Catkin control efforts have begun across Beijing as poplar and willow catkins drift through urban roads. Specifically, the flying period will last until late May, approximately 50 days. The first peak will arrive around mid-April. The Beijing Municipal Forestry and Parks Bureau announced the measures on Monday.
Beijing has deployed various intelligent control technologies for mature female poplar and willow trees that cannot replace immediately. Jiang Yingshu, director of the science and technology division of the Beijing Municipal Forestry and Parks Bureau, explained the approach to the Global Times. A coagulant from the Beijing Academy of Forestry and Landscape Architecture forms an ecological film on the crown surface. This film bonds and shrinks the catkins before they burst. Consequently, a single spray reduces catkin emissions from a single tree by more than two-thirds.
The coagulant is non-toxic, harmless, and environmentally friendly. It works with high-pressure fog cannons and drones. Rain and sunlight degrade the coagulant naturally without affecting tree growth. Thus, these catkin control efforts prioritize environmental safety alongside effectiveness.
A portable catkin absorber has also entered full use this season. The equipment enables precise directional absorption without removing other debris. It efficiently cleans fallen catkins in residential areas and road corners where manual cleaning proves difficult. Moreover, the absorber also helps eliminate fire hazards from catkin accumulation.
Beijing has built a real-time monitoring and forecasting platform for catkins. The city has set up over 100 special monitoring points across the metropolitan area. These points track the whole-cycle development of female poplar and willow inflorescences. As a result, the catkin control efforts rely on this data to time interventions precisely.
Willows and poplars were widely planted in the 1960s and 1970s to curb sandstorms. Willows have the longest green period among broadleaf trees used in urban greening. Without them, Beijing’s green season would shorten by around 30 days. Poplars grow 20 to 30 meters tall. Similarly, without them, Beijing’s green skyline would drop 5 to 10 meters.
The city has collected nearly 400 poplar and willow germplasm resources with little or no catkins. Scientists have selected 16 superior varieties. Furthermore, a tissue culture breakthrough enables propagation of about 1 million seedlings within 2 to 3 years. These catkin control efforts include long-term genetic solutions.
For the May Day holiday, Beijing will deploy more workers and increase cleaning frequency in parks, scenic spots, shopping malls, and transport hubs. No research suggests catkins cause allergies, though they may trigger discomfort in sensitive individuals. Therefore, officials advise taking protective measures when going outside. The catkin control efforts will continue through the end of May.
