Poplar Catkin
Poplar is one of the main tree species for afforestation in China. Every spring, when most of the poplars reach sexual maturity, seeds and white catkins fly through the air. As shown in the photo, catkins are visible under street lamps. Although it is not toxic, it can cause discomfort when it flies into pedestrians' eyes or nostrils. At the same time, poplar catkin is a kind of combustible material, and has the characteristics of dry, and low ignition point, it is easy to happen combustion accidents, increase its harmfulness. Chang et al. (2019) found that poplar catkins float everywhere, not only causing environmental pollution, but also causing pathogenic bacteria. Dense poplar catkins can block the sight of pedestrians and vehicles, and often block the radiator of car water tank, thus affecting traffic safety. (Beijing, 13 May 2022)
Empty Site
Due to the epidemic in Beijing, a temporary tent will be set up outdoors in some communities next to apartments, so that medical staff can help residents in the community to conduct frequent nucleic acid tests to ensure good health. However, nucleic acid testing in the outdoors was temporarily suspended due to the arrival of spring catkins. If poplar catkins fly into pedestrians' eyes and nostrils, making people feel uncomfortable, people with allergies contact or inhalation of catkins, easy to cause runny nose, sneezing, shortness of breath, skin contact easy to cause itching, swelling and even peeling skin, contact with eyes easy to appear conjunctivitis and other symptoms (Chang et al. 2019, p.1). So the outdoor nucleic acid testing site is empty. (Beijing, 13 May 2022)
Artificial Injection
In some places of China, artificial injection is used to solve the problem of poplar catkins. The agents used for injection are some floating catkins inhibitors, which can prevent the problem of poplar catkins to a certain extent. Injections can only solve local problems, but can not be used in a large area or a wide range at present. First, there is a time limit for injection. In Beijing, China, the time of injection is from late May to early June every year. During this period, injection is effective. Second, the cost of injection is relatively high. The cost is about 40 yuan per tree, excluding labor costs. Therefore, this method is not a permanent solution. (Beijing, 15 May 2022)
Manual Spraying
In some places, spraying tree crowns with soluble collagen can prevent catkin problems, which can be effective in the field if sprayed in time. Water use is very large, each poplar needs 50 to 100 kilograms of water, the cost of each tree protein spray is 5 yuan. Poplars sprayed with a water gun every day, speed up the flocculant setting the flocculant keeps the catkins down, increasing the moisture in the air, reducing the likelihood that the catkins will spread, but that's too human-intensive and inefficient. At the same time, through the time limit, only in poplar production flocculation. Although the method is time-consuming, it can control the harm of poplar catkin disease to a certain extent. (Beijing, 17 May 2022)
Automatic Spraying
Using water pipes to spray poplar drugs, this treatment measure can be said to be the most simple and effective is also the latest developed a method, the application of new treatment of poplar flocculant, combined with poplar disease and insect pest control comprehensive management, mainly suitable for large area of poplar forests in northern China. The advantage of using water pipe spray medicine prevention and control is time-saving and labor-saving, and has the characteristics of no pollution, the effect is good. But water pipes are prone to crack, and in the road sometimes very affecting the passage of pedestrians. (Beijing, 17 May 2022)
Replace the Trees
Liu et al. (2021) believe that poplars are abundant and widely distributed in China, which can prevent sandstorms and bring good economic and ecological benefits. General tree species do not have the adaptability and resistance of poplar. How short is the growing period of poplar, in line with the characteristics of current economic development and ecological construction. Other tree species and poplars are more expensive than saplings and have lower survival rates. Poplars are too tall to be harvested on a large scale in a short time, so small-scale felling is carried out in areas where catkins are common and poplars are replaced with other species. (Beijing, 21 May 2022)
Daily Cleaning
Cleaning workers have one more task in the spring, which is to observe and clean up catkins. Each community's cleaning personnel or the management personnel dispatched by the parking lot management department will timely clean up the accumulation of poplar catkins on the ground, to prevent the occurrence of fire, igniting vehicles, resulting in further damage. The cleaner in the photo is making sure that there is no accumulation of catkins near each car to prevent it from building up in the engine compartment and causing a fire. (Beijing, 25 May 2022)
Collect Flammable goods
Due to its flammable nature and dry spring, catkins are also prone to fires due to improper disposal. The workers in the photo are collecting boxes and inflammable items that are particularly prone to fire. "If the Yang catkin has been on fire encountered carton consequences will be unimaginable. " Said a worker. (Beijing, 1 June 2022)
Turn in combustible goods
There are many electric bikes parked under apartment buildings because of the centralized charging facilities for electric bikes. After the call of the community, the residents will also be sorted out the waste cartons correctly handed in, so as not to throw away, randomly thrown in places that are also prone to fire. Staff also remind residents to pay attention to timely cleaning combustible, eliminate hidden dangers. (Beijing, 1 June 2022)
Disinfection of Public
The entrance of the subway station is also a very important place for governance. During the morning and evening rush hours, when there is a large flow of people, bacterial transmission is rampant. "To ensure that the bacteria carried by the catkins do not spread to each other, we started cleaning and disinfecting the catkins all day from 5 am." Said a cleaner. (Beijing, 3 June 2022)
