Ring-cupped oak, also known as Quercus glauca,is a subtropical tree species. It is commonly found in the south of China.

There is also a famous nickname for the tree - "weather tree". How can the tree be related to the weather? This is due to its unique "temperament" and "ability".

It turns out that the tree is very sensitive to changes in the surrounding climate conditions. It can change the leaf color through changing the chlorophyll and anthocyanin ratio contained in the leaves, so as to "forecast" the recent weather changes.

According to observations, after a long-term drought, just before the rain, in the case of strong light and sultry days, the chlorophyll synthesis of the ring-cupped oak is blocked, so that anthocyanin in the leaves is dominant, and the leaves gradually turn red. However, after the rain, the leaves are dark green again.

Therefore, farmers in some places, based on their usual observation of ring-cupped oaks, have drawn out lessons: when the leaves turn red, it will rain heavily in this area within a day or two. Farmers use this information to speculate on weather changes and arrange farming activities.

In addition, the vitality of the ring-cupped oak is strong. It can withstand cold and drought. Its outer bark is extremely rough, and it is a kind of skin that is close to dry, like people's chapped lips. However, its inner material is extremely moist and tough. The wood is generally used for railway sleepers, as well as for furniture and utensils.