TAIPEI (Taiwan News) — Chiayi County Agriculture Department official Li Chiu-ying (李秋瑩) on Tuesday urged the public to participate in the Forestry and Nature Conservation Agency Chiayi Branch's bittervine removal program to help curb the spread of the invasive species.
Li said bittervine should be removed before its flowering season from August to September to help prevent its spread, per CNA. The removal program runs from Feb. 23 through Dec. 18 and pays participants NT$5 (US$0.16) per kilogram of harvested bittervine.
The department recommends removing bittervine by hand because using brush cutters or other machinery can inadvertently spread the plant.
Li said individuals and community development associations registered with the interior ministry may participate by bringing harvested bittervine, packed in large plastic bags, to ranger stations designated by the Chiayi Branch.
According to the Chiayi Branch, harvested bittervine is accepted every Monday, Wednesday and Friday from 9 a.m. to noon and from 1 p.m. to 4 p.m. at the Guanziling, Yujing and Chukou ranger stations. Participants must present identification and complete an application form.
The Forestry and Nature Conservation Agency has designated Aug. 15 to Sept. 15 as bittervine Prevention Month. While the agency pays a base rate of NT$5 per kilogram, local governments may offer additional incentives. Taoyuan, for example, provided an extra NT$3 per kilogram, per Liberty Times.
Although the exact date bittervine was introduced to Taiwan is unknown, it was originally imported for its medicinal properties and other uses, per Harvest. The earliest known specimen collected in Taiwan dates to 1986. By 2002, the vine had spread to about 56,848 hectares across the country.
By 2023, removal efforts had reduced the infested area to about 4,000 hectares, per Liberty Times.
Bittervine grows by climbing over other plants and forming dense blankets that block sunlight, preventing its host from carrying out photosynthesis. The process often kills the host plant and reduces biodiversity in affected areas.
Association of Taiwan Forest Restoration CEO Tsai Chih-hao (蔡智豪) said healthy forests are generally resistant to bittervine, while abandoned farmland and forests disturbed by human activity provide ideal conditions for its growth, per Our Island. He said restoring abandoned farmland to agricultural use and rehabilitating Taiwan's native forests would help limit the vine's spread.
Researchers have also explored ways to reuse harvested bittervine. In addition to incineration, the vine can be processed through wood vinegar extraction to produce cleaning products. The remaining carbonized material can be used to reduce soil acidity, potentially improving soil quality.
