Floristic Dynamics of Woody Species in Chir Pine ( Pinus roxburghii ) Forests along an Altitudinal Gradient in Himachal Pradesh

Floristic dynamics of a community is the indicator of variation in climate, soils, habitat, and physiography of the area. Study was conducted in the zone of occurrence (800 - 2,200m amsl) of Chir pine forests in Himachal Pradesh. Entire study area was grouped in the three altitudinal zones i.e., 900 - 1,200m, 1,201 - 1,500m (Shiwalik Chir pine forests) and 1,501 - 2,000m lower Himalayan Chir pine forests. It is observed that majority of the tree species showed contiguous distribution pattern, whereas, shrubs showed contiguous and random distribution. Study on density- dominance interaction showed that trees mainly showed log-normal and geometric series of distribution while in case of shrubs log series were of common. Results revealed the lower Himalayan Chir pine forests are less diverse in respect of tree species, having Quercus leucotrichophora dominant associate followed by Pyrus pashia and more diverse in case of shrubs as compared to that of shiwalik Chir pine forest where associated tree species are Syzygium cuminii, Lannea grandis and Myrica esculenta followed by Pyrus pashia, Mallotus philippinensis and Cassia fistula . Studies revealed that floristic dynamics, dominance, distribution of woody species change with change of aspects and altitudes.