Metro

Debate rages on solutions as tree fluff gets up noses

By Meng Jing (China Daily)
Updated: 2010-05-04 08:00

Fluff is now becoming a nuisance as the temperature rises in the city. YANG WEI / FOR China Daily

A two-week-long invasion of fluff from millions of willow and poplar trees in Beijing kicked off during May Day holiday as the city's temperature jumped past springtime.

Catkin, from blooming willows and poplars, has once again emerged as a health annoyance for residents suffering from allergies and respiratory diseases.

Forestry authorities launched their annual war against the fuzzy trees in early April in some populated areas, but have suggested a large-scale catkin-free management system is unlikely in the near future and are asking the public to embrace the natural phenomenon with a tolerant attitude.

Once the average temperature reaches 15 C, "female" willow and poplar trees begin their blossoming period, which leads to the production of catkins. The snowy-looking tree blossom usually arrives in Beijing in late April, but unusually cold weather this spring postponed the intense catkin season until the May Day holiday.

Official statistics from the Beijing Municipal Bureau of Landscape and Forestry show the city has 1.9 million poplars and 1.1 million willows, out of which 30 to 40 percent are "female".

Efforts have been made by the bureau to relieve the unpleasant experience since 2003. Chemical injections and tree sex changes are the two approaches to tackle the fluff. The former option is mostly used in poplars while the latter is more suitable to willows.

According to the Beijing Institute of Landscape Science, as many as 800 willows and 50,000 poplars have received chemical injections and sex change surgeries so far.

Che Shaochen, an engineer from the institute, said his center has recently received frequent phone calls concerning catkin-free solutions.

"When some residents cannot open their window because of the flying catkins, they call us for help," he said.

Che said that apart from causing health problems, the cotton-ball-like clusters are very difficult for street sweepers to remove and can be hazardous because of their flammability.

Che, who heads the research team on the chemical injection against catkins, revealed that the intention of the jab is to stop trees from blossoming so they cannot produce catkins.

Compared with tree sex changes, which involve pruning high branches and splicing male branches onto them, chemical injections are far easier to undertake, he said.

"There are fewer than 20 professionals in Beijing who can manage a tree sex change, but anyone can perform a chemical injection with a little training," Che told METRO.

The tree expert said he is performing research to lower the price of a chemical injection from the 10-yuan per jab. A tree sex change operation costs around 100 yuan.

However, money is not the only factor to consider for landscape authorities, since chemical injections need to be done annually and a full year in advance.

Jia Yu, a researcher from Institute of Botany with the Chinese Academy of Sciences, said a string of injections might damage the trees.

"Chemical injections have only been on the market for three years. No one knows what the long-term side effects might be," Jia said.

Wang Jianjun, vice-director of the science and technology department with the bureau, said the willows and poplars have contributed to Beijing's landscape.

"The city grew lots of willow and poplar trees in 1980s, because no other trees could grow as fast. However, as the city grew, so too did the number of complaints about the fluff," Wang said.

"It is a natural phenomenon; we cannot just cut them down because they have blossom," he said.

He believed it is wrong to change the nature of plants and hoped more people will accept a short-term inconvenience.

China Daily

(China Daily 05/04/2010 page25)