2.1. Study area
The study was carried out at the Kedarnath valley of Rudraprayag district (30° 31. 44.7” N, 79° 6’ 21.1” E and altitude 1604 masl) of Central Himalaya (Figure 1). The study area has a generally cold temperate type and a strongly seasonal climate.  The mean annual precipitation ranged from 1971 mm, and most of this fall between June through September with moderate to heavy snowfall during December-February. The study area falls in the external zone of the Kedarnath wildlife sanctuary. The study area has steep hills along with undulating topography and influenced by landslide/slips during the rainy season. The soil is brown-black in color and podzolic, which is generally gravelly and large boulders are present in the area (Table.1). The study sites lie within the central axis of central Himalaya, which consists of belts of metamorphic rocks along with granites, gneiss, and schist referred to as the critical crystalline (Raina and Gupta 2009). The primary tree species in the study area are Alnus nepalensisD. Don, Quercus leucotrichophora A. Camus, Rhododendron arboreum Smith, Myrica esculenta Buch.-Ham, Litsea umbrosa Nees, Lyonia ovalifolia (Wall.) Drude, Symplocos paniculata Miq, Pyrus pashiaL (Table.1).