Why does a rainforest tree have no lower branches?

Rainforest trees typically lack lower branches due to a phenomenon called "self-pruning," where trees shed lower limbs to allocate resources more efficiently to higher branches that receive better sunlight. Additionally, as trees grow taller to compete for light in the dense canopy, their lower trunks become shaded, making it less viable for lower branches to thrive. This adaptation allows the tree to maximize photosynthesis and survival in the competitive environment of the rainforest.