Naba Raj Gurung , Prem Lall Sankhayan , Ole Hofstad , Bishal K. Sitaula

Abstract

A study was carried out in Mardi watershed in Nepal to estimate the stem volume and biomass and analyze the factors responsible for their variations in different forest types.Tree height and diameter at breast height were measured in nine sample quadrants each in Mixed Hardwood Forest (MHF) and Oak Forest (OF) and 13 sample quadrants in High Mountain Mixed Forest (HMMF) for 56 tree species.The per hectare stem volume and biomass of trees in HMMF and OF was 2 to 3.5 times higher than that in MHF.The mean volume per hectare was 2.3 and 2.7 times higher and the stem density 2.5 and 2.7 times higher in the conservation area as compared to regional and national averages. Mean volume and biomass in the forests with high accessibility and low altitude differed significantly from those with medium and low accessibility and medium and high altitude.Mean volume and biomass did not vary significantly by s]ope classes and aspects.Distance, altitud.e and slope explained up to 93 percent of the total variation in OF biomass. The usefulness of the study lies in providing baseline data for analyzing the changes in forest health, measured in terms of biomass and volume.

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Sanjeev , Mohit Gera , Prem Lall Sankhayan

Abstract

The present study was carried out in Arnigad micro-watershed covering an area of 13.43 km² in Mussoorie hills of Garhwal Himalayan region. For the purpose of characterizing the species composition, vegetation structure and floristic diversity by land use categories, the entire watershed was delineated into four land uses, viz., forest, scrub forest, degraded and agricultural lands. In all, 64 species belonging to 63 genera and 56 families were found to be growing in the micro-watershed. The vegetation analysis showed that Quercus leucotrichophora, Acacia catechu, Eucalyptus spp. and Juglans regia were found to be dominant in forest, scrub forest, degraded and agriculture lands respectively for the tree stratum. Similarly Berberis aristata and Lantana camara were observed to be dominant in the shrub communities of forest and scrub forests respectively. Lantana camara was also found to be dominant in the shrub communities of degraded land. Results of the diversity index, concentration of dominance and equability on the three land uses, viz., forest, scrub forest and degraded land indicated that maximum diversity was observed in forest with respect to tree stratum followed by scrub forest and degraded lands, whereas in case of shrub and herb strata, scrub forest showed the maximum diversity. The maximum values on dominance were recorded for all the three strata of vegetation on degraded land indicating the presence of single or few species. The vegetation recorded on scrub forest was found to be more equitable compared to vegetation on forest and degraded land.

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