The cold climes on high-altitude mountain tops make it usually difficult for trees to grow above the timberline (the last canopy forests on the mountains). Though global warming is changing this in many of the world’s high mountains and causing timberlines to move upward.
The eastern Himalaya may be an exception, find scientists. The zone of uppermost canopy forests here are unlikely to shift upwards but will get denser, suggests a study in PLOS ONE.
Scientists from institutes including Sikkim’s G. B. Pant National Institute of Himalayan Environment and Sustainable Development studied the composition and regeneration of woody trees in the timberline ecotone (transition zone) between the timberline and treeline, of Khangchendzonga National Park.
Across nine contiguous sites in the Park, the team studied tree composition in this ecotone which lay between 3,787 and 3,989 metres above sea level.
Among the 20 woody tree species they recorded here, the Bhutan fir Abies densa, the woolly rhododendron Rhododendron lanatum and the small-leaf rowan Sorbus microphylla dominated the vegetation.
Environmental factors such as elevation, slope and humus played a role in this species composition. The density of trees in the timberline ecotone was significantly higher than that of its western Himalayan counterparts.
According to the authors, this indicates that the ecotone could become denser in the near future.
Reference- The Hindu