Jeet Ram

Anthropogenic disturbances and plant biodiversity in forests of Uttaranchal, central Himalaya

Eight forest types varying in disturbance frequencies were identified along an elevational gradient in Uttaranchal, central Himalaya. Low elevation forests were close to human habitation and had high disturbance frequency, while high elevation forests were situated far from the human habitation and had low disturbance. The dominant tree species at low elevation were Pinus roxburghii and Quercus leucotrichophora, while Q. floribunda and Q. semecarpifolia dominated the high elevation forests. Pyracantha crenulata was the shrub present in all the forests except in Q. semecarpifolia forest and Anaphalis contorta, a herb species, was present in all the forests. Disturbance decreased the dominance of single species and increased the plant biodiversity by mixing species of different successional status. Species richness and diversity for all the vegetation layers were higher in low elevation–high disturbance forests. Mean tree density decreased from high to moderate and increased in low disturbance. The shrub density decreased from high to low disturbance while the reverse occured for herbs. High proportion of early successional species in disturbed forests indicated that disturbance induces succession. The mean number of young individuals increasing from high to low disturbance indicates that disturbance adversely affects regeneration. But, however, the high number of young individuals of Coriaria nepalensis, a small non-leguminous nitrogen fixing tree, in disturbed forests shows that the forest is regenerating. This species could be helpful in the re-establishment of original vegetation through triggering the regeneration of these forests. High elevation–low disturbed forests separated from low elevation–high disturbed forests. Forest type and elevation may have more influence on tree richness while shrub and herb richness may be more sensitive to disturbance and forest types.

Human Influence on Banj Oak (Quercus leucotrichophora, A. Camus) Forests of Central Himalaya

The present study suggests that the impact of human-induced small-scale disturbances (lopping of branches and leaf litter removal) adversely impacts the functioning of banj oak (Quercus leucotrichophora, A. Camus) forests of Central Himalaya. Significantly higher (p < .001) biomass stocks, carbon sequestration rates, soil carbon, leaf area index (LAI), litter fall, and faster litter decomposition rates were observed in least human influenced (LHI) forests as compared to moderately human influenced (MHI) forests and highly human influenced (HHI) forests. Three replicate forest stands of each category were selected for the observation. The study is used as a background to suggest alternative strategies to conserve the forests, taking into account the social and economic concerns of the village community.

Effect of collection date on capsule moisture content and germination of Populus ciliata Wall. ex Royle from central Himalaya

Seed maturity indices of Populus ciliata were investigated in collections from Sukhatal and Bhowali. Across both seed sources, mean capsule size varied from 68.0±1.5 mm2 to 72.0±0.9 mm2, while mean number of capsules/100 grams varied from 268±8 to 295±12. Mean weight of 100 capsules varied from 25.0±1.4 g to 27.0±1.4 g. Weight of 100 capsules among sources and individual trees differed significantly (P < 0.05), while number of capsules/100 grams and weight of 100 capsules was negatively correlated (r2 = 0.69). As capsules matured moisture content decreased from 83.2±1.1% to 54.3±0.3% at Sukhatal and from 77.7±0.4% to 46.4±0.3% at Bhowali. The optimum germination was at 58–60% moisture content. Maturation was related to capsule colour changes as well as moisture content. These parameters were judged to be good indicators of when to collect P. ciliata seeds.

The effect of natural and anthropogenic disturbance in forest canopy and its effect on species richness in forests of Uttarakhand Himalaya, India

Pinus roxburghii (chir-pine) and Quercus leucothchophora (banj-oak) are dominant forests of mountainous part of the Uttarakhand Himalaya. The continued anthropogenic disturbance is opening the canopy, forming canopy gaps and as a result forest fragments are developing. Thus, the present study aims to analyze variations in species richness and vegetational parameters in relation to canopy gaps in forests. Total species richness was greater in open canopied forest compared to moderate and close canopied forests. In comparison between oak and pine forest, it was greater in oak forest while the proportion of common species was low between oak—pine forests. Mean species richness did not significantly vary from one canopy gap to another as well as in oak and pine dominated forest. This indicated that dominant forest types played an important role to form the community structure. The shrubs richness were greater in closed canopy and between the forests it was greater in pine forest. Tree and shrub density was low in open canopy while herb density was high in moderate canopy. Thus, this study indicated that the dominant canopy species play an important role in deciding the community structures especially the distribution of under canopy species. These parameters should be considered for conservation and maintenance of plant biodiversity of a region.

Seed and seedling characteristics of the Himalayan hornbeam ( Carpinus viminea Wall.), India

To study of seed and seedling characteristics, seeds of the Himalayan Hornbeam (Carpinus viminea Wall.) were collected from low and high-elevation sites during the peak maturation period. Paired t-tests indicated that seed weight, percentage of sound seeds, and germination were significantly greater for high-elevation seeds whereas seed moisture (%) was low. Seedling growth performance was better for high-elevation seeds than for those from low elevation. This indicates that environmental conditions at high elevation may favour germination and seedling growth of the species.