It’s another year of flying catkins. The flying willow catkins in the whole city is a unique scenery in the spring of northern cities, but it also causes a lot of troubles, which not only increases the number of allergic patients in hospitals, but also brings many fire hazards. Facing Willow flying catkins, what countermeasures does Beijing have?
Impact on public safety and traffic safety
Ms Sun, who lives in Hufang Bridge, Beijing, has a lot of little red dots on her neck and arms these days, which is itchy and uncomfortable. The dermatologist in the hospital told her that she was allergic to flying catkins and advised her to go out less.
Jiang Sanai, director of the forest operation department of the afforestation and Greening Management Department of the State Forestry Administration, told the reporter of Economic Daily that it was the Willow female trees that produced the flying catkins. Yang catkins in Beijing usually occur in the middle of April, and they usually occur from the end of April to the beginning of May, which will last for about two weeks. Fly catkin is a derivative of willow seeds, which belongs to the natural phenomenon of Willow reproduction. However, when the concentration in the air is high, it will have a certain impact on people’s lives.
Willow catkins mainly occur in northern areas such as Beijing, and the harm is mainly manifested in three aspects: first, it harms the health of citizens. Flying catkins are easy to fly into citizens’ eyes and nostrils, causing skin allergy among allergic people and aggravating respiratory diseases such as asthma and chronic bronchitis. The second is to affect traffic safety and public safety. Flying wadding often blocks the car water tank cooling fin, which causes the boiler to turn off, and also blocks the sight of pedestrians and vehicles. Flying catkins can easily cause fire when exposed to open fire. Willow flying catkins are in the northern dry season, fire danger class high. If the fire is not properly controlled, it will easily lead to fire.
Two days on April 28 this year and 29th, Beijing fire department received 346 forest fires caused by Yang Catkins and miscellaneous weeds. Thirdly, flying batting will hinder the operation of production equipment, affect the accuracy of Precision Instrument measurement, and interfere with industrial production and scientific research activities.
“In addition to being allergic to willow catkins, some sensitive people are actually allergic to pollen in spring, which may be a comprehensive reaction, but pollen is not as conspicuous as willow catkins, therefore, people blame Yang catkin for many allergic reactions.” Jiang Sanai said.
Contribution is greater than harm, and it should not be cut off
Willow trees in northern cities such as Beijing were mainly planted in the 1960 s and 1970 s. At that time, Greening was still in its initial stage, with limited investment and relatively few tree species to choose. Willow has strong adaptability, easy reproduction and survival, fast growth speed and low maintenance cost. It has become the main tree species for greening northern cities and has made great contributions to increasing the amount of urban green and improving the ecological environment. According to the general survey of Beijing’s landscaping department, there are 2 million willow trees a female plant in the built-up area of Beijing, accounting for 5.4% of the total 37 million trees in landscaping. Nowadays, these willow trees have entered the mature stage, so the amount of flying batting is relatively large.
Some netizens suggested that a female plant of the willows that produced flying catkins should be cut off. In this regard, Shen Guozhen, an academician of the Chinese Academy of Engineering, told the reporter that the ecological contribution of willow trees is far greater than the harm of flying catkins, and the control of flying catkins of Willow must not be cut off. At present, there are a large number of willow species in northern cities such as Beijing, and most of them have formed Big Trees. If these trees are removed in large quantities, the urban environmental quality will deteriorate sharply. Poplar and willow have many advantages, such as rich varieties, wide ecological adaptability, strong resistance and vitality, fast growth speed, easy reproduction, tall tree body, beautiful tree shape, good shading effect, etc, it is widely used in urban greening, farmland shelterbelt construction, surrounding greening, road and bank greening, etc. In addition to good landscape effect, willow trees also have remarkable ecological functions such as oxygen release and carbon fixation, cooling and humidification, bacteria reduction and sterilization, absorption of toxic and harmful substances, etc. Poplar and willow have remarkable ability to resist air pollution, and have strong resistance to harmful gases, particles and heavy metals such as sulfur dioxide, chlorine, hydrogen fluoride, etc, it is an excellent anti-pollution tree species for urban landscaping, and is superior to Sophora japonica and Platycladus orientalis in some aspects of anti-air pollution. A poplar with a breast diameter of 20cm can absorb 172 kilograms of carbon dioxide a year, release 125 kilograms of oxygen and retain 16 kilograms of dust. A willow with a breast diameter of 20cm can absorb 281kg of carbon dioxide a year, release 204kg of oxygen and retain 36kg of dust.
