Research Shows Some Tropical Trees Can Cool Their Leaves To Survive Heat, But Many Are At Risk

Discover how some tropical trees regulate leaf temperature to survive scorching heat. A new study reveals the fascinating adaptations of certain species and the implications for conservation in a changing climate.

Some tropical trees can cool their leaves to survive in hot weather. However, not every tree has this ability. On a hot day, you might seek shade, use a fan, or go somewhere with air conditioning. But trees can't move or turn on a fan. As the climate gets warmer, these trees must find a way to cope with the heat, adapt over time, or risk dying slowly.

Tropical trees face a big challenge: when their leaves are in direct sunlight, they can get much hotter than the air around them. If the leaves get too hot, photosynthesis can slow down or even entirely stop. Photosynthesis is how plants make food and survive, so it's very important to keep the leaves cool.

In hot climates, some plants cool their leaves by evaporating water through tiny holes called“stomata” on the leaf surfaces. This is similar to how sweating helps cool your skin. Other plants have smaller and narrower leaves. These types of leaves lose heat more easily because the wind can blow closer to the leaf surface. Some trees also change how their leaves are positioned to catch less sunlight.

Scientists call this process“thermoregulation,” the ability to control leaf temperature.

This new research was published in Wiley Online Library. Scientists looked at trees in the Wet Tropics of Queensland, Australia, from warm lowlands up to cooler mountaintops. They studied three species: silky oak, blue quandong, and bull oak. They measured different features of the leaves, like size, thickness, colour, and how much water they released through stomata to cool down.

The results showed that silky oak and blue quandong tree can cool their leaves better in hotter environments by opening their stomata more and having narrower, smaller leaves.

To understand if some tree populations evolve over generations to handle heat better, the researchers checked the DNA of tree populations growing in different climates. They found that climate has shaped their genes over time. However, not all these changed were related to cooling leaves. For example, bull oak's generic changes might help with other functions, not temperature regulation.

This suggests that some tree populations have evolved genes that help them control leaf temperature. This information is useful for conservation: it can help decide where to collect seeds for planting trees that can survive better as the climate warms.

The study shows that some tree species have natural ways to handle higher temperatures, but others do not. Trees that can't keep their leaves cool may suffer damage, grow less, or even disappear from some areas as the planet warms. It helps scientists and conservationists protect tropical forests and the life they support in a changing world.

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