EXPLORING THE CARBON STOCK AND ITS POTENTIAL REGULATORS IN NAWABGONJ NATIONAL PARK (NNP) OF NORTHERN BANGLADESH

Abstract

Tropical forests are indispensable for the initiatives to counter biodiversity loss and play a significant role in sequestrating and storing atmospheric CO2 emissions. Sal forests of Bangladesh have greater potential in restoring biodiversity and enhancing carbon capture. However, the forest is under threat due to encroachment and over-exploitation; therefore, the present study was undertaken in Nawabgonj National Park (NNP) of northern Bangladesh to explore the carbon stock and its potential regulators. Forest inventory was carried out in 30 quadrants of 20m × 20m size. Data on structural, height, diameter at breast height (DBH), and soil parameters were collected within the quadrants. The collected soil samples were processed and analyzed for soil pH, moisture, soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), and total potash (TK). The results of this study revealed that the species richness of Sal is higher than the other species; the other species found were planted under an enrichment plantation program. The results of the Margalef index (0.4239) and Shannon-Wiener Index (0.20) indicated that Sal is a single-dominated plant in NNP. The average height of the trees of NNP ranged from 6.94 to 21.12 m with a mean of 11.84 m. The average DBH of the trees within the quadrant ranged from 16.19 to 75.76 cm with a mean of 44.99 cm. The highest number of trees lies in the height range of 1-5 m and the highest number of trees lies in the diameter range of 1-5cm; the number of large trees having height >25 m and having diameter >25 cm is very less. In this study, above-ground biomass (AGB) was 158.21 Mg ha-1 while the above-ground carbon (AGC) was 79.11 Mg ha-1. AGB and AGC were found to have a more strong relationship with soil properties than structural properties. In the case of soil's physical and chemical properties, the average percentage of soil moisture was found 19.54 %. The soil pH was acidic, with a mean of 4.98. The mean SOC of the study was 0.61% and NNP soil was 0.16 meq/100g SOC had a more strong relationship with structural components than the soil properties. Furthermore, both the structural and soil parameters significantly explained above and belowground SOC. Therefore, maintenance of structural and soil properties might assist in higher carbon stock and biodiversity of the Sal forest ecosystem.