Sudhansu Sekhar Dash
Botanical Survey of India

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Journal : Indonesian Journal of Forestry Research

COMMUNITY STRUCTURE AND REGENERATION STATUS OF TREE SPECIES IN KYONGNOSLA ALPINE SANCTUARY, EASTERN HIMALAYA, INDIA Subhajit Lahiri; Sudhansu Sekhar Dash
Indonesian Journal of Forestry Research Vol 8, No 2 (2021): Indonesian Journal of Forestry Research
Publisher : Secretariat of Agency for Standardization of Environment and Forestry Instruments

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20886/ijfr.2021.8.2.241-257

Abstract

Habitat destruction, over exploitation, monoculture are major reasons for loss of primary forests in Himalaya. Tree population, composition and diversity particularly in the temperate Himalaya play a key role in the maintenance of many ecosystem services and natural biogeochemical cycles. The present study explores composition and regeneration status of tree species in a temperate mixed forest in Kyongnosla Alpine Sanctuary, East Sikkim, India.  Two sites at an elevation range of 2800–3800 m were selected and 20 plots of 20 m × 20 m for trees, 80 plots of 5 m × 5 m for saplings, and 160 plots of 1 m × 1 m for seedlings were sampled to study the regeneration status. A total of 17 tree species belonging to 9 genera and 8 families were recorded of which Rhododendron was the most dominant genus with maximum number of species. All the phytosociological attributes, such as relative density, abundance and important value index were calculated. The average species richness of adult trees and saplings was 13.5± 0.7 and for seedlings it was 12.5 ± 0.07. The mean density of seedlings was 3609.77 ± 494.39 individuals/ ha, for saplings  1540 ± 113.13 individuals/ha and of mature trees  548.75 ± 8.83 individuals/ha. Total basal area cover ranged from 36.61 to 40.35 m2/ha for trees, from 1.54 to 1.71 m2/ha for saplings.  Fair regeneration was observed in 64.72% of total species; good regeneration observed in 17.64% species, 11.76 % species exhibited poor regeneration while 5.88% showed no regeneration.  Density-diameter distribution exhibited decrease in tree densities towards higher DBH classes. The study not only provides reliable information on the ecosystem’s health of the sanctuary but also will help in understanding the complexity of the ecosystem function and an approach to conservation of biota.
A COMPREHENSIVE INVENTORY AND ECOLOGICAL ASSESSMENT OF ALIEN PLANT INVASION IN MIZORAM, INDIA Rabishankar Sengupta; Sudhansu Sekhar Dash
Indonesian Journal of Forestry Research Vol 7, No 2 (2020): Indonesian Journal of Forestry Research
Publisher : Secretariat of Agency for Standardization of Environment and Forestry Instruments

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20886/ijfr.2020.7.2.135-154

Abstract

Invasion by alien plants has a detrimental effect on the natural forest plant community, leading to the loss of native species. An inventory of alien plants facilitates in determining the potential threats to the natural plant biodiversity. This present paper evaluates the alien plants in Mizoram (an Indo-Burma hotspot region) and provides the first authentic inventory of alien plants of Mizoram along with their diversity, ecological aspects, origin, and status of invasion. Extensive field surveys were done during July 2018 to September 2019 in different protected areas of Mizoram.  We adopted Random Sampling Technique using nested quadrats in a plot size of 400 m2 (20 m × 20 m), within which a quadrate size of 5 m × 5 m was laid for shrubs and 1 m × 1 m was laid for herbs. Plant specimens were collected, dried, poisoned with 0.1% Mercuric Chloride (MgCl2); voucher specimens were prepared and deposited in Central National Herbarium, Botanical Survey of India (CAL) after proper identification.The results revealed the occurrence of 163 alien plant species under 135 genera belonging to 51 families in Mizoram.  Maximum species were represented by family Asteraceae with 29 species followed by Leguminosae (19 species), Convolvulaceae (9 species), Euphorbiaceae (7 species) and Amaranthaceae (7 species). The 57.66% of the alien species reported from Mizoram were of American origin followed by 11.65 % from African, 7.36% from Mexican and 5.52% from Australian origin. Life form analysis revealed the presence of 58.64 % herbs, 15.43 % trees and 9.87% shrubs. Out of the whole alien plants recorded, 91 species used in traditional medicines, 43 species as ornamental, 15 species were edibles, nine species used as timber and four species used as green manure. The study also recommends the ten most obnoxious species, five neo-invasive plants, which have the greatest potential threats to the native flora. The process and probable causes of invasion in the state were also discussed briefly, which may be utilized in the preparation of conservation or forest management policies.