What are the characteristics of itchy trees?

Lagerstroemia indica is a precious environmental protection plant in China. People call it "Hundred Days Red" and "Itchy Tree". Just move the bark gently and the branches of Lagerstroemia indica will tremble.

In the dense forest of Xishuangbanna, China, there is a tree whose trunk is very straight, about 3m to 6m high. The largest diameter is only the mouth of the bowl, the bark is brown and smooth, the flowers are reddish purple or white, the petals shrink and the fruit is hidden. This kind of tree has a strange feature. When people gently touch its "skin" with their hands, the branches at the top of the tree will immediately swing from side to side or even shake, as if itching is unbearable, so people call it "itchy tree"