Plant Species Diversity, Composition, Gradient Analysis and Regeneration Behaviour of some Tree Species in a Moist Temperate Western Himalayan forest Ecosystem

Vegetation composition, species diversity, distribution pattern and other parameter of vegetation analysis along with the population structure and regeneration behaviour of some tree species in a Western Himalayan forest of Chakrata Forest Division (Uttaranchal) were studied. The possibility of future composition changes was also explored. The whole area is divided into three sites as per their aspect and altitudes (site-I - alt. 1,700 masl, aspect N-Ej site-II - alt. 2,050 masl, aspect, N, and site-III, alt., 2,100 masl, aspect, N-W). The communities for these sites were identified as Cedrus deodara forest (site-I),
Cedrus deodara-Quercus leucotrichophora-Pinus wallichiana (site-II) and
Q. leucotrichophora-C. deodara-P. wallichiana (site-III). Total density range for the tree species (plant 100 m-¹) was 4.51-6.64; 23.56-41.62 for shrubs and 7,280-11,920 for herbaceous species; while the range for total basal cover (cm² 100m-² ) was in between 0.332-0.938 for trees; 9.50-18.81 cm²100m-² for shrubs and 235-323 cm²100 m-² for herbaceous species. Most of the species in all the sites showed contiguous pattern of distribution, however some species were also randomly distributed. Maximum diversity of trees was observed for site-III and for herb and shrubs species diversity values were highest for sites II and III respectively. However, lowest diversity was recorded for the herbaceous layer in site-III. Further, increasing altitude showed increase in tree diversity. Concentration of dominance showed reverse trend to diversity. Sites II and III were most similar sites, whereas sites I and III were most dissimilar sites. Highesio turnover of tree species was recorded between sites I and III; for shrub species, these were site-II and III and maximum turnover for herb species was recorded between sites I and II. In all the studied sites, the dominant species has shown good regeneration potential as evidenced by the presence of adequate number of seedling, sapling and distribution of boles among almost all gbh classes.