Impact of Coal Mining on Vegetation: A Case Study in Jaintia Hills ...

IMPACT OF COAL MINING ON VEGETATION: A CASE STUDY IN JAINTIA HILLS DISTRICT OF MEGHALAYA, INDIA4.2.2. Basal CoverThe basal area (m 2 ha -1 ) in both mined and unmined areas showed no trend and were almost equallydistributed. Comparatively low basal area in spite <strong>of</strong> high population density (individuals ha -1 ) in theunmined site attributed that the trees dominated were <strong>of</strong> smaller in size (Figure 4.5). The higher basalarea in the mined areas though it had low density, could be attributed to the existence <strong>of</strong> bigger treesand causing no damage to these trees during mining operations by the miners. This indicates theremoval <strong>of</strong> younger trees during mining. Such a trend leads to the failure <strong>of</strong> the community to generateback naturally. Similar trend were also observed by Paijman (1970) in New Guinea, Newbery et al.(1992) in Malayasia and Parthasarathi and Karthikeyan (1997) in India for various disturbed foreststands.35Total basal area (m 2 ha -1 )302520151050Control Zone-I Zone-II Zone-III Zone-IVStudy sitesFigure 4.5: Basal area <strong>of</strong> tree species in control and mined areas.4.3. <strong>Impact</strong> <strong>of</strong> <strong>Coal</strong> <strong>Mining</strong> on Species Distribution PatternPlant populations exhibit three patterns <strong>of</strong> spatial distribution, viz., contagious or clumped, randomand regular or uniform. Patchiness, or the degree to which individuals are aggregated or dispersed, iscrucial to the understanding <strong>of</strong> how species uses resources, and how it is used as a resource. Besides,the distribution pattern <strong>of</strong> species population is <strong>of</strong>ten related to its productive biology. Webb et al.(1967), Ashton (1972) and Austin et al. (1972) indicated that in the absence <strong>of</strong> major disturbance, soiland water conditions play major roles in controlling species distribution pattern.In the unmined area most <strong>of</strong> the tree and shrub species showed contagious distribution pattern (85 and89%). In the mined areas all the component <strong>of</strong> the plant species represented contagious pattern <strong>of</strong>distribution (Table 4.5). The contagious distribution pattern <strong>of</strong> species indicated the mosaicness <strong>of</strong> theforest stand. The contagious <strong>of</strong> the species suggests the increase in fragmentation <strong>of</strong> the naturalvegetation due to mining. Similar species distribution pattern was observed by Sarma (2002) in coalmining areas <strong>of</strong> Nokrek biosphere reserve <strong>of</strong> Meghalaya.38