- 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.
- Timberlines, the uppermost limit of canopy forests that gradually gives way to the treeline (beyond which trees do not grow) are limited by climate: factors including low temperatures and high winds on mountain tops prevent woody tree growth higher up.
- Timberlines, therefore, serve as indicators of climate change.
- 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.
- Bhutan fir seedlings regenerated well here and elevation (along with humus and slope) played a role in this regeneration too.
- The zone contained high numbers of seedlings and saplings.
- The ecotone could become denser in the near future.
- However, there were no tree seedlings or saplings beyond the treeline.
