Effect of altitudes and aspects on carbon sequestration potential of Quercus floribunda forests of Garhwal Himalayas

The forests are major resources for carbon sequestration and help to mitigate the adverse effect of atmospheric carbon and reduce global warming. The present study was conducted to estimate the carbon sequestration potential of the Quercus floribunda forests at two different aspects and three altitudes. Ten quadrates of 10 × 10 m size were laid out in each forest for the estimation of stand density, tree biomass, and soil samples were collected from each quadrate. Q. floribunda was the dominating tree at studied altitudes and aspects with the IVI values of 161.14 and 124.96 in the southern aspect and northern aspects, respectively. the highest values of above-ground biomass density (AGBD), below-ground biomass density (BGBD), total biomass density (TBD), and total carbon density (TCD) was recorded at the upper elevation (2500–2700 m) of southern and northern aspects. In the southern aspect values of AGBD (476.67 < 575.67 Mg/ha), BGBD (124.8 < 148.9 Mg/ha), TBD (601.53 < 724 Mg/ha), TCD (300.83 < 362.03 Mg/ha) were higher than northern aspect. The values of AGBD, BGBD, TBD, and TCD were reported maximum (638 Mg/ha, 163.1 Mg/ha, 800.5 Mg/ha, and 400.35 Mg/ha; respectively) in the upper elevation. Soil organic carbon (SOC), soil organic matter (SOM), and soil organic carbon stock (SOCS) decreased with increasing altitudes and depths which were found higher in the southern aspect. Bulk density (BD) and P increased with altitudes and depth however bulk density was equal (1.29 g cc^-1) in both aspects whereas P was also found higher (31.43 kg/ha) in the southern aspect. Highest available nitrogen (398 kg/ha) was recorded in the northern aspect at middle altitude. The available potassium was highest in the northern aspect. At lower altitudes, available potassium ranges between 246–615 kg/ha. Soil pH was found slightly acidic in all the sites ranging from 4.91 to 5.74 in different soil depths. Dehydrogenase activity was ranged between 1.35 and 8.74 µg/g/h from lower to upper soil depth and decreased with an increase in soil depths and increased with altitudes, whereas found highest in the southern aspect. The present study suggested that tree density, tree biomass, carbon sequestration potential, and soil health in Q. floribunda forests were substantially influenced by the altitude as well as the aspect. These findings contribute valuable insights for climate change mitigation and forest management strategies in the study region.