The Economic Valuation of Oak Trees Decline Regions (Quercus brantii .Lindl) in Semi-Mediterranean Zagros Forests Using Sentinel-2 Satellite Imagery

This study used satellite imagery to evaluate the effect of oak trees’ decline on carbon storage and its economic value in Zagros forests of Kuhdasht, Lorestan Province, Iran. To this goal, the study used the Sentinel-2 Satellite MSI sensor data recorded on June 15, 2021. In order to measure the ground biomass, we randomly selected 250 square samples with dimensions of 30 × 30. The Diameter at Breast Height [DBH] of each tree was measured and the amount of ground biomass for each sample plot was also obtained. General multivariate regression, Artificial Neural Networks, and K-nearest neighbors were used for modeling the ground biomass of the selected regions. In order to value the amount of stored carbon, the average rate was used for each ton of absorbed carbon dioxide gas (54 euros). The plot for the monetary valuation of carbon (in terms of carbon dioxide absorption) was determined by using the relationship between the amount of ground biomass and stored carbon, as well as absorbed carbon dioxide gas. The results showed that linear regression obtained by the vegetation index of NDVI with R2=0.73 and RMSE (%) = 21.88 was the best model for the studied area. The findings confirm that Sentinel-2 imagery data were considerably efficient for estimating the ground biomass of the Zagros declined forests.  Moreover, the results of the economic valuation of the carbon inventory in terms of carbon dioxide absorption service showed that each hectare of forests in the region has a value equivalent to 2547.12 Million Rial in carbon dioxide absorption function. The economic valuation of declined areas indicated that the more the degradation [decline] of these areas escalates, the more their economic value decreases. Accordingly, the highest value was obtained in the healthy areas and the lowest amount was calculated in the most declined regions. The findings suggest that Sentinel satellite images could be used to determine the accurate biomass map for the degraded areas. This map can be employed as a base map for decision-making, forestation/protection operations, and the economic valuation of these invaluable resources.