Monday, July 9, 2007

ISA HK/China --- Review of ETWB Tech. Circular no. 3/2006 on Tree Preservation

Dear All,

This Station has received a copy of the Environment, Transport & Works Bureau (ETWB) Technical Circular (Works) No. 3/2006 on Tree Preservation recently & has carried out a general review on the subject. This Circular may affect local developers, consultants, contractors & certainly arborists. As this is an important document listing out the guidelines & principles on Tree Preservation work on Govt site as well as any private development on leased Govt land with tree protection clauses stated in, all those who are affected are encouraged to study the contents of this Circular which can be downloaded from:

The following points about this Circular are attempted by this Station for the interesting reading of our Members:

1. This is the most up-to-date guideline on Tree Preservation by ETWB with the agreement of a string of various Govt Depts including Housing Dept, AFCD, Buildings Dept, & LCSD. It is therefore broadly represented & will be referred by various Depts in future for tree practices.

2. This Circular should be used in conjunction with the Register of Old & Valuable Trees (OVT) in ETWB TCW No. 29/2004.

3. Lands Dept (LandsD) is responsible for coordinating Tree Preservation on leased land.

4. Definition of a Tree is if its trunk diameter measures 95 mm or more at a height of 1.3 m above ground level (DBH height). Some mature shrubs, palms, succulents & bamboos may also meet this category.

5. This is a Technical Circular & not an Ordinance. It has not been presented to the Legislative Council for the law making process. It also did not state whether this Circular had been consulted with academics, professional bodies, conservation groups or the general public. In the unlikely scenario of a Court challenge, the Court judgement can override this Circular if the other side can prove negligence or unreasonableness for certain practices within this Circular. Expert Witness will be required for such challenges.

6. Clauses 15 - 17 of this Circular put emphasis on the 'conservation & amenity value' of a tree, & encouraged tree transplant without making reference to tree size & age. There is no mention on the structure, hazard potential, safe & useful life expectancy of a tree. Aslo, no clear definition is given on how to determine on the 'conservation & amenity values'. This may become a point of dispute if such terms are only viewed upon as a subjective opinion without scientific guidelines backed up by valid research.

7. Clause 27 on Compensatory Planting is still taking the approach of 'balance sheet accountancy'. Compensatory Planting is required to be of ratio of not less than 1 : 1 in terms of quality & quantity. In short, it is 'an eye for an eye' approach disregarding whether the future site can really accommodate all the Compensatory Planting. We all have seen sites in HK squashed with 'compensated trees' without consideration for the future crown & root development. Such trees may not live long. This could be an arguing point in Court if so raised by the Defendant.

The other side of the argument is that in a lot of local sites, if sufficient space has to be provided for the healthy & long term survival of the 'compensated trees', there may be no room left for the structures to be installed. This is the agony in deciding upon the quantity of the 'compensated trees'. Just imagine how much room would the Tai Po Wishing Tree take for the crown & root healthy growth! Thereafter, the 'quality' of the compensatory trees was desired to be no less than 'heavy standard' (usually above 95mm DBH). This again seemed to be taking the China approach of 'the bigger is the better' & without the consideration of research finding that younger trees are more resilient & faster growing after installation.

8. Clause 28 stated that a clear height of 4.5 m or more is required for tree planting under elevated/overhead structures. Therefore, tree planting under canopies are allowed. This is a unique feature in HK whereas most parts of Western countries would not adopt such a practice for arboricultural reasons.

9. Clause 34 stated that the Senior Landscape Architect (SLA) or the Project Director of the landscape consultancy would be responsible for tree surgery work. Responsibility will bring liability. Poor pruning can bring about tree failure in future & has led to many court cases in the West over the years.

It is unfortunate that our society has not yet recognized Arborist as a profession, although this Station is trying hard to train up the first batch of Certified Arborists (CA) in our Govt Depts. Certified Arborist will receive training in pruning & will be tested in their credential for pruning knowledge, although not for the practical part up a tree with cutting tools. It may take some time before our currently trained CA's to become experienced enough to handle proper pruning in design & supervision. Pruning takes time & practice to master. Nursery experience is much prefered in line with literature research. Good nurserymen have to practice proper pruning in their production. CA's must touch trees. To be able to climb is even better.

