Vegetation Dynamics in Treeline Ecotone of Langtang National Park, Central Nepal

A study was carried out at the treeline ecotone (3,730m-3,950m asl) of Langtang National Park in central Nepal with an aim to document the impact of climatic warming on ecological chracteristics. Three sampling sites were selected at Chaurikharka and Lauribina, where no serious anthropogenic pressure was noticed. The nearest meteorological station has records of climatic warming in recent years. Six tree species and three shrub species belonging to seven families were enumerated from the study plots. The average basal area for tree species was found to be 20.56 m2 per ha while average tree density was found to be 734 trees per ha with Abies spectabilis as dominant species. The mean DBH (diameter at breast height) of tree species was found to be 15.8 cm (max. 115.5cm). Density of dead trees accounted 2 no. per ha with basal area 0.195m2 per ha. Average sapling and seedling density of tree species per ha was observed to be 1,590 and 831 respectively. The average sapling and seedling density of A. spectabilis was 255 and 350 per ha respectively. Similarly, average shrub density (per ha) for the area was found to be 9,609 no/ha. The stand character showed that there was high level of recruitment of A. spectabilis in the recent years. The presence of sapling and seedling of A. spectabilis at higher altitude showing linear relationship with canopy coverage indicated prospects for a gradual and upward shift of A. spectabilis with increased temperature.