LCQ3: Management and removal of Leucaena leucocephala
*****************************************************
Question:
I raised a question on tree management in 2023, and the Government advised at the time that Leucaena leucocephala would be removed in the course of regular vegetation management work. However, members of the public have reflected that insufficient attention is still being given to the management of Leucaena leucocephala. In this connection, will the Government inform this Council:
(1) whether it will adopt a more proactive approach in taking forward interdepartmental efforts to remove Leucaena leucocephala, including setting work targets, identifying priority locations for removal and establishing ongoing removal arrangements, and regularly publishing progress updates with a view to curbing its spread; if so, of the details and timetable; if not, the reasons for that;
(2) whether it will incorporate guidelines and departmental operational requirements for controlling Leucaena leucocephala into the Guidelines on Tree Transplanting, including, having regard to its growth and propagation situation in Hong Kong, stipulating requirements for the early removal of seedlings and regrowth before flowering and seed setting, conducting regular follow-up inspections, and preventing seed dispersal, and whether such requirements will be incorporated into outsourced contracts and acceptance criteria; if so, of the details and timetable; if not, the reasons for that; and
(3) whether it will strengthen public education on identifying Leucaena leucocephala, its ecological impacts and control measures, and collaborate with schools, district organisations and environmental groups to implement volunteer participation programmes enabling members of the public to take part in monitoring and reporting activities and, under professional guidance, remove Leucaena leucocephala seedlings; if so, of the specific arrangements and timetable; if not, the reasons for that?
Reply:
President,
Leucaena leucocephala (White Popinac) is an invasive alien species and is highly tenacious. It impedes the natural succession of native species, and poses safety hazards with its brittle branches that are prone to breaking or falling in strong winds. Therefore, government departments remove Leucaena leucocephala in the course of regular vegetation management to safeguard public safety.
The replies to the respective parts of the question are as follows:
(1) and (2) Tree management departments are required to carry out tree and vegetation maintenance in accordance with the Technical Circular issued by the Development Bureau (DEVB) on Tree Preservation and the relevant guidelines. Before the wet season each year and after typhoons, tree management departments are required to inspect trees in areas with high pedestrian or vehicular traffic, conduct risk assessments in accordance with the guidelines, and take appropriate mitigation measures for trees posing risks, in order to safeguard public safety. If Leucaena leucocephala is identified during inspections, departments will promptly arrange for its removal within two to three weeks. If it is located on the roadside or along an expressway, the removal may take longer because temporary traffic-diversion arrangements are required. Nevertheless, the principle remains that removal should be carried out as soon as practicable once identified.
In addition, departments conduct regular vegetation maintenance work. For example, the Highways Department inspects slopes and planting areas under its management regularly - generally every six months - and carries out vegetation maintenance, including the removal of Leucaena leucocephala. The Leisure and Cultural Services Department also carries out similar regular vegetation maintenance for amenity areas and public open spaces under its management. The relevant departments' outsourced contracts also require contractors, when carrying out vegetation maintenance, to remove undesirable plant species, including Leucaena leucocephala, so as to ensure healthy growth of plants within the planting areas.
The above-mentioned Technical Circular issued by the DEVB and the relevant guidelines also stipulate that, when government departments come across undesirable tree species, e.g. Leucaena leucocephala, during works projects or routine maintenance, they may remove such species directly without transplanting, compensatory planting, or prior approval, so as to enable the relevant clearance work to be carried out more efficiently. This also helps curb the further spread of such undesirable species in Hong Kong.
Since Leucaena leucocephala is highly tenacious, it can hardly be eradicated by way of one-off large-scale clearance. Therefore, in accordance with the aforementioned Technical Circular and guidelines, departments will promptly arrange for the removal of Leucaena leucocephala whenever it is found, without waiting for it to reach a specific growth stage. Ongoing efforts to remove stumps and seedlings can gradually deplete the Leucaena leucocephala seed bank in the soil and curb its further spread. Where appropriate, departments will replant the affected areas to establish stable vegetation cover and reduce the likelihood of re-emergence of Leucaena leucocephala.
To further enhance the efficiency of tree management, the Government is actively exploring the use of artificial intelligence (AI) technology to help identify Leucaena leucocephala along roadsides in support of vegetation maintenance work. Through image analysis and intelligent identification systems, the technology can help departments grasp more quickly the distribution of Leucaena leucocephala and arrange for subsequent clearance work. We will continue to explore the use of innovative technology to enable more proactive and systematic management to enhance tree maintenance.
(3) On the front of public education, the DEVB from time to time disseminates information on greening and tree maintenance to the public through various channels. The television documentary "The Pulse of Hong Kong Forests" launched by the DEVB and Radio Television Hong Kong in end-2025, which mentioned the handling of Leucaena leucocephala, is one of the examples. The DEVB will continue to work in collaboration with different departments to enhance public and industry awareness of Leucaena leucocephala through a variety of means, including social media posts, school learning materials, public forums, webinars, newsletters, and workshops.
As Leucaena leucocephala often grows along roadsides, on slopes, or on wasteland, we consider it preferable for removal work to be carried out by professional personnel or contractors with the relevant knowledge and appropriate equipment. Members of the public are generally not advised to take part in clearance work. If members of the public spot Leucaena leucocephala, they may report it to the relevant department or through the 1823 hotline, we will take note of the reports and follow up promptly.
Ends/Wednesday, November 11, 2026
Issued at HKT 17:12
Issued at HKT 17:12
NNNN