Background

The Task Force on Tree Management led by the Chief Secretary for Administration published a report entitled "People, Trees, Harmony" in June 2009. Pursuant to the recommendations of the report, the Tree Management Office (TMO) introduced a new tree risk assessment and management arrangement with the promulgation of "Guidelines for Tree Risk Assessment and Management Arrangement" for compliance by tree management departments to better protect public safety.

• Guidelines for Tree Risk Assessment and Management Arrangement (10th Edition)
• Form 1 (TRAM 10th version)
• Form 2 (TRAM 10th version)
• Form 1 Explanatory Notes
• Form 2 Explanatory Notes
• Guidelines on Audit of Tree Risk Assessment (Appendix A)
• TRAM World Diagram

Tree Risk Assessment

In essence, the objective of tree risk assessment is to reduce the risk posed to personal safety and property by trees that may have problems at locations with high pedestrian and vehicular flow by taking timely action through a systematic methodology and procedures. Tree risk assessment is conducted step-by-step in two stages:

• Area Basis Assessment
  Departments first identify those areas with high pedestrian or vehicular flow under their management.
• Tree Basis Assessment
  Departments carry out tree group inspections in a systematic manner at locations with high pedestrian or vehicular flow to identify trees which may need particular care (such as Old and Valuable Trees and stonewall trees) as well as dead trees and trees with major health or structural problems which may pose hazards to the public.

Mitigation Measures

Depending on the tree conditions, appropriate risk mitigation measures (such as pruning, removal of wilted branch, treatment of pest and disease, and cabling and propping to support trees) are prescribed. If there are no other feasible remedial measures, departments will remove hazardous trees as a last resort so as to eliminate the threat to public safety.

Monitoring

To ensure that the tree risk assessment is properly carried out, tree management departments are required to adopt quality assurance measures such as close supervision of frontline duties and conducting internal audit. In addition, the TMO carries out desk-top checking of the tree inspection forms completed by departments on a selective basis and random inspection on site of the condition of trees on Government land to ensure that the tree risk assessments are conducted in a professional manner.