Studies on Subalpine Forests of Hamta Pass Area in Himachal Pradesh, India with A Focus on Betula utilis Populations

The present study was conducted in Hamta Pass area of Kullu district, Himachal Pradesh, India with a focus on Betula utilis populations. Totally 16 populations of B. utilis representing four habitats and three aspects were studied. The maximum sites were represented by moist and moist, shaded habitats with northwestern aspect. Totally 188 plant species representing trees, shrubs and herbs were recorded. Acer acuminatum, Abies pindrow, Prunus cornuta and Quercus semecarpifolia were the major associated species of B. utilis in the subalpine zone of Hamta Pass. Based on importance value index five tree communities, namely A. acuminatum, A. pindrow, B. utilis, Q. semecarpifolia and B. utilis–P. cornuta mixed were identified. Among the communities, total density of trees, shrubs and herbs was recorded from 160 to 270, 300 to 515 and 21 to 33 individuals m^–2 respectively. The total basal area recorded was 6.94–42.10 m2 ha^–1, species richness 15–127, and species diversity for trees 0.4–0.9, shrubs 0.0–2.1 and herbs 1.7–4.2. The density and regeneration (i.e. seedlings and saplings) of B. utilis in most of the populations revealed that this species will continue to grow in the area. However, continued anthropogenic activities, climate change and other factors may cause population depletion in the study area.