Reflecting on species diversity and regeneration dynamics of scientific forest management practices in Nepal

Implementation of sustainable forest management approaches, balancing mass timber production and intact ecosystem services through maintaining species diversity, has ever been the challenges for policy makers and practitioners in tropical forestry. Scientific forest management (SciFM) is a popular management approach that is increasingly adopted in Sal (Shorea robusta) dominated forests of Nepal, aiming to accelerate timber production and to improve forest condition. Being based on specific management plan, SciFM practices involve application of various silvicultural practices to manipulate forest composition and stand structure referring to the whole rotation period of a particular forest stand. Of the various aspects of SciFM, we aim to quantify the effect of SciFM on species diversity and regeneration dynamics, and compare diversity indices and regeneration attributes between managed and unmanaged forest stand in lowlands of Nepal, through establishment of permanent sample plots and its measurement in 2014 and 2018. Data collection about plant species and regeneration attributes was carried out in 50 sample plots of size 10 m x 10 m, established by stratified random sampling using quadrat method. Data analysis was done by using various diversity indices and compared through paired t-test. We also carried out correlation and regression analysis of diversity indices with predictor variables; such as canopy cover, number of individuals ha(-1), basal area ha(-1) and site productivity index. Our study found that plant diversity is significantly decreased but the concentration of dominance is significantly increased in managed forest blocks. Diversity indices were found to have a higher degree of relationship with number of individuals ha(-1) and canopy cover as compared to site productivity index and basal area ha(-1). Similarly, seedling density and sapling density is found to be increased in managed blocks, ensuring the production and productivity of forest stand sustainably. Based on our analysis, we argue that opening of canopy through regeneration felling is important in promoting regeneration establishment and growth but further research is needed to balance the species diversity along with the practice of intensive management interventions.