10. Clause 35 specified the pruning method is to follow that of BS 3998:1989. There are only two pages (p.4 & p.5) giving information on pruning in this BS. Also, it was written in 1989, some 17 years ago whereas arboriculture has made tremendous advancement including the proclamation of Compartmentalization of Decay in Trees (CODIT) in the 1990's. In a Court action, tree failure following Clause 35 could be challenged by Arborists for effectiveness & the Judges will study all details given in order to achieve the final decisions.

11. Clause 35 has also made a positive move in requiring tree works to be carried out by contractors with a 'competent person with arboricultural knowledge' to supervise the work. Whereas such requirement is not required at the Project office or consultancy level as per stated anywhere in the Circular, it is now required at the contractor level. Clause 38 has defined such 'assigned person' to have training from institutes such as CITA (not that this Staiton is aware of for any arboricultural courses so offered so far) or similar courses as considered appropriate by the Architect/Engineer/Supervising Officer. This is a flexible definition as this gives the authorities the power to decide who will be acceptable to be the 'assigned person'. As more arborists are trained up in future including those so trained up by this Station, the career prospect for our CA & CTW (Certified Tree Worker --- Tree Climbing Specialist) may be promising.

12. Clause 39 went as far as requiring the Particular Specification to incorporate in the tender document that 'to require the contractor to assign a competent member of the site supervisory staff to oversee & supervise the tree works under the Contract'. This Station interprets such requirement as our CA/CTW are likely to be the acceptable personnels, with the CA overlooking the administrative & design matter, & CTW carrying out the actual tree work under the supervision of the CA. This Clause is very positive indeed.

13. Clause 40 spelled sout the punishment of tree damage or unauthorized removal of trees on site by the Contractor but it also mentioned the exemption condition of 'unless the Architect/Engineer/Supervising Officer is convinced that the incident is justifiable due to exceptional circumstances'. If such an event should happen for the contractor, a CA is best employed to honestly produce an explanation & defense. ISA CA's in HK so far have a reputation as being honest & possess good integrity, values that this Station wishes to maintain at least in our CA Family Channel. This Station hopes to turn over a new leaf for arboriculture in HK as different form general landscaping which has burnt itself into chaos due to intense competition in the past.

14. Clause 42 listed out clearly that trees on private land without a tree protection clause as a constraint will not be affected by this Circular. In short, land owner there can cut down any of their trees, with the exception of OVT, at will. This may be the area that our environmentalists & media wish to supervise in their activities, as these unprotected trees will be out of our Govt control.

15. Claus 43 gave criteria on cases of 'Serious Incidents of Unauthorized Tree Felling or Damage of Trees' to be those attracting 'media attention'. Therefore, our media will play an important part in reporting such malpractice.

16. Appendix B in this Circular gives definition on the responsibilities of various Govt Depts on their tree domain.

The above Circular has been a concerted effort by our Govt to protect our trees. As no regulation can be perfect, nor can it please everybody, at least we can see the intention & good conscience of our Govt to do her best within the resources available to protect the trees of HK for public interest. Tree preservaton in HK may be regarded to be lacking behind Western Nations by some, but it is now moving ahead with this Circular. Our Govt has done a good job in producing this Circular & deserve our respect indeed.

The above comments are meant to be constructive by this Station & can not be treated as legal advice. All above are meant to be merely intellectural discussion within our Station Members. Each individual reading it should carry out his/her own detailed analysis & feel the good intention behind it before making final decisions. As likely that this message will be pirated over the internet, any reader of this e-mail should study the above Circular with care & respect before entering into any hasty decisions.

best regards,

Sammy Au
ISA HK/China Correspondence Station Manager
ISA Certified Arborist no. ML-0174A
ISA Certified Tree Worker (Climbing Specialist) no. CTW-1645C
Member of International Plam Society
Member of Royal Horticultural Society, UK
Life Member of Intitue of Horticulture, HK
Co-owner of Huadu Eurasian Tree Farm (currently the only nursery in China trying to grow trees to ISA requirements, from seeds)


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