Mountain ranges comprise heterogeneous environments and high plant diversity, but little is known about the architecture and structural complexity of trees in mountain forests. Led by researchers from the University of Göttingen, a collaborative international team assessed the relationship between tree architecture, environmental conditions, and tree structural complexity in forests of the Annapurna region in the Himalaya. The study covered 546 trees on 14 undisturbed forest plots across wide ranges of elevation and annual precipitation, which were assessed by ground-based mobile laser scanning. We found that tree structural complexity, expressed as box-dimension, was largely explained by tree architecture, i.e. tree height, crown radius, and crown length explained more than 60% of the observed variation in Db. As expected, tree height decreased with increasing elevation, but small trees often had relatively high Db values. The standard deviation of tree-level Db within a plot explained 47% of the variation in stand-level structural complexity among plots, surpassing the maximum tree-level Db. We conclude that in the Himalayan forests, species identity and tree architecture play a significant role in determining tree structural complexity, while environmental factors have a smaller role. Structural variation among the trees within a plot plays a crucial role for the structural complexity at the stand level.
Reference: Das, S., Basnet, P., Seidel, D., Röll, A., Ehbrecht, M., Hölscher, D. (2025). Tree architecture and structural complexity in mountain forests of the Annapurna region, Himalaya. Ecology and Evolution, 15(4), e71341. https://doi.org/10.1002/ece3.71341
