Tropical Trees May Be More Heat-Resilient Than Expected, New Study Finds

In the Western Ghats of India, researchers are scaling towering trees and installing sensors on their leaves to investigate how tropical forests are responding to global warming. This pioneering study provides the first detailed analysis of cumulative heat exposure in tropical trees—and the findings suggest that these trees may be more resilient than previously believed.

Summer temperatures in the region often exceed 37°C and are projected to rise by another 4°C over the next 60 years. Leaf temperatures typically surpass ambient air temperatures, and when they exceed 46.7°C, photosynthesis shuts down, depriving trees of essential energy. Many tropical tree species have already experienced such extreme temperatures.

However, the study revealed that the duration of high-temperature exposure plays a more critical role than the peak temperature itself. Researchers monitored the leaves of 12 different tree species over four months in a six-hectare plantation. Despite frequent sensor losses due to strong winds and wildlife interference, the data showed that daily leaf temperatures exceeded the critical threshold for less than 10 minutes on average.

Laboratory analyses indicated that the critical temperature threshold for local trees ranges from 43.4°C to 45.5°C—slightly below the global average. Although exposure beyond this range for 30 minutes can cause irreversible damage to leaves, the actual exposure time was relatively brief, suggesting that photosynthetic efficiency remains largely unaffected.

This study offers valuable insights into how tropical forests may adapt to climate change. Despite the logistical challenges of fieldwork, scientists hope to expand the use of temperature sensors in ecosystems around the world to better understand the impact of heat stress on trees. The research not only contributes to forest conservation efforts but also offers a fresh perspective on global warming resilience.