LCQ15: Tree management

Following is a question by the Hon Chan Hak-kan and a written reply by the Secretary for Development, Mr Paul Chan, in the Legislative Council today (November 7):


Recently, a branch of a Chinese Banyan tree at Lam Tsuen San Tsuen in Tai Po snapped, fell and hit a passing lorry, killing one person and injuring another.  Earlier on, a hundred-year-old Chinese Banyan tree at Park Lane Shoppers' Boulevard in Tsim Sha Tsui collapsed, injuring five persons.  A tree nearby was subsequently found to have diseases and thus removed.  Moreover, during the time when Hong Kong was hit by Typhoon Vicente and the Hurricane Signal No. 10 issued by the Hong Kong Observatory was in force, a multitude of trees fell in various districts.  These incidents of tree collapse have once again aroused public concern about the health of trees and safety issues.  In this connection, will the Government inform this Council:

(a) as the Development Bureau had stated, in its Progress Report on the Work of the Tree Management Office submitted to this Council in July 2011, that "Focusing on areas with high pedestrian or vehicular flow, tree management departments first carry out a tree group inspection for locations under their purview", of the number of trees in such areas which had been inspected by the authorities to date since the inception of the Tree Management Office; among those inspected trees, of the number which were found to have problems and required detailed inspections, as well as the total number of trees in need of risk mitigation measures (such as pruning, removal of wilted branches, treatment of pest and disease, and cabling and propping to support the trees, etc.);

(b) of the number of staff members in each of the relevant government departments who are responsible for tree management work, as well as the frequency of tree inspections and the time taken for each inspection by each department; whether the authorities will require the departments to complete the inspections within a specified time limit; if they will, of the details; if not, the reasons for that;

(c) given that the public can now report problem trees by phone, through the Internet or using mobile phone applications, of the average time taken by departments to deploy their staff to inspect the trees concerned upon receipt of reports, and whether the authorities will draw up any performance pledge in this regard; and

(d) in addition to publishing the list of problem trees on the web sites of the government departments concerned, whether the authorities will consider making such information available to the public through other channels (such as putting up warning notices or signage next to the problem trees); if they will, of the details; if not, the reasons for that?



It is Government's tree management policy to promote a holistic greening approach, embracing adequate space allocation for new planting, proper selection of planting species, quality landscape design and planting practices as well as proper works implementation in the upstream and through regular monitoring of tree conditions and professional vegetation maintenance downstream.  The protection of public safety is a priority consideration.

My reply to Hon Chan's question is as follows:

(a) The Government adopts an "integrated approach" in tree management work.  In short, the department responsible for the maintenance of an area or a facility is also responsible for the maintenance of trees there.  We have also referred to the guidelines of the International Society of Arboriculture in formulating tree risk assessment methods.  Tree risk assessment is conducted in two stages.  In the first stage, which involves an "area basis" assessment, the departments will first identify those areas with high pedestrian or vehicular flow under their management.  In the second stage, which involves a "tree basis" assessment, the departments will conduct tree group inspections at locations with high pedestrian or vehicular flow and identify trees that are important or have problems for detailed inspection in order to reduce potential tree failure hazards that may endanger the general public.

In 2012, tree management departments inspected about 22,500 tree groups at locations with high pedestrian or vehicular flow and selected 5,011 trees among them for detailed inspection.  The departments undertook about 19,350 mitigation measures, including pruning, removing dead branches, controlling pests and diseases, and cabling and propping as support to trees.

We cannot provide comparable data for 2011 and 2010 as the data collection methods for these two years are different.  In 2011, the tree management departments inspected about 20,000 tree groups at locations with high pedestrian or vehicular flow and selected 7,400 trees amongst them for detailed inspection.  In 2010, the tree management departments conducted detailed inspections for about 1,500 trees.

(b) The Tree Management Office (TMO) of the Development Bureau has a staff of 16 people, comprising professional, frontline and clerical officers.  The TMO is responsible for formulating tree management policies, developing operational guidelines and co-ordinating the tree management work of various departments.  The number of staff responsible for tree management work in the tree management departments are as follows:

Name of Department                No. of Staff
------------------                            ------------

Agriculture, Fisheries and                    86
Conservation Department

Architectural Services Department       16

Civil Engineering and Development      14

Drainage Services Department           16

Highways Department                        23

Housing Department                          31

Leisure and Cultural Services             210

Water Supplies Department               27

Lands Department                             12

The above-mentioned staff totals about 450.  Other staff members in individual departments may also carry out tree management work in the course of performing other duties.  In addition, contractors are hired to carry out tree risk assessment, inspections, tree care and mitigation measures.

For trees at locations with high pedestrian or vehicular flow under their management, the tree management departments normally conduct tree risk assessment once a year before the rainy and typhoon season.  For trees listed in the Register of Old and Valuable Trees, detailed inspection is required at least twice a year.  Trees that are found to have problems are inspected in a timely manner as and when necessary.  The time required for inspection of tree groups and individual trees may vary in different cases.  At present, the Lands Department is planning an inspection exercise for trees in the rural areas, targeting at trees on unleased government land and village roads with relatively high pedestrian or traffic flow.  The Department is compiling information on the village roads concerned to facilitate allocation of resources (including hiring contractors) for the inspection exercise and follow-up actions for problem trees.

(c) The departments will take action according to the nature of the problem tree reports received, which are broadly divided into two categories: (1) emergency cases - cases that may pose a hazard to the life or property of the general public; and (ii) non-emergency cases.  

In a case involving a collapsed or problematic tree that has given rise to an emergency situation where life or property is endangered, regardless of whether the land on which the tree stands is owned and managed by the Government or a private party, the Fire Services Department and the Police will deal with it in the first instance.  

For non-emergency cases, that is, when no risk is posed to life or property, the tree management department responsible for overseeing the land where the problem tree is will inspect and follow up on the matter as soon as possible under the "integrated approach".  For trees on private land, the Lands Department will notify the land owner concerned to take follow up action.

(d) A Tree Register has been compiled and information on important trees (including Old and Valuable Trees and stonewall trees) and problematic trees that require close monitoring is published through the Internet.  The Register contains detailed information on the distribution and conditions of trees as well as the mitigation measures taken.  It is updated regularly.  Apart from disseminating such information through the Internet, the tree management departments display information in the Register, including tree registration numbers, species names, responsible departments and contact telephone numbers, on tree labels attached to tree trunks for public reference.

Ends/Wednesday, November 7, 2012
Issued at HKT 15:28