<p><i>Quercus semecarpifolia</i> Smith. (Kharsu/Brown oak) is an evergreen, high altitudinal and late successional gregarious oak specie which serves as a significant reservoir of carbon in its biomass and provides an essential source of green fodder during winter. The study involved the estimation of the biomass and carbon stock of <i>Q. semecarpifolia</i> forests, along with soil physicochemical properties and leaf nutritional value along an altitudinal gradient of the northwestern Himalayas in India. The study area was divided into three altitudinal ranges i.e. A1 (2500–2800 m), A2 (2800–3100 m) and A3 (3100–3400 m). Each altitude range had four sites (i.e. S1, S2, S3 and S4) located at different elevations. The tree biomass was estimated using a non-destructive method. Soil samples were randomly collected from representative sites for the analysis of physicochemical properties. Leaf samples were collected from three different portions of the trees (viz. top, middle and bottom) to assess nutritional parameters. The results revealed that the maximum carbon stock (109.01 MgC ha^-1) was observed at A3, while the minimum (69.47 MgC ha^-1) at A1. Moreover, soil moisture content, water holding capacity, soil organic carbon, nitrogen, phosphorus and potassium increased with altitude, whereas, bulk density, pH, electrical conductivity and exchangeable calcium decreased with increasing altitude. Similarly, leaf nutritional parameters, such as crude protein, ether extract, organic matter, leaf phosphorus, total digestible nutrients, dry matter digestibility, digestible energy and metabolizable energy also increased with increasing altitude. However, fibre, ash and leaf calcium content showed a declining trend along the altitudinal gradient. This study would help to improve our understanding of the carbon sequestration and storage potential of <i>Q. semecarpifolia</i> forests and enhances the knowledge of their leaf nutritional value for livestock in high-altitude regions.</p>