J.P. Mehta, B. S. Bhandari and Prashant Arya
The study was undertaken to elicit the structural associations and diversity status of some montane forest stands of Garhwal Himalaya with special reference to altitude and aspect. A total of six sites were investigated at differing altitudes in two opposite mountain flanks. Cedrus deodara emerged as the dominant tree species on most of the forest stands. However, lower and middle gradients were found to be more suitable habitat of this species. Competition between Quercus leucotrichophora and Pinus roxburghii on the forest stands is attributed to peculiar bioedaphic factors prevailing in the mid altitudes of this Himalayan region. Further, invasion of Pinus roxburghii and competition with Quercus leucotrichophora (Oak) thereafter, is an indication of Oak replacement in near future. Eastern faces were much richer in shrub diversity due to relatively longer insolation on comparatively open habitats of eastern faces. Low values of beta-diversity were due to dominance of more or less similar species associated with poor species richness. Gradual change in the similarity and dissimilarity from lower to upper gradients through middle reflected the impact of altitude on the structure of forest stands. It was remarkable in this study the dominance of broad-leaved species has been successfully masked by gymnosperms on all the forest stands. This should be viewed with far-sighted and skilled management practices in the ecological defined territory of broad-leaved forests mainly dominated by Oaks and associated species in this altitudinal range of Uttarakhand Himalaya.
Keywords: Altitude, Montane forest, Structure, Diversity, Competition, Dominance, Gymnosperms, Oak, Garhwal Himalaya.