Carbon stock assessment across temperate forest types along an altitudinal gradient in Tehri, Garhwal Himalaya

Forests serve as crucial reservoirs of carbon, playing a vital role in mitigating global climate change by storing atmospheric carbon in biomass and soil. The Himalayan forests, characterized by their ecological diversity and altitudinal gradients, are especially significant in this regard but remain underrepresented in localized carbon stock assessments in the study area. The present study evaluates the carbon stock potential of ten major forest types (FT) along the altitudinal gradient in Tehri Garhwal, Uttarakhand, using non-destructive, field-based approaches. A total of ten quadrats (31.62 m × 31.62 m) were established in each forest type, and data on tree diameter at breast height (DBH ≥ 10 cm), height, and species-specific growing stock volume were collected. Carbon stock estimates were derived through biomass expansion factors and carbon fractions specific to hardwoods and conifers. Results revealed substantial variation in biomass and carbon density across forest types and altitudes. Total carbon density (TCD) ranged from 143.0 ± 14.14 tC ha−1 in mid-altitude Quercus leucotrichophora stands (FT2) to 308.53 ± 31.61 tC ha−1 in Cedrus deodara-dominated forests (FT5). Among individual species, Cedrus deodara and Abies pindrow exhibited the highest carbon storage capacities, while lower contributions were observed in species such as Symplocos paniculata and Acer cappadocicum. Variation in carbon stock was strongly influenced by factors species composition, altitude, and forest type. These findings highlight the significant carbon sequestration potential of conifer- and broadleaf-dominated forests in the Garhwal Himalaya, offering critical baseline data for climate change mitigation, forest management, and regional carbon budgeting.