Why do poplars lose their white hair in spring?

It's poplar catkins, the seeds of poplar, and the flocculent fluff wrapped outside. They floated down from the poplar and were produced after the female flowers of poplar were fertilized and the seeds matured. The principle is similar to dandelion, the purpose is to spread seeds with the help of wind.

Spring is the mature period of Chinese white poplar capsule (fruit). After the fruit is cracked, the seeds float in the air with the help of white catkins, which is an important way of poplar propagation. Populus tomentosa is suitable for planting in northern China (such as Beijing) and was once the main tree species for urban road greening in Beijing. With the growth of tree age, the fruit yield of Populus tomentosa increased, and the white catkins easily fluttered with the wind.