Disease destroying pine forests in Guangdong
If not stopped, a tiny parasite that is killing tens of thousands of pine trees in Guangdong may cause huge environmental problems.
Lumberjacks in the province are cutting down trees to stay ahead of nematodiasis or "forest cancer," a disease that has killed more than 10,000 pine trees at the South China Botanical Garden.
Nematodiasis, caused by a contagious parasite carried by beetles common in forest areas.
The South China Botanical Garden is just one of the many areas where nematodiasis has been found in the province..
According to a provincial forestry official yesterday, the disease is threatening the southern province. It is usually found in northern parts of the country or outside China.
"Nematodiasis has been found in many cities in the province," said Lin Duping, director of the Tree Disease Prevention and Control Department under the Guangdong Provincial Forestry Bureau.
"And we actually face many difficulties in eradicating the disease, one of the three major forest diseases in the world," Lin told China Daily.
There is no quick and easy cure for the disease.
In addition to widespread disinfections and cutting down dead trees, Lin said his bureau is also planning to ask forestry departments to raise a species of bee that can help cope with the disease.
Nematodiasis is caused by a tiny nematode parasite. The bees can kill the beetles that host the parasite and curb the spread of the disease.
Lin also called for tighter controls on imported lumber to prevent nematodiasis from further entering the country.
Wang Weiwen, an official from the Guangzhou Municipal Bureau of Forestry Industry, said nematodiasis has been found in other pine forest areas in Guangzhou. To date, it may have affected more than 86,666 hectares of pine trees or one-third of the city's total forest areas.
Affected by the scourge, many pine trees have withered, Wang said.
A pine tree can die about 40 days after it contracts the disease.
And all Guangzhou's pine trees will die unless effective measure are taken quickly, Wang said.
The death of the pine trees could result in serious soil erosion and pollute the upper reaches of the Liuxi River, which provides drinking water for more than 10 million residents, Lin said.
Located in Conghua, a suburban city of Guangzhou, the upper Liuxi River winds through one of the major pine forests in the metropolis.
In Guangzhou alone, the economic losses caused by the disaster have topped 50 million yuan (US$6 million) annually.
The Guangzhou municipal government has invested more than 10 million yuan (US$1.2 million) to fight nematodiasis in the past three years.
Nematodiasis was first found in Guangzhou four years ago. And the disease has spread to cover more than 963 hectares in the city, Wang said.
In addition to the suburban city of Conghua, nematodiasis has also been found in Guangzhou's Huadu and Panyu districts.
Lin Duping said Guangdong's nematodiasis was first found in the Shenzhen Special Economic Zone in 1988.
The disease is believed to have come from overseas, Lin said.
In 1995, nematodiasis spread to neighbouring cities of Huizhou and Dongguan in the eastern part of the prosperous Pearl River Delta region.
By the end of last month, the disease was detected in more than 21,466 hectares of pine forests in the entire province.
Guangdong Province has more than 4.13 million hectares of pine forests.
The province is losing between 5 billion yuan (US$600 million) and 10 billion yuan (US$1.2 billion) from nematodiasis.