Structure, Composition and Diversity of Forest Along the Altitudinal Gradient in the Himalayas, Nepal

Abstract

Abstract. The aim of this study was to assess the structure (stem density, height, and basal area), composition and diversity in relatively undisturbed forests along an altitudinal gradient from 2000 m asl to 3900 m asl of Langtang National Park in Central Himalaya. The forest stands along the altitudinal gradient were studied on 20 sampling plots of two sub zones of the Temperate and Subalpine zone. Tsuga dumosa was the ecologically most important species in the Upper and the Lower Subalpine zone with high important value index (IVI = 124.31). Quercus semecarpifolia and Lithocarpus elegans were the ecologically most important species in the Upper and the Lower Temperate zone with IVI of 66.64 and 46.39 respectively. Similarly, indicator species' analysis was performed to know the preferences of tree species within the vegetation zones. Rhododendron campanulatum is highly significant (p < 0.001) and Tsuga dumosa significant (0.05 < p < 0.01) in the Upper Subalpine zone, whereas Rhododendron anthopogon prefers the Lower Subalpine zone with significant value (0.01 < p < 0.001). Only the Quercus semecarpifolia prefers the Upper Temperate zone. There was no specific trend in the structure along the altitudinal gradient. The Shannon diversity index ranged from 1.10 to 2.34 with the highest value in the Lower Temperate zone. Both Simpson index (0.89) and Evenness (0.86) were high in the Lower Temperate zone. From this study it is concluded that the contribution of forest composition in terms of species richness and Shannon diversity is significant in Lower Temperate zone. The Upper Subalpine zone has less diversity and may also be less endangered by human impact but may profit from climate change in the future.

Forest Structure and Composition under Contrasting Precipitation Regimes in the High Mountains, Western Nepal

“…Furthermore, the inverse J-shaped pattern documented for overall size class distribution in this study is similar to the findings of Bhutia et al [32] who found the highest number of individuals in the smallest DBH class of 3 to 13 cm and least in the highest class in Eastern Himalayan, India. This pattern is further supported by the findings of Shrestha et al [139], Dar et al [140], Pandey et al [127], and Schwab [141]. More than 90% of trees were found in lower diameter classes in the Himalayan forest of India [140].…”

“…More than 90% of trees were found in lower diameter classes in the Himalayan forest of India [140]. Pandey et al [127] recorded maximum percentages of trees in the DBH range of 10 to 29.9 cm in the trans-Himalayan region of Nepal. Most tree species in the Krummholz tree line of Rolwaling Himal, Nepal in the lower DBH range i.e., 0-14 cm were Abies spectabilis, Betula utilis, Sorbus microphylla and Rhododendron campanulatum [141].…”

“…In lower-elevation tropical forests, higher species diversity and richness were recorded in high precipitation regions than dry regions in Myanmar by Khaine et al [123], and in mangrove forest [124] and sub-Saharan Africa [125] as well. Regarding forest structure, most studies [1,32,[126][127][128] have focused on Himalayan vegetation patterns along altitudinal gradients, though few have mentioned the importance of climate variables in predicting forest stand structure [21,129,130]. Considering forest structure varies with water availability [131], and environmental and biological factors control forest structure at higher elevations [132,133], this study tried to assess differences in forest structure along a precipitation gradient in the Annapurna range.…”

Assessing Forest Structure and Composition along the Altitudinal Gradient in the State of Sikkim, Eastern Himalayas, India

“…Studies in the Eastern Himalayan forests outside of India were mainly carried out in Nepal [25,26], Bhutan [27][28][29], and China [30,31] to assess forest structure and composition. Within the Indian part of the Eastern Himalayas, studies were carried out in Arunachal Pradesh [32][33][34], Meghalaya [8,35,36], Darjeeling, West Bengal [37], and Assam [38,39].…”

Variation of Floristic Diversity along Altitudinal Gradient in Pir Panjal Forests of North Western Himalaya, India

“…The floristic diversity has been documented throughout the globe including India and in India all the Himalayan states like Uttarakhand, Himachal Pradesh, J&K have been covered [23][24][25][26][27]. In J&K number of studies on floristic diversity has been conducted by different workers [28][29][30][31] but the site Raithan range of Pir Panjal Forest Division, J &K, India was yet to be explored for floristic diversity and ecological study, therefore keeping in mind the importance of this study for conservation of plant ecology and sustainable utilization, this study has been conducted to assess the floristic diversity and community characteristics at different altitudes of Raithan range of Pir Panjal Forest Division, J &K, India .…”