LAUSR

Abstract A study on community structure was carried out along three altitudinal gradients viz., Lower (3000–3200m), Middle (3200–3400m) and upper (3400–3600m) asl in Sindh Forest Division (Sonamarg) and Tangmarg Forest Divisions (Gulmarg) in sub alpine zone of North Western Kashmir Himalayas, India. The floristic structure revealed that Betula stands at Sonamarg forests supported 48 species belonging to 26 families on South Eastern aspect and 53 species belonging to 28 families on South Western aspect, whereas Gulmarg forest was represented by 54 species of 28 families. The overall community structure of Betula stands depicted that Asteraceae, Poaceae, Rosaceae and Lamiaceae were the dominant families in these timberline forests. The dispersion showed that 65.48% species were contagiously distributed, 25.67 and 8.85% species showed random and regular distribution. Betula utilis shared the top niche with the dominance of 61.56 and 76.27% on SE and SW aspect at Sonamarg, and 71.81% at Gulmarg. Species richness decreased with elevation and species diversity of the forest was relatively low, the decrease in these parameter with increasing altitude can be directly related to high grazing pressure, harsh climatic conditions, topography and snow, which covers these areas for longer times especially during the growing season.