Above ground biomass and carbon stock estimation from Prosopis Juliflora in Banni grassland using satellite and ancillary data

Banni grassland (latitude-23°19′N to 23°52′N and longitude-68°56′E to 70°32′E) lies in the arid region located in Gujarat, India. It was once Asia's 2nd largest tropical grassland with an approximate area of 2610 Km². Prosopis Juliflora was introduced in Banni in select areas in 1960s to control salinity ingress and maintain green cover in the area. The ability of Prosopis Juliflora to withstand adverse arid and semi-arid conditions and produce woods of high calorific values (4200 kcal/kg) brought in proposals for biomass energy generation. This papers aims to estimate the biomass productivity from Prosopis Juliflora and assess the carbon stock in its wood. Land cover analysis with an accuracy of 94.4% was done using Landsat 5 TM 2011 satellite data to map the spatial distribution of Prosopis Juliflora and grassland. Analysis shows that Prosopis has invaded around 50% of the total area while the grassland area is found to be around 25-30%. Field studies were undertaken for tree sampling in 4 plots of size 50m×50m. Harvesting method was followed and vegetation parameters; DBH, Girth, no. of stem and tree height were measured along with sun dried weight of woody biomass. Allometric relationship was established between field data using regression analysis. Results show that biomass is linearly related (R²= 0.92-0.97) to vegetation parameters. Biomass productivity per hectare was found and total biomass productivity in Banni was deduced using area estimates from land cover map of 2011. Biomass estimate was converted into carbon stock was estimated by using a conversion coefficient of 0.47 as suggested by Wangda in the year 2012.