How long will humans continue to be tortured by these bad habits that cannot be changed even by “sex change” or injections?

Spring is here, and it’s here again… the season when flying snow rules the world. This special spring season of snow always makes people love and hate it – love its beauty, but hate it even more when it covers people’s faces and mouths, causing them to sneeze like crazy, inflame their eyes, and cause allergies.

So where does this vigorous flying catkins that lasts for several months come from?

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01

Willow Tree

Creating the Northern Flying Catkins Season

Beijing is probably the typical representative of victims of flying catkins in North China. From April to mid-May every year, you can not only see flying catkins with a diameter of dozens of centimeters rolling slowly on the ground on the roads in Beijing, but also see the lawns covered with flying catkins into a magnificent white spectacle. If you are "lucky", when driving through the "hardest hit area" of flying catkins on the ring road, you can even feel a "flying catkins snowstorm" - the roadside trees sway in the strong wind, and they will scatter seemingly endless flying catkins.

I believe that people living in Beijing, whenever they see such a scene, they can't help but ask and sigh: Where do all these catkins come from? It's so annoying!

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Beijing's flying catkins mainly come from poplars and willows that are scattered throughout most of the green belts in the city. Every spring, they enter the breeding season and begin to spread seeds desperately, and the nightmare flying catkin season begins. Beijing's poplar catkins mainly come from white poplars , and willow catkins come from Salix matsudana . Generally speaking, the flying catkin season starts with white poplars and ends with Salix matsudana . The main purpose is to create an extra-long flying catkin season for humans.

Flying catkins look like a white and fluffy mass, but they are actually wrapped with seeds from poplars and willows. If you are interested, you can pick a piece of flying catkins from your face and peel it carefully, and you will find small seeds wrapped in the white hairs. It turns out that these white hairs are just to help poplars and willows spread their seeds, not to annoy people intentionally. With these catkins, their seeds can fly farther with the wind, and pass on life to farther places.

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However, poplars and willows are fast-growing, cold-resistant, and highly resistant trees . They are planted as street trees on the streets of Beijing, bringing greenery to the city, but also causing some troubles. Poplars and willows may not have "thought" that most of the large number of seeds they produce for reproduction have no chance to fly to fertile soil, but are ruthlessly swept into the trash can by humans.

02

Do all willow trees produce fluff?

Is it possible to prevent them from producing fluff?

Not all poplar and willow trees are the "black hands" behind the catkin problem. In fact, only female trees have catkins . Therefore, people have now found some ways to prevent and solve their catkin problem.

The first method is to directly change the sex of the tree. By grafting male branches onto female trees, the female tree can be transformed into a male tree that does not produce catkins.

The second method is to give the tree "medicine" . You can spray the poplar catkins with medicine before they form flying catkins to make them fall off in advance. You can also inject flying catkin inhibitors into the tree . Precise application of medicine directly inhibits the differentiation of female flowers . Without female flowers or catkins, seeds cannot be formed, and naturally there will be no flying catkins problem.

The catkin inhibitors applied to poplar trees in the park can inhibit the formation of flower buds. Photo by Cui Yinghao

Unfortunately, the above two methods are not simple to operate and cannot achieve 100% suppression, so flying catkins are still reported every year.

As for the third and most effective method, it is to directly replace the trees , either female trees for male trees or tree species. However, it takes time for trees to grow, and it often takes several years to form the same shade effect as before. In addition, the climate in North China is not suitable for all trees to grow, so although it is effective, it is also very difficult.

Moreover, the economic investment in replacing trees is quite high. There are 2 million female poplar and willow trees in Beijing alone, and the planting area of ​​poplars nationwide has reached about 4.9 million hectares. If all of them are replaced, it will be a huge investment. Therefore, the problem of flying catkins is not that no one cares about it, but there is no optimal solution that is efficient and low-cost.

03

Flying Catkins

Not only annoying but also harmful

Whether in the north or south, flying catkins are a common problem. In fact, flying catkins not only bring us sensory discomfort, but also may cause many problems.

1. Itchy

The plant fibers that make up the flying catkins are often very small. In addition to the parts that we can see with our naked eyes, there are many fine fibers floating in the air, which can easily stick to the skin and eyes, or go down the nose and mouth to the mucous membranes, and even irritate our respiratory tract, causing waves of "itching" that make people scratch their ears and cheeks. Generally speaking, if you leave the flying catkins environment and go indoors for a while, the itch will ease.

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2. Causes allergies

Flying catkins are generally composed of seeds, fluff and plant oils, and their components may be allergenic. What's worse is that during the process of floating, falling and floating again, they may pick up pollen, bacteria, fungi and other allergens. If we accidentally come into contact with them, it may cause a strong allergic reaction, such as allergic rhinitis, allergic conjunctivitis, etc. In severe cases, it may also stimulate respiratory diseases such as asthma and chronic bronchitis.

Even if you don't have allergies, the germs carried by catkins can cause inflammation when they come into contact with mucous membranes. Because, during the catkin season, it's best not to go out. If you really have to go out, be sure to wear a mask and goggles, and wash your face and hair in time after returning home to avoid allergies and inflammation .

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3. Cause a fire

There is a lot of vegetable oil in the catkins, which are highly flammable after drying. If a large amount of catkins are piled up and accidentally come into contact with a fire source such as a cigarette butt, it may cause a major fire . In addition, since catkins burn quickly, some bored people will light catkins for fun, which will cause fires.

For example, in 2017, someone was sentenced for lighting burning willow catkins in a resort that was not cleaned up in time, resulting in a large number of vehicles being burned and causing heavy losses.

Some cases can also be found in the online judgment documents where minors, due to poor parental supervision, set willow catkins on fire for fun, which ultimately resulted in serious losses.

In addition, if window screens are not used, catkins may enter the house and accumulate, posing a fire hazard. In places like gas stations and factories, if catkins are not cleaned up in time, the risk of fire will also increase.

Therefore, do not underestimate the tiny willow catkins. If you find them piled up, you should clean them up in time. It should be noted that you should never use simple and crude methods such as burning them to save trouble. The correct way is to spray the catkins to wet them and then clean them up .

4. Causing an accident

If tiny flying catkins enter precision instruments such as computers, they may cause machine failures and affect normal operation. If they fly onto the road and block vision, they may cause traffic accidents.

In short, the flying catkins season is inevitable. Before the big wave of flying catkins arrives, everyone must be prepared and protect themselves.

Author: Hydra Science Author

Reviewer: Wang Kang, Director of the Science Museum of the National Botanical Garden

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