Explanatory Notes for Form 2

1. General Information

 The Inspection Officer shall make reference to the previous tree inspection records, if available, to help to identify changes in the site conditions and tree conditions.

1.1 Inspection Officer and Endorsement Officer

 For outsourced tree inspection works, the consultant / contractor staff can serve as the ‘Inspection Officer’ to conduct the inspection.

 The ‘Endorsement Officer’ is the supervisory / managerial staff at a rank higher than that of the Inspection Officer who oversees the Tree Risk Assessment process. For outsourced tree inspection works, the supervisory / managerial staff of the consultant/contractor firm can serve as ‘Endorsement Officer’.

 ‘Inspection Officer’ and ‘Endorsement Officer’ for Form 2 need to meet the requirements on academic / professional qualification and / or training, and work experience as listed in Appendix 7.

2. Location Information

 Please refer to the Explanatory Notes for Form 1 in Appendix 5.

3. No. and DBH of Trunk

 The tree with multiple trunks should have each trunk numbered in sequence (i.e. #1, #2…etc.) and the photographic records should include such numbers. The DBH should be measured at 1.3 m above the ground. For measurement of trees with multiple trunks, please refer to AFCD’s Nature Conservation Practice Note No. 02 (Rev. Jun 2006) ‘Measurement of Diameter at Breast Height (DBH)’(http://www.afcd.gov.hk/english/conservation/con_tech/con_tech.html).

4. Tree height

 The estimated height of the tree above ground to the top of the tree crown. For accurate measurement, making use of a clinometer / range pole is recommended.

6. Age class

 A broad indication of the tree age class would suffice.

7. General condition, Crown condition, Branch condition, Trunk condition and Root condition

 Refer to ‘Pictorial Guide for Tree Maintenance to Reduce Tree Risks’

(http://www.trees.gov.hk/filemanager/content/attachments/PictorialGuideForTree

MaintenanceToReduceTreeRisk(eng).pdf

)

 Thorough inspection on the root collar condition is important to ensure that structural defects adversely affecting anchorage of the trees can be identified as early as possible for adoption of proper mitigation measures.

 Root collar inspection should include sounding test and examination of the soil and root conditions using proper hand tools.

 The findings, analysis and recommendations should be elaborated in the comments with adequate photos to illustrate the condition of root collar.

 Pests and diseases which can lead to severe health and structural problems, such as BRR Disease and decay caused by Ganoderma spp. and termites, should be identified with adequate photos, if any.

 Further detailed examination and analysis by advanced equipment, such as tomography or resistography, should be conducted as appropriate to ascertain the condition of the trees, particularly for OVTs and large mature trees in which particular concern is required for their preservation.

8. Site condition

 Restricted root growth area inside dripline – The Inspection Officer should tick the most appropriate box to reflect the site condition.

9. Target

 Please refer to the Explanatory Notes for Form 1 in Appendix 5.

 ‘Use under tree’ – The Inspection Officer should tick the relevant use of areas under the tree. Please specify in the ‘Others’ column as appropriate.

10. Hazard rating

 In tree risk assessment, a potential hazard exists if tree part(s) is / are identified as a likely source of harm. The hazard rating helps to conclude the overall risk level and decide on the appropriate follow-up action so as to reduce the risk posed to public safety. The focus is on identifying and prioritising appropriate hazard abatement measures for high-scoring trees. The hazard rating consists of three components:-

Failure Potential

This relates to the likelihood of failure of a defective tree or branch.

Size of Part

This relates to the diameter of a defective part which would affect the consequence of failure.

Target Rating

This relates to use of the target area which would affect the likelihood of impacting a target by the concerned defective tree part.

 Generally speaking, trees with a total score of 9 to 12 in the hazard rating as evaluated using TRA Form 2 warrant special attention.

11. Remedial / Risk Mitigation Measures

 To recommend remedial / risk mitigation measures to reduce the potential tree risk.

 To provide a record of continuous tree monitoring / management efforts.

 The removal of defective parts of the tree, installation of support system, pest and disease control should be undertaken in a timely manner. It is necessary to mitigate the tree risk promptly to protect public safety.

 Records and photos on mitigation measures should be provided.

 The date of completion of the risk mitigation measures should be recorded as appropriate.

12. Comments

 Categorisation of the TRIAGE system (if any) and additional information on trees which require further attention should be recorded to facilitate identification of appropriate follow-up action and future monitoring.

 Provide a critical review and analysis of the collected information

 Provide comparison with previous records and a comprehensive recommendation, if required, based on the systematic observation as detailed in the Form 2.

 Confirm the major structural defects or health problems have been mitigated after the completion of mitigation measures in the Form 2 for downgrading a TRIAGE tree from ‘Red’ category to ‘Yellow’ category.

 Record the recommendation for downgrading a TRIAGE tree to ‘Yellow’ category.

13. Attached Information

13.1 Site Plan and Tree Photo

 Tree location and photo(s) should be attached to Form 2 in every case. For photographic record, please refer to ‘Photo-taking Guidelines for Tree Risk Assessment’ in Appendix 6 for the detailed requirements.

13.2 Resistograph Chart and Tomograph

 If a tree inspection by resistography or sonic tomography is conducted, attach the inspection record as supplementary information.

13.3 Others

 Other observations requiring follow up actions such as overgrown ground vegetation near root flare / trunk base requiring clearance by the management department or agent to facilitate root collar inspection have to be explicitly recorded.