The giant trees of tropical forests are important allies in the fight against climate change because of their ability to store carbon, yet they are still poorly understood by science. However, a study published in the journal Science reveals a crucial survival mechanism: These trees, which exceed 70 meters (230 feet) in height, have no difficulty transporting water to their tops and are no more vulnerable than smaller trees.

They have developed internal adaptations that compensate for the challenges of transporting water to the highest branches. Furthermore, tests conducted during severe droughts showed that they did not experience a more pronounced decline in growth than smaller trees. This contradicts the hypothesis that very tall trees would be more susceptible to water stress.

How giant trees move water
To date, the scientific literature suggests that as trees grow taller, their ability to move water upward is impaired by the greater distance between roots and leaves, as well as by the effects of gravity. This would reduce photosynthesis, limit growth and increase vulnerability to drought.

The research found that adjustments to the xylem conduits (microscopic "tubes" that the plant uses to transport water and nutrients to the leaves)—which increase in diameter as the tree grows taller—compensate for the increased resistance to water flow along the way. In practice, it's as if a larger hose were needed to carry water further. These complex adaptations reduce the likelihood of water transport failure when the plant is in drought conditions.