Response of Woody Species to Anthropogenic Disturbances in Sacred Forests of Northeast India

摘要

The response of woody species to anthropogenic disturbances was studied in three forest stands viz., Swer, Nonglang and Nongkrem representing subtropical humid forests of the area. These forest stands were preserved till recently as sacred groves on the basis of religious beliefs. However, during the past decade, some portionsof these sacred groves have been disturbed due to product extraction following erosion in religious beliefs. The diversity and regeneration of woody species present in these forests has been studied to assess the response of the species to human disturbance. A total of 114 woody species (≥ 5cm dbh) were identified in the three forests. The species richness in disturbed stands was significantly lower in the disturbed stand (24-26) than the undisturbed stands (60-32). The density also followed a similar trend in Swer and Nonglang forest stands whereas, it increased from 898 stems ha'1 in the undisturbed stand to 954 stems ha~(-1) in the disturbed stand at Swer. The basal area of Woody species was significantly higher in the undisturbed stands (27 - 62 m~2 ha~(-1)) than the disturbed stands (3.14 - 58.25 m~2 ha~(-1)). The distribution of density in different dbh classes resulted in a reverse J-shaped curve in all the undisturbed stands, while in the disturbed stands, there was a reduction in density in the higher dbh classes. The densities of seedlings and saplings were significantly higher in the undisturbed stands than the disturbed stands, although seedling density far exceeded the sapling density in all the stands. The proportion of species showing no regeneration was high in the undisturbed stand as compared to the disturbed stand. Results revealed that species richness significantly got reduced, tree population structure showed a decrease in higher girth class individuals and the regeneration status of the species was also altered due to disturbance.