How does Cyclobalanopsis forecast the weather?

In China Guangxi New Town, a Qinggang Tree grows. 20 meters high and 70 centimeters in diameter, 150 years old.

This is an evergreen tree, which grows anywhere south of the Yangtze River in China. But this kind of new town is different. Its leaf color will change regularly according to the climate change.

In sunny weather, the leaves are dark green; When it rains, the leaves will turn red; After the rain clears, the leaves will return to their original colors.

Because people can watch trees and measure the weather, this ancient tree naturally becomes a natural meteorological station deeply loved by local people. Why is it that under the same temperature, humidity and air pressure, among many Qinggang Tree trees, only this one has "special functions"? Worth studying.