ASSESSING THE EFFECT OF TREE CANOPY OPENING IN THE REGENERATION LAYER OF TERAI SAL (SHOREA ROBUSTA) FOREST (A Case Study from Buddhashanti Collaborative Forest of Nawalparasi District)

Abstract

The effect of tree canopy opening in the regeneration layer of Sal (Shorea robusta) were investigated in four strata of forest viz. 0-25, 25-50, 50-75 and 75-100 percentage crown cover vegetation in Shorea robusta forests in Nawalparasi. Regeneration survey was carried in two blocks each of 10 hector, where one block was silviculturally operated with irregular shelter-wood system and another was undisturbed. The seedling density of Sal (shorea robusta,) is higher in the 0-25 and 25-50 percentage crown cover than others two strata. Likewise, sapling density was also higher in the 0-25 and 25-50 percentage crown cover than dense strata. The Simpson index, Shannon diversity index, and Shannon's Evenness, of the seedlings were increasing with increase in crown cover percentage which indicate less diversity in open crown cover due to dominance of sal regeneration. Crown cover percentage was found negatively correlated with regeneration stock per hectare. The study shows that, open strata maintain seedling density, favor regeneration of Sal forests and regeneration of Sal dependent to the intensity of light and suitable condition for germination. Opening of crown directly provide sunlight on land surface which helps in germination of Sal.