National Academy of Agricultural Sciences (NAAS)
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PRINT ISSN : 2319-7692
Online ISSN : 2319-7706 Issues : 12 per year Publisher : Excellent Publishers Email : editorijcmas@gmail.com / submit@ijcmas.com Editor-in-chief: Dr.M.Prakash Index Copernicus ICV 2018: 95.39 NAAS RATING 2020: 5.38 |
Changes of vegetation pattern of Dilli Reserve Forest under Sivasagar Forest Division, Assam has been studied owing to invasion of aggressive smothering vine Mikania micrantha during 2014-2017. Dipterocarpus retusus was the predominant element in the upper canopy layer of natural forest site which grown gregariously in well drained alluvial plains of the foothills of Patkai range having IVI of 13.19 followed by Mesua ferrea (10.76), Artocarpus chama (10.63) and Vatica lanceaefolia (8.77). In contrary, the Mikania infested forest areas top canopy strata was dominated by deciduous species of short leafless period viz. Ficus hispida (IVI 14.47), Lagerstroemia speciosa (IVI 12), Balakata baccata (11.49) etc. Tree density of infested site was recorded as 1276 /ha. and in un-infested natural forest sites it was 2380/ha. Highest tree basal area of natural forest indicated the dominance of more mature large trees of Dipterocarpus and Mesua. Seasonal fluctuation of M. micrantha revealed that the weed vigorously invaded in the surrounding forest edges and open canopy areas with highest population density (9.28 m2) in post monsoon season. It alone constituted 18.01 % of herb layer contained the regenerating tree seedlings and other herb species. Diversity index values were comparatively high in un-infested sites. Only 43.81% similarity was observed between un-infested and infested forest sites. Smothering effect of fast growing vine have severe impact in regeneration and seedling establishment of indigenous tree species mainly in periphery and open canopy areas. They triggered the deciduous species usually, which altered the forest scenario in near future.
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