Like most blizzards, it begins with just a few white wisps swirling about. Gradually the volume increases and the stuff starts to accumulate on the ground. During the heaviest downfalls the air is so thick with it as to impair visibility. But this is no winter scene. It is what happens every April across much of northern China, when poplar trees start giving off their cotton-like seed-pods.

     The phenomenon has already begun in Beijing. On April 8th an eddy of fluff balls wafted around the American treasury secretary, Janet Yellen, as she held a press conference in an embassy garden.

     To call this a nuisance is an understatement. In many people the fluff triggers allergies, asthma and other respiratory problems. Experts say the white balls—produced by the trees’ catkins—are not themselves allergenic, but that they distribute irritating pollen.

      They also clog rain gutters, drain pipes and car radiators. Worse, they pose a fire hazard. Officials have warned that the fuzz balls have a low ignition point and called for extreme caution on the part of smokers, welders or anyone inclined to burn them “out of curiosity”.

       China’s catkin problem is the unintended consequence of an old effort to improve the environment. Intensive tree planting began in the 1950s with the aim of ending the scourge of sandstorms caused by winds sweeping out of barren areas. The trees were also meant to firm up the soil and slow desertification. Poplar trees, along with willows, were selected because they are cheap, fast-growing and drought-resistant.

    In some ways the plan worked. Today sandstorms are less severe and the threat of desertification has faded. But the annual onslaught from catkins is another legacy. Female trees are the cotton-ball culprits. There are millions of them (poplar and willow) in Beijing alone.

    Authorities have sought to mitigate the mess. The simplest way is to spray water on the trees, turning the fluffy flyers into damp squibs. More advanced solutions involve “birth control”, or injecting female trees with chemicals that suppress catkin production. Another option is “gender-reassignment surgery”, in which branches on female trees are cut and replaced with male grafts. 

   But experts say that these efforts will take time. The good news is that the flurries of poplar fluff will only last for a few more weeks. The bad news is that wafts of willow fluff will then begin. 

From: https://www.economist.com/china/2024/04/18/examining-thefluff-that-frustrates-northern-china