strong>verted <strong>in</strong>to grid format us<strong>in</strong>gIntergraph MGE Grid Analyst. Maps <str<strong>on</strong>g>of</str<strong>on</strong>g> different time periods were overlaid to f<strong>in</strong>d changes. The<strong>in</strong>crease or decrease <strong>in</strong> different land use/ land cover is obta<strong>in</strong>ed by <strong>in</strong>tersect<strong>in</strong>g and generat<strong>in</strong>g thematrices <str<strong>on</strong>g>of</str<strong>on</strong>g> change-no change for different years.3.3.3.4. Forest Fragmentati<strong>on</strong> AnalysisIt was measured by calculat<strong>in</strong>g the amount <str<strong>on</strong>g>of</str<strong>on</strong>g> forest patches occurr<strong>in</strong>g <strong>in</strong> a landscape with respect t<strong>on</strong><strong>on</strong>-forest patches. In the programme, Bio_CAP the area was reclassified <strong>in</strong>to three categories viz.,n<strong>on</strong>-forest, high fragmentati<strong>on</strong> and low fragmentati<strong>on</strong>.3.3.3.5. Phytosociological AnalysisThe community characteristics <str<strong>on</strong>g>of</str<strong>on</strong>g> vegetati<strong>on</strong> <strong>in</strong> coal m<strong>in</strong><strong>in</strong>g areas <str<strong>on</strong>g>of</str<strong>on</strong>g> Ja<strong>in</strong>tia <strong>Hills</strong> district <str<strong>on</strong>g>of</str<strong>on</strong>g> Meghalayawere studied dur<strong>in</strong>g the last week <str<strong>on</strong>g>of</str<strong>on</strong>g> October, 2004. To f<strong>in</strong>d out the impact <str<strong>on</strong>g>of</str<strong>on</strong>g> coal m<strong>in</strong><strong>in</strong>g <strong>on</strong>vegetati<strong>on</strong> distant gradient analysis was carried out. In this method, from the center <str<strong>on</strong>g>of</str<strong>on</strong>g> the study area,i.e., Lad Rymbai, structure and compositi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> vegetati<strong>on</strong> is observed <strong>in</strong> four different z<strong>on</strong>es. Theradius <str<strong>on</strong>g>of</str<strong>on</strong>g> the first circle i.e., z<strong>on</strong>e-I is 2 km. The distance from the periphery <str<strong>on</strong>g>of</str<strong>on</strong>g> the first circle to theperiphery <str<strong>on</strong>g>of</str<strong>on</strong>g> the sec<strong>on</strong>d circle is also 2 km and is c<strong>on</strong>sidered as z<strong>on</strong>e-II. Likewise, z<strong>on</strong>e-III and z<strong>on</strong>e-IV are del<strong>in</strong>eated (Figure 3.5). In each circle 24 sample plots each for tree, shrub and herbs were laid.Each sample plot was supported by 3 replicas. The total number <str<strong>on</strong>g>of</str<strong>on</strong>g> sample plots for tree, shrub andherbs came to 72 each <strong>in</strong> each z<strong>on</strong>e. The overall number <str<strong>on</strong>g>of</str<strong>on</strong>g> sample plots for tree, shrub and herbspecies was 288 each <strong>in</strong> the m<strong>in</strong><strong>in</strong>g areas, i.e., <strong>in</strong> all the four z<strong>on</strong>es. The vegetati<strong>on</strong> characteristics <str<strong>on</strong>g>of</str<strong>on</strong>g>the m<strong>in</strong>ed areas were compared with that <str<strong>on</strong>g>of</str<strong>on</strong>g> an adjacent undisturbed forest, i.e., Tubre Sacred Grove.The total number <str<strong>on</strong>g>of</str<strong>on</strong>g> quadrats laid <strong>in</strong> the c<strong>on</strong>trol site was 10.For tree comp<strong>on</strong>ent a quadrat <str<strong>on</strong>g>of</str<strong>on</strong>g> 10m x 10m size was laid while for the shrub species it was 5m x 5m.For the herbaceous species the size <str<strong>on</strong>g>of</str<strong>on</strong>g> the quadrat was 1m x 1m. The species found <strong>in</strong> the quadratswere identified with the help <str<strong>on</strong>g>of</str<strong>on</strong>g> the herbaria <str<strong>on</strong>g>of</str<strong>on</strong>g> Botany Department, North-Eastern Hill University,Shill<strong>on</strong>g and Botanical Survey <str<strong>on</strong>g>of</str<strong>on</strong>g> India, North-Eastern Circle, Shill<strong>on</strong>g. The plants hav<strong>in</strong>g CBH>15cm was c<strong>on</strong>sidered as tree, stem diameter 5-15cm at basal level was c<strong>on</strong>sidered as shrubs and stemdiameter