Carbon stock assessment in various ecosystems is vital for monitoring the health of these ecosystems and national accounting for the United Nations convention on climate change. The influence of various anthropogenic drivers on carbon stock in different ecosystems has not been examined comprehensively. This study aims to determine the impact of anthropogenic pressures (lopping, cutting, grazing) on soil physico-chemical properties and carbon stock in four temperate broadleaf forests dominated by different species of oak, viz., Banj oak (Quercus leucotrichophora), Rianj oak (Quercus lanuginosa), Moru oak (Quercus floribunda) and Kharsu oak (Quercus semecarpifolia) along an elevation gradient from 1700–3000 m asl in Gori valley, western Himalaya. Biomass data were collected from 120 quadrats of 10 × 10 m size at three distinct altitudes (4 forest sites × 3 altitudes × 10 quadrats) and analysed for carbon stock, whereas soil samples were randomly collected in triplicate from three depths of each altitude of the forest site and further analysed for their physico-chemical properties. A total of 767 individual trees with a diameter of ≥31 cm were measured at twelve sites and standing biomass was estimated following the growing stock volume equations. Mean carbon stock was highest in Moru oak (396.6 ± 29.5 Mg C ha⁻¹) and lowest in Banj oak forest (189.3 ± 48.6 Mg C ha⁻¹). We also found soil to be the largest pool of forest carbon (43.0–59.7%) followed by aboveground biomass (31.5–45.0%), belowground biomass (8.4–11.7%) and litter (0.4–0.5%). The basal area showed significant effect on altitude and carbon stock, whereas disturbance showed significant (p < 0.05) negative correlation with the total carbon stock. Soil nitrogen exhibited a significant positive correlation (R² = 0.60) with the basal area, indicating that nitrogen enhances tree growth and forest carbon stock. However, anthropogenic disturbance showed a significant negative impact on the basal area, soil nutrients and carbon stock of oak forests. This concludes that forest structure, anthropogenic pressure and soil parameters contribute to the carbon stock of the area. Considering the significance of these overexploited oak forests, it is recommended to conserve the old-growth forest species in the study area, since they have the highest carbon accumulation potential.

Introduction: Riverine forests in the Himalaya represent a biodiverse, dynamic, and complex ecosystem that offers numerous ecosystem services to local and downstream communities and also contributes to the regional carbon cycle. However, these forests have not been assessed for their contribution to dry matter dynamics and carbon flux. We studied these parameters along three classes of riverine forests in eastern Uttarakhand, dominated by Macaranga, Alnus, and Quercus-Machilus forest.Methods: Using volume equations, we assessed tree biomass, carbon storage, and sequestration in the study area.Results: The total standing tree biomass in Macaranga, Alnus, and Quercus-Machilus forest ranged from 256.6 to 558.1 Mg ha⁻¹, 460.7 to 485.8 Mg ha⁻¹, and 508.6 to 692.1 Mg ha⁻¹, respectively. A total of 77.6–79.6% of vegetation biomass was stored in the aboveground biomass and 20.4–22.4% in belowground plant parts across the riverine forests. The carbon stock in Macaranga forest ranged from 115.5 to 251.1 Mg ha⁻¹, in Alnus forest from 207.3 to 218.6 Mg ha⁻¹, and in Quercus-Machilus forest from 228.9 to 311.4 Mg ha⁻¹. The mean annual litterfall was accounted maximum for Quercus-Machilus forest (5.94 ± 0.54 Mg ha⁻¹ yr.⁻¹), followed by Alnus (5.57 ± 0.31 Mg ha⁻¹ yr.⁻¹) and Macaranga forest (4.67 ± 0.39 Mg ha⁻¹ yr.⁻¹). The highest value of litterfall was recorded during summer (3.40 ± 0.01 Mg ha⁻¹ yr.⁻¹) and the lowest in winter (0.74 ± 0.01 Mg ha⁻¹ yr.⁻¹). The mean value of net primary productivity and carbon sequestration was estimated to be highest in Quercus-Machilus forest (15.8 ± 0.9 Mg ha⁻¹ yr.⁻¹ and 7.1 ± 0.9 Mg C ha⁻¹ yr.⁻¹, respectively) and lowest in Alnus forest (13.9 ± 0.3 Mg ha⁻¹ yr.⁻¹ and 6.1 ± 0.3 Mg C ha⁻¹ yr.⁻¹, respectively).Discussion: The results highlight that riverine forests play a critical role in providing a large sink for atmospheric CO₂. To improve sustainable ecosystem services and climate change mitigation, riverine forests must be effectively managed and conserved in the region.

Monitoring resilience in Himalayan forest ecosystem requires an understanding of community structure, regeneration, and anthropogenic disturbances. Four classes of temperate broadleaf forest dominated by different species of oak viz., Banj oak (Quercus leucotrichophora), Rianj oak (Q. lanuginosa), Moru oak (Q. floribunda), and Kharsu oak (Q. semecarpifolia) were assessed between 1700-3000 m asl in Askot wildlife sanctuary, western Himalaya. A total of 300 quadrats of 10x10 m size were placed randomly in 30 forest sites at different altitudes using standard phytosociological methodologies. The tree density ranged from 503±33.8 to 694±75.9 indi. ha-1 with a basal area of 45.0±6.5 to 60.4±6.8 m2 ha-1. Across the forest communities, the sapling density was 590±54.9 to 755±63.4 indi. ha-1 and seedling density was 175±88.5 to 770±208.8 indi. ha-1. Principal component analysis was used to examine the impact of anthropogenic pressures on regeneration of different oak communities. The study reveals that despite the extractive pressures on oak forests in the study area, the regeneration of Q. leucotrichophora and Q. lanuginosa was fair. However, the regeneration of Q. semecarpifolia and Q. floribunda was poor which needs to be protected from livestock grazing. In addition to appropriate management inputs, sustainable forest harvesting practices must be implemented in the region.