<p>Fine root production plays a critical role in nutrient cycling, soil carbon dynamics, and ecosystem biodiversity. This study assessed the seasonal and forest-type variations in fine root production, herbaceous diversity, and soil nutrient concentrations across pure oak, pure pine, and mixed oak-pine forests in the Central Himalaya. Fine root production peaked during the rainy season, with pure oak forests exhibiting the highest live and total root production, while dead root production was greatest in winter. Mixed forests showed intermediate production values, suggesting facilitative interactions between species. Herbaceous diversity closely mirrored root production trends, with higher herb density and species richness associated with greater fine root biomass, particularly in oak-dominated forests. Seasonal peaks in herb diversity were observed during the monsoon, highlighting the importance of climatic conditions in regulating plant community dynamics. The production of fine roots was correlated with herb diversity in both oak and pine mixed forests; this correlation was more significant in mixed (<i>r</i>^<i>2</i> <i>=</i> 0.813 in oak and <i>r</i>^<i>2</i> <i>=</i> 0.495 in pine) compared with pure (<i>r</i>^<i>2</i> <i>=</i> 0.656 in oak and <i>r</i>^<i>2</i> <i>=</i> 0.338 in pine) forests. Monthly variations in the production of fine roots and herb diversity were examined in mixed and pure banj oak and chir-pine forests. Soil nitrogen and organic carbon concentrations were significantly higher in pure oak forests and positively correlated with herb richness across all sites. These findings emphasize the pivotal role of fine roots in shaping aboveground diversity and soil fertility. Mixed-species forests demonstrated resilience and enhanced ecosystem functioning, underlining their conservation value in Himalayan landscapes under changing environmental conditions.</p>