Tree composition, regeneration potential and anthropogenic disturbances across major forest types of Rajouri in the Pir Panjal region of north-western Himalaya

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The sustainability of forest ecosystems is closely linked to ecological indicators such as tree species composition, diversity, population structure, and regeneration potential. This study assessed these parameters across four major forest types: Pine, oak, fir, and mixed along an elevational gradient in Rajouri district, Jammu and Kashmir, India. A total of 640 nested quadrats of various sizes were established across 16 systematically selected sites and key phytosociological parameters were computed. In total, 35 tree species belonging to 30 genera and 19 families were recorded, with Fabaceae being the most species-rich family. Tree density ranged from 345 ± 136.99 individuals (Ind) ha −1 in fir forest to 845 ± 336.70 Ind ha −1 in mixed forest, while basal area was highest in fir forest (87.47 ± 33.64 m 2 ha −1 ), indicating the prevalence of mature, large-diameter conifers. Mixed forest exhibited the highest seedling (1362.5 ± 714.58 Ind ha −1 ) and sapling (1090 ± 396.32 Ind ha −1 ) densities, followed by oak forest, which also showed robust regeneration and a reverse J-shaped population structure. In contrast, pine and fir forests showed limited recruitment, with skewed DBH distributions dominated by mature individuals, reflecting regeneration bottlenecks. Diversity indices including Shannon-Wiener, Simpson’s, Margalef, and Fisher’s alpha were significantly higher in mixed forest, followed by oak, and lowest in fir forest, highlighting the structural complexity of mid-elevation sites. Canonical Correspondence Analysis (CCA) revealed strong associations between species distribution and anthropogenic disturbances such as forest fire, resin tapping, grazing, lopping and logging, particularly affecting conifer-dominated forests. These findings highlight the need for targeted conservation measures, including regeneration support and disturbance mitigation, to enhance ecological resilience and sustain forest biodiversity in the northwestern Himalaya.