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Study of the tree community was carried out in the forest of Gandhamardan hills belonging to Eastern Ghats at Harishankar of Balangir district, Odisha, India in the year 2008 from January to December. Eighty quadrates of 20m×20m size were laid in the 100ha protected forest (N = 20o 51`027``, E = 82o 51` 59.2``) across eleven altitude ranges between 350m and 625m. A total of 42 species (39 genera & 25 families) were recorded in the present study. Species occurring at only single altitude range are Acacia lenticularisBuch.ham. Ex Benth. In Hook. Bombax ceibaL., Euphorbia nivulaBuch.-Ham., Holarrhena pubescens (Buch.-Ham.) wall.ex G.Don., Pongamia pinnata (L.)Pierre and Schrebera swietenioidesRoxb. Only one species i.e Anogeissus latifolia (Roxb.ex DC.) wall. Ex Guill. & Perr occur in all the eleven altitude ranges. Throughout all altitude ranges; 47, 75 and 101 species shows regular, random and contiguous distribution pattern. This reflects the contiguous distribution to be prevalent in the forest community. When random and contiguous distribution increase from lower altitude to mid altitude and again decrease from mid to higher altitudes, the reverse trend is observed in case of regular distribution. Total species and family occurrence increases from lower to mid altitude and again in decreases towards higher altitudes. Highest thirty five species occur in the mid altitude range of 400-425m while lowest seven species occur in the higher altitude of 575-600m respectively. Species occurring in all the altitude ranges have been ranked based on their IVI values and D-D (Dominance- Diversity) curves for each range have been drawn. The co-efficient of determination (R2) of the D-D curves show that the two highest value 0.924 and 0.895 fall in the altitude range of 425-450m and 450-475m. Hence tree species diversity can be best studied at altitude ranges of 425-450m and 450-475m. |