As for the suggestion that some citizens on the Internet replace willows with French sycamore, ginkgo and other tree species, experts replied that French Sycamore was named Platanus Platanus, and the flying hair of fruits also easily caused allergy to sensitive people; Ginkgo sprouted late, the deciduous leaves are early and the Green period is short, and the ecological effect is far less than that of Willow. Moreover, compared with these two trees, willow trees are more “solid” and grow better. Nothing is perfect, so is the tree. Experts call on the general public to have more tolerance and understanding of willow trees.
It requires patience to cure the disease, and strive to prevent it from becoming a disaster after 3 years.
The public’s complaints about Yang catkin have always existed. Why haven’t they managed well for so many years?
Yang Zhihua, director of urban greening department of Beijing Municipal Bureau of landscaping and Greening, said that in recent years, Beijing municipal landscaping management department has attached great importance to the problem of Willow flying batting, and has made great efforts to explore the best solution to control Willow flying batting through special research and demonstration research. The following methods are mainly studied and applied:
First, update Willow a female plant. Transform and renew existing stands, eliminate a female plant of Willow, and plant male willow plants or other native tree species. This is the most direct and effective method to control the flying catkins of Willow. However, at present, the number of Willow a female plant in Beijing is very large. Changing tree species requires not only a lot of manpower, material resources and financial resources, useful quantity cutting quota is also needed, so it has not been rolled out in a large area.
The second is injection of flower bud inhibitor. By injecting flower bud inhibitor into trunk, the differentiation of flower bud and the formation of flower buds are inhibited, and the production of floc is controlled. This method needs to be repeated every year, with high cost and easy to cause poplar rot. Up to now, it has only been applied and popularized in key parts and areas such as Fengtai, Shijingshan, Haidian, Chaoyang, Shunyi and Changping.
The third is to remove female poplar flowers. Spraying biological agents to promote the early shedding of female poplar flowers and control the production of flying batting. This method has strict requirements on the application time and application technology: the application reduces the prevention and control effect too early, causes drug damage too late, and even affects the normal growth of trees in serious cases. Therefore, this method has not been widely applied.
Fourth, Willow High grafting. Cut off Willow a female plant crown, and graft male scions at a high level to control the production of fly Catkins. This method has high requirements on grafting technology and high maintenance cost after grafting. In fact, it is only tested in a small range.
“Generally speaking, the technical methods such as injection of flower bud inhibitor, sparse removal of Poplar female flower, Willow High grafting and so on have certain effects in the actual popularization and application process, but all have high costs, it is difficult to implement and harms the normal growth of trees. Especially in Beijing and other regions, the existing base number of Willow a female plant is large. It is difficult to complete the transformation of Willow a female plant in a short period of time and achieve obvious governance effects. It requires a combination of measures, length and length, and gradual reduction. Now the urban and even suburban areas of Beijing are no longer the problem of lack of green, but how to make the greening match better. The diversity of ecosystem and tree species allocation should be maintained, which is the most fundamental way to solve the problem of willow catkins.” Jiang Sanai said.
Beijing plans to “cure the symptoms” by pruning the crown, chemical flower suppression and other methods, and “cure the root causes” by means of source control, gradual replacement, thinning over dense forest land, etc., and strive to basically control the Willow flying bamboo by 2020, implement the problem of non-disaster.
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is another year of flying batting. The flying willow catkins in the whole city is a unique scenery in the spring of northern cities, but it also causes a lot of troubles, which not only increases the number of allergic patients in hospitals, but also brings many fire hazards. In the face of Willow flying catkins, what should Beijing do