IMPACT OF CANE PLANTATION ON THE REGENERATION OF SAL (Shorea robusta) FOREST: A CASE STUDY OF DINAJPUR SAL FOREST

Abstract

Sal (Shorea robusta) is an important timber species which is found in the natural Sal forest of Bangladesh. The tropical moist deciduous Sal forest ecosystem of Dinajpur is currently in a critical situation. Destructive anthropogenic and natural impacts coupled with overexploitation of forest resources have caused severe damage to the forest ecosystem. In recent years the problem has assumed serious magnitudes. To protect Sal forest, cane plantation was done in 20 ha. area during 2013-2014 session in Nawabganj Sal forest and also done in some areas of the Singra Sal forest under the management of forest department. Though the program seemed to be successful, but it was not suitable for natural regeneration of Sal tree due to the bushy nature of cane plantation. The present study was an attempt to identify the current status of cane plantation in the Sal forest of Dinajpur and to explore the impact of cane plantation on the regeneration of Sal forest. The study was conducted in the Sal forest of Dinajpur district at two different locations namely Birganj and Nawabganj upazila during September 2018 to November 2019. Ten quadrates were selected randomly inside each Sal forest for this study. Five quadrates were Sal with cane species and five quadrates were only Sal species without cane species. Altogether twenty quadrates were selected in two Sal forest. The size of each quadrate was 20m×20m. Number of big Sal trees greater than 3 feet height, number of Sal seedlings below 3 feet height, number of Sal coppice seedlings below 3 feet height, number of Cane bush, number of germinated seedlings of Sal, number of Sal seeds per sq. m, height of Sal trees, diameter at breast height (DBH) of Sal trees, weight of leaf litter per sq. m etc. were measured from the sample plots (20m×20m). The overall results of the study revealed that all the parameters decreased due to cane plantation in the natural Sal forest which was responsible for poor regeneration of Sal seeds for the bushy structure of cane. Such as the average number of Sal trees (2022 and 1240) and average volume of Sal trees (40882 cft and 36351 cft) found per ha in only Sal and Sal with cane plantation in Dinajpur Sal forest. For better management of Sal forest cane plantation at the floor of forest should be restricted immediately.