Certain vegetation attributes of three sub-alpine forests, viz., Betula utilis (Birch), Abies pindrow (Fir) and Acer (Maple) mixed forest were studied along a disturbance gradient in and around the Valley of Flowers National Park in Garhwal, western Himalaya, India. The study sites in each forest were classified into non-degraded, semi-degraded and degraded plots based on the intensity of current and past anthropogenic disturbance impacts. In B. utilis forest, density and basal area of trees, and density of herbs and shrubs decreased with increasing disturbance. In Acer mixed forest, the decrease was for density and basal area of trees, and density of herbs. However, in A. pindrow forest, density of trees was highest in the degraded plots and total basal area peaked in the semi-degraded plots. Natural regeneration, expressed in terms of seedling and sapling density in different forest types, revealed the following pattern: (i) in B. utilis forest, the highest density of seedlings and saplings was in semi-degraded plots; (ii) in A. pindrow and Acer mixed forests, the density of seedlings and saplings was highest in the degraded plots. The present study indicates that the compositional attributes of sub-alpine forest communities in western Himalaya are sensitive to anthropogenic disturbances, and the effects varied amongst the forest types and life forms. While compositional attributes of the broadleaved B. utilis forest exhibited a greater sensitivity to disturbance than the other two forests, the coniferous A. pindrow forest was the most resilient.
