Tree Structure Analysis, Biomass and Carbon Stock of Sal Forests in Central Himalayan Region

Present study deals with density, species diversity, basal area, IVI, biomass and carbon stock in Sal forests. The study was conducted in three Sal forest sites around Champawat at Tanakpur. Among the fifteen tree species, total density of trees varied between 290-690 ind. ha-1 in all studied forest. The basal area of trees in forests was 50.92 to 78.84 m 2 ha -1 . Tree species diversity of Sal forests varied from 1.07-2.11. Biomass and carbon stock of trees ranged from 473.3 to 786.8 tha -1 and 224.8-373.7 tha -1 yr -1 respectively. Shorea robusta was dominated species based on density parameter in all studied forest sites. The tree density of Sal forests was slightly on lower side with comparison to natural forests in and around the region. However, density exhibits positive correlation at (p≤0.05) with biomass and carbon. But the difference in age and size of Sal trees showed the variation in biomass and carbon stock among the studied forest site. Present study concludes that Sal forests in and around nearby villages were in degraded conditions due to anthropogenic pressure. Thus, the forests must be conserved through judicious management by providing proper scientific inputs for high biomass and carbon.


Introduction
Forest plays a significant role in biomass production and carbon sequestration.Apart from these, they supply a wide range of goods and services including timber, fuelwood and fodder.Forests are foundation of biodiversity and also mitigate the climate change by sequestering carbon dioxide in atmosphere.
Present study of Sal (Shorea robusta Gaertn f.) forests covered a large area in foothills of Shiwalik in Kumaun region of Central Himalaya.Recent growing anthropogenic pressure on Sal forest for different uses like timber, fodder, fuelwood and leaflitter it is very imperative to assess the real time data about the stand structure, dry matter and carbon storage SIDDIQUI & LODHIYAL, Curr.World Environ., Vol.18(1) 107-115 (2023)   in such forest which are closed to human habitation.However, a few studies on sal forests particularly on biomass and Net Primary Production (NPP) were made by various researchers, [1][2][3][4][5] but there is scarcity of datarelated to carbon and its storage capacity in this region.] In this context, stand structure of Sal forest is very important in controlling the various aspects of dry weight, production and carbon potential growing in the region so that the sal forest could be managed and conserved for their full potential of biomass, productivity and carbon.This study aims to analyze the stand composition, biomass and carbon stock of Sal forest in Kumaun region of Central Himalaya.

Methodology Description of Study Site
This study was performed to evaluate the vegetation structure, biomass and carbon stock in sal forest sites located in Tanakpur (29.0748940N lat.and 80.10830180 E long) of Champawat district, Uttarakhand, India.The sal forest sites were located between 250-358 m elevation.On the basis of canopy cover sal forest sites were categorized into dense (Site-1), moderate (Site-2) and open forest (Site-3).The canopy cover of sal forest was 60-70% for dense forest, 50-55% for moderate forest and 25-40% for open forest.

Methods
Quadrat method (10 x10m size.) was used for the assessment of tree species.In each site, 30 quadrats were randomly placed and circumference of trees was considered at breast height i.e. 1.37 m from the ground level.In each study sites, vegetational parameters were estimated as followed. 8Species diversity of vegetation was evaluated by using Shannon-Weiner information index. 9Simpson Index 10 was used to calculate concentration of dominance (Cd).Biomass of tree components i.e. bole, branch, twig and leaves was estimated by using allometric equation developed by various scientists. 2,11Carbon was estimated by using the given factor. 7The carbon (C) was estimated by using biomass value of component of forest multiplied by 0.475 factor.In each site, total carbon of forest was anticipated by adding carbon values of all tree components.Statistical analysis i.e.Pearson's correlation test was performed using SPSS Software Version 21.0.

Site-3
Total carbon stock of trees was 224.8tC ha

Discussion
Forest structure, stocks of biomass and carbon varies with composition of tree species, age and density of plant species occurring in the forest.The tree species growing in Tarai region mainly dominated by Sal (S. robusta) and associated with trees and under canopy plant species.Present study was performed on structure, biomass and carbon content in respective forest site.The three forest sites were located at different area and direction.
Present findings had shown that there was a variation among various parameters studied in all forest sites.The site-1 had more tree density, diversity, biomass and carbon compared to other sal forest site-2 and site-3.On the basis of findings, it is concluded that the forests sites which had better management inputs and less extraction of usufructs had shown a good condition than the forest sites which had more anthropogenic pressure and poor management inputs as well as unscientific extraction of usufructs by nearby village.Apart from these, it is assumed that the existing soil and climatic condition of the area were also responsible for the vegetation structure and stocks of Sal forests of the region.Therefore, those forests which are degraded and have anthropogenic pressure should be conserved by providing better management and scientific inputs.So that these forests could save large amount of carbon by sequestering the atmospheric carbon continuously and would also help in the battle against global warming and climate change.

Fig. 1 :
Fig.1: Relationship between total biomass and carbon stock of Sal forests.

Table 3
).Total carbon stock ranged 373.9 to 224.8 t C ha-1 in the sal forests.The aboveground and belowground accounted 77.9 to 79.5 % and 20.5 to 22.1 % carbon respectively.