People's Daily Online, Beijing, April 8 (Reporter Yin Xingyun) On April 7, the Beijing Municipal Bureau of Landscaping and the Beijing Meteorological Bureau jointly released the initial forecast of willows and catkins in Beijing in 2024. The joint forecast is convenient for citizens to understand and scientifically respond to the natural phenomenon of willow catkins, and at the same time, it guides the city to carry out accurate and scientific comprehensive prevention and control to minimize the impact of catkins on the production and life of citizens.

Willow is a native tree species in Beijing with a long history of planting. It is also a contributor to Beijing's ecological construction and a pioneer in Beijing's urban greening. As a landmark plant variety in Beijing, poplar is the largest tree species in Beijing and one of the trees that sprouted earliest and fell last in Beijing.

Willow trees are dioecious, and catkins come from the female trees of willow trees. After pollination in spring, the female inflorescences generate small capsules, which are covered with white flocculent villi, and some seeds smaller than sesame seeds are hidden in the villi. The mature small capsules gradually split, and the white flocculent villi carried the seeds flying in the wind, spreading the seeds by the wind, forming "willow flying catkins", which is a normal physiological phenomenon of plants. Generally, in the first ten days of April, Populus tomentosa in Beijing first enters the catkin flying period, and willow catkins start the flying season after about 10 days of catkins flying.

Through monitoring the dynamic development of fruit order and meteorological conditions of willow female plants, the garden greening and meteorological experts jointly discussed and judged the initial forecast of willow catkins. According to the forecast, the central and southern urban areas will enter the batting period from April 7 to 10. Later in the northeast and northwest of the city, the catkins began to fly from April 8 to 11.

Willow catkins have obvious periodicity and seasonality. Influenced by tree species, greenhouse effect, heat island effect and microclimate environment temperature, the catkins flying period generally lasts about 50 days from early April to late May in the whole city. In local areas, if there is no obvious precipitation, temperature drop, strong wind, etc., flying catkins generally affect about 20 days, and the high incidence period is generally about one week. In the flying catkins period, the high incidence period is from 10:00 to 16:00 every day.

According to experts' prediction, the first high incidence period of willow catkins this year will be April 12-18, which will mainly affect the inner city of the Fifth Ring Road. The main species of catkins is Populus tomentosa; The second high incidence period is from late April to early May. The area is urban area and plain area. The main species of catkins are Euramerican poplar, poplar, weeping willow and dry willow; The third high incidence period is in the middle of May, the main area is mountainous area, and the main catkins species are some Euramerican poplar, which has no obvious impact on the urban area.

In the face of the troubles caused by willow catkins on the lives of some citizens, experts also gave protection suggestions. Personal protection shall be provided when going out. Disposable dust masks, sunglasses, protective glasses, gauze towels, etc. can effectively block flying catkins. Outdoor activities such as outdoor exercise should be carried out in the morning, evening or after the rain. Please close the screen window to avoid flying catkins flying into the room. After going out, you can clean your face with clean water and clean your nose and mouth with normal saline. There are many allergens in spring. Although no research shows that flying catkins can cause allergy, it is recommended that sensitive people should go to the hospital in time to check the allergens if they have allergic symptoms. The general public should pay special attention to fire safety. It is strictly prohibited to throw cigarette ends and ignite flying catkins with open fire.

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