Lianas explore the forest canopy more effectively than trees under drier conditions

Lianas rely on trees for support and access to high light positions in the forest canopy, but the implications for how lianas explore the canopy compared to trees remain understudied. We present an in situ forest canopy study to test the hypotheses that: (1) lianas favour leaf display over stem investment compared to trees and (2) lianas have greater potential to colonize non-shaded, high-light areas effectively than trees. We compared branches of 16 liana species with those of 16 sympatric tree species in two lowland tropical forest canopies in Panama using 40-50 m tall canopy cranes. One forest was relatively dry and seasonal in rainfall and in associated light availability. The other forest was relatively wet and evergreen. We observed that lianas were more efficient in leaf display over stem investment than trees, particularly in the forest with lower precipitation and stronger seasonality. Specifically, lianas had a lower LMA (leaf mass per unit leaf area), stronger apical dominanc...