Tree Species Diversity and Community Structure across Forest Stands of Orang National Park, Assam
DOI:
https://doi.org/10.55863/ijees.2026.0985Keywords:
Orang Tiger Reserve, Forest stands, Tree diversity, Quantitative parametersAbstract
The present study was conducted in the Orang National Park (ONP), which is the core area of Orang Tiger Reserve (OTR), Assam. Different category of forest, i.e., Eastern Himalayan Moist Mixed Deciduous Forest (EHMMDF) dense forest, Eastern Himalayan Moist Mixed Deciduous Forest (EHMMDF), Open forest, and swampy Forest (SF) were sampled for detailed investigation of tree species diversity using quadrat method. A total of 45 tree species were recorded from 38 genera and 24 families. There were 39 species belonging to 34 genera and 23 families in the dense forest, whereas 33 species belonging to 29 genera and 20 families were in the open forest, and 17 species belonging to 15 genera and 11 families were recorded in the swampy forest stand. Margalef’s species richness index was found to be highest in dense (5.440) and open (5.359) forests and lowest in swampy forest stand (2.312). Based on the Importance Value Index, Bombax ceiba is the dominant species in both the dense forest stand and the open forest stand. In the swampy forest stands Trewia nudiflora, had highest IVI value exhibiting a dominant species. The Shannon-Weiner diversity index (H´) was computed highest (3.198) in the open forest, followed by the dense forest stand (2.845) and swampy forest stand (2.328). On the other side, the Simpson’s index of dominance (D) was found to be 0.047, 0.087, and 0.12 in the dense, open, and swampy forest stands, respectively. The Pielou’s evenness index (J´) was computed as 0.777, 0.915 and 0.822 for the dense, open, and swampy forest stands, respectively. The highest similarity was recorded between dense and open forest (80.55%), followed by dense and swampy (53.57%), and lowest was recorded between open and swampy forest stand (40.8%). The findings from this study provide valuable insights into tree species diversity and the status of the forest which will be helpful for forest biodiversity conservation. Additionally, they can contribute to enhancing future management strategies.
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