Friday, September