Frequently Asked Questions

For years, trees are highly valued by the people of Hong Kong who love and care about them. The Greening, Landscape and Tree Management Section of the Development Bureau (DEVB) has been working to foster a culture of love of plants and trees through diversified community participation activities, and by encouraging public participation in tree risk assessment and enhancing public education and community surveillance on the health of the trees, in order to ensure public safety. To allay the worries of the public and foster a better understanding of the Government's tree management policies, we have compiled a list of common concerns and responses as follows:

General Situation

Q1: What are the duties of the Tree Management Office (TMO)?
A1: The Government adopts an "integrated approach" for the management of trees. Under this approach, the different departments responsible for the maintenance of an area or a facility are also responsible for the maintenance of trees there, so as to optimise the use of resources. The duties of the TMO are to co-ordinate the tree management work of different departments, enhance public education and community involvement, provide regular training, promulgate best practices, conduct relevant researches and resolve complex cases, etc., so as to facilitate the departments to manage the trees under their care in a more effective and professional manner.
Q2: How many trees have been planted by the Government in recent years?
A2: Please visit the Planting Records.
Q3: Do the TMO staff have the expertise to carry out their duties?
A3: Currently (February 2016), the TMO has a total of 17 posts responsible for tree management. Most of these post-holders possess international professional qualifications in arboriculture, such as the International Society of Arboriculture (ISA) Certified Municipal Specialist, ISA Certified Tree Risk Assessor, ISA Certified Arborist, holder of Certificate in Professional Tree Inspection (LANTRA Awards UK) or honorary bachelor degree in arboriculture, etc. One of the post-holders has a doctoral degree in arboriculture.
Q4: Do the tree risk assessment methods adopted by the TMO comply with the international standards?
A4: We developed our tree risk assessment methods by mainly referring to the guidelines of the ISA, the U.S. Department of Agriculture and the relevant professions in the U.K. Thus, we follow the commonly-used international standards.
Q5: What would the DEVB do to enhance professionalism of management staff?
A5: The Training Committee established by the DEVB drew up relevant training and manpower development strategies for Government departments in order to ensure that all relevant departments would have competent staff to duly perform managerial, supervisory and frontline duties. The TMO will continue to organise for Government personnel responsible for tree management work training courses relating to the tree management such as tree risk management, tree identification, common tree problems, pests and diseases control, proper tree care measures, tree protection during construction works, etc. In addition, the TMO will also work with the local training institutions to provide more appropriate training opportunities for relevant government personnel, consultants and contractor employees.
Q6: What would the Government do to ensure that the tree risk assessment is effective in preventing injury arising from tree failure?
A6: Like other living things, trees undergo the life cycle of growth, ageing, sickness and death. Tree risk assessment allows departments to duly manage potential tree risk. Much effort is devoted to minimizing risk of tree failure at areas with high pedestrian and traffic flow. Notwithstanding that the health of a tree is subject to change over time and weather conditions (especially during inclement weather), we give our best endeavour at tree risk management.
Q7: Has the TMO made public details of the problematic trees?
A7: The publicly accessible Tree Register was established in July 2010. It contains such information as the distribution and conditions of and risk mitigation measures for important trees (Old and Valuable Trees (OVTs) and stonewall trees) and problematic trees that require close monitoring. The Tree Register is updated regularly. Departmental inspection officers assess the health and structural conditions of the trees on the Register and work out remedial actions and inspection timeframes (from several days to several months); while the TMO reviews the relevant risk assessment reports and conducts site inspections. Public can access the Tree Register website.
Q8: How would the Government ensure the performance standard of horticultural contractors?

The Government attaches much importance to the performance of horticultural contractors, and diligently monitors their work performance in accordance with the service contracts.

The Government states clearly all necessary work requirements for compliance in horticultural and tree management contracts. If the performance of a contractor cannot meet these service standards, departments concerned will, depending on the situation and according to the contract, take action against the contractor.

Meanwhile, the TMO has already issued guidelines on proper pruning practices and irregularities that should be avoided.

Q9: What are the procedures for tree removal (tree transplanting and/or tree felling) on private or leased land?

If the tree concerned is located on leased land with tree preservation clause(s), removal (inclusive of tree transplanting and/or tree felling) of such tree is controlled by the relevant lease clauses.

Prior to any tree removal, the lot owner or his/her representative shall submit a tree removal application to the respective District Lands Office of the Lands Department for approval. The application shall include tree information, reasons of tree removal and compensatory planting proposals. No tree removal is allowed until written approval is obtained from the Lands Department.

For details and enquiries regarding tree removal applications, please refer to Lands Administration Office"s Practice Note Issue No. 7/2007 or contact the respective District Lands Office of the Lands Department.

Q10: Why doesn't the Government put the fallen trees or dead branches collected into the planters nearby for use as soil cover or compost, but send them to the landfills instead?

Due care must be taken when using broken branches or tree trunks as mulch or compost. As these broken branches and tree trunks may be infected with diseases, using them as mulch may spread the diseases to other plants.

As a typhoon hits Hong Kong, a huge number of branches or trees may be damaged in a short time. The departments concerned will first clear or remove the trees that may endanger our lives or property. Then they will clear the trees that block the traffic in order to open up major highways and carriageways at the earliest instance to minimise the impacts on the public. Therefore, it is not practical to require the departments to inspect a huge quantity of fallen trees and broken branches to identify pest and disease in a short period of time right after the typhoon.

However, for the routine vegetation maintenance work including grass cutting, pruning in which disease parts are not involved, departments are encouraged to reuse and recycle yard waste.

Q11: Has the Government considered other more environmentally-friendly ways to process the dead plants in order to relieve the pressure on the landfills?

Within the country park areas, the Agriculture, Fisheries and Conservation Department will turn plant waste into country park facilities, or stack them up at suitable locations to create suitable habitats for wildlife, and allow natural decomposition to occur.

As to the handling of plant waste, the departments concerned are studying how to make effective use of the compost or organic mulch as fertilisers in order to recycle plant waste. The DEVB will support the Environment Bureau"s work on the treatment of plant waste. The DEVB has also worked in conjunction with the tree management departments to launch a pilot programme with requirements to enhancing sustainability, such as the use of local compost and recycling felled trees, in a number of horticultural maintenance works. The Guidelines on Yard Waste Reduction and Treatment can be available here.

Q12: What should a private property management company do if poisonous plants are found inside a private property?

In general, planting of plants with known toxicity is not recommended in areas easily accessible to the public. If poisonous plants are already planted within a property, warning signs should be erected next to those plants to discourage the public and vegetation management workers from direct contact with the poisonous parts of the plants. When opportunities arise, the property management company should consider replacing the poisonous plants with non-toxic ones for public safety's sake.

Brown Root Rot (BRR) Disease

Q13: Recently, several OVTs have been found to be infected with BRR disease. Is there extensive infection in the territory? Does the TMO have any ways and means to tackle it? Is massive tree felling necessary to contain the spread of the disease?
A13: Although there is as yet any effective way to cure BRR disease, we have some knowledge of its modes of transmission. The disease is caused by fungi and is spread mainly through root contact or infected soil, and the likelihood of transmission by wind dispersal is low. Hence, the way to contain the infection is to properly handle infected wood tissues and soil. For serious infection cases, we will remove the infected trees and the debris together with the soil and arrange for disposal at landfills. According to related studies, application of fungicide to trees suffering mild infection is useful to a certain extent. Apart from applying fungicide, trenches will also be dug to separate the infected trees from healthy ones, with plastic or metal planks inserted to block the pathogen. Departments concerned will also arrange frequent inspections of trees in the infected area.
Q14: Are the frontline staff qualified to treat trees infected with BRR disease?

To enhance the knowledge of frontline and management staff on the control of the pests and diseases of plants and trees, the TMO has organised a number of courses on their control, including the control of BRR disease.

The TMO has also commissioned researchers and consultants from local universities to conduct a number of studies on topics that include the common biological tree decaying agents in Hong Kong, the wood strength of common tree species in Hong Kong, a Comprehensive Street Tree Management Plan for Hong Kong and a study on the Trichoderma species as a biological control agent against Phellinus noxius infected trees in Hong Kong. Their findings will be shared among the tree management departments and members of the industry, with a view to enhancing the standard of tree management in Hong Kong.

Q15: Will the TMO make reference to overseas experiences in the treatment of BRR disease?

The TMO has been meeting the Urban Forestry Advisory Panel, which is made up of local and overseas experts, on the control and treatment of the disease and to explore ways to tackle it. In 2011, we shared and exchanged views with Dr C.H. FU and Dr B.Y. HU, two visiting experts in phytopathology from Taiwan. Together we inspected the two trees (LCSD YTM/8 and LCSD YTM/11) on Nathan Road with the BRR disease. Since 2011, the TMO has been working closely with tree management departments once suspected cases of BRR infection were identified. An Introduction to Brown Root Rot Disease, which includes the diagnosis, treatment and proper handling of BRR infected trees was promulgated by the TMO in March 2011. To further enhance the management of BRR disease in Hong Kong, a precautionary and preventive approach for BRR management strategy has been promulgated in an expanded Guidelines on Brown Root Rot Disease in December 2012, incorporating the advice of the Expert Panel and taking into account their views and the topical literature from Europe, America and Taiwan (available here).

Moreover, staff from the TMO and relevant tree management departments attended the Seminar on Mature Tree Management held in Taipei in August 2012 to exchange experience with and learn about techniques from tree experts in Taiwan in the treatment of the disease.

Q16: How does the TMO detect BRR disease?

There is a three-step approach to determine the presence of BRR disease in trees, namely:

  1. Symptoms (such as a thinning and yellowish crown, with leaves reduced in size or even dropped);
  2. Field diagnosis of signs (such as the presence of adhesive soil particles, mycelial netting on the mycelia sheath and fruiting bodies of Phellinus noxius);
  3. DNA tests.

The TMO will carry out further studies on the various methods for the detection and inspection of the disease.

Q17: What are the methods available for diagnosis of BRR disease on trees?

There are currently two main levels of diagnostic methods available for determination of BRR disease in trees, namely field diagnosis through visual assessment and laboratory diagnosis through fungal isolation method and/or molecular diagnosis.

A short educational video on BRR disease entitled "Educational Video on Brown Root Rot Disease - Diagnosis, Control and Management Strategy" was produced in 2013 to further promote the knowledge on BRR disease to the general public and the industry, which is available here.

About Maintaining Trees for Private Properties

Q18: Is prior approval from the Government required for tree removal within private lots? What are the application procedures?

In granting a plot of land, the Lands Department ("Lands D") executes a lease with the grantee who is required to comply with the lease conditions after becoming the owner of the land. Leases executed at different times contain varying conditions. Private lot owners have to check and comply with the lease conditions. Where there is no tree preservation clause in the lease of a private lot, the lot owner can employ qualified professionals to attend to the trees within the lot. Regarding the employment of qualified professionals, private lot owners can refer to the tree website of the Development Bureau for the list of contractors or professional bodies providing tree management services. Generally speaking, where the lease of a private lot contains a tree preservation clause, the lot owner has to, except in an emergency situation, make a prior application to the District Lands Office (DLO) of Lands D and obtain a written consent before removing or pruning trees within the lot. To apply for tree removal or pruning, the private lot owner is required to submit a report prepared by a professional meeting the requirements specified in the Practice Note Issue No. 7/2007 available at Lands D's website, providing sufficient justifications and evidence for consideration. In granting a written consent, DLO may impose conditions on transplanting, compensatory landscaping or replanting as deemed appropriate. For application procedures for tree removal or pruning and guidelines on report preparation, please refer to the Practice Note Issue No. 7/2007 of Lands D. Further enquiries can be made to DLOs, the contact details of which can be found at the website of Lands D.

Q19: What action will the Government take if a private lot owner carries out tree removal or pruning within his/her property without approval?

Where the lease of a private lot contains a tree preservation clause, if the lot owner carries out tree removal or pruning within the lot without DLO's written consent, appropriate action will be taken by DLO upon detection. Such action includes issuing warning letters to the owner, requiring the owner to carry out compensatory planting or pay a premium if retrospective approval is given.

Q20: Can tree removal or pruning be carried out by private lot owners in emergency situations?

For the sake of public safety, tree pruning or removal can first be carried out by the owner of a private lot if the tree within the lot is considered to pose an immediate danger to the public after assessment by a professional employed by the lot owner meeting the requirements of the Practice Note Issue No. 7/2007 even though the lease of the lot contains a tree preservation clause (see Q.23). But the lot owner or his/her representative has to submit a detailed report prepared by the professional to Lands D within 21 days after the pruning or removal of the tree. The report should contain the justifications and evidence for tree pruning or removal, photos taken before and after the pruning or removal works, and the required compensatory planting proposal. For details, please refer to Appendix II of the Practice Note Issue No. 7/2007 of Lands D.

Q21: What action will the Government take if a private lot owner fails to properly maintain the trees within his/her property?

Regardless of whether the lease contains any clause requiring the owner of a private lot to properly maintain the trees within his/her lot, it is the responsibility of the owner to properly manage his/her property including the trees planted on the lot. Private lot owners may be held liable for any casualty or property loss arising from their failure to properly maintain the trees within their properties.

In addition, if the lease contains clauses requiring the owner to properly maintain the trees and the owner fails to comply with the lease conditions, Lands D will, upon detection, take lease enforcement action in the capacity of the grantor of a government lease. Such action includes issuing warning letters to the owner concerned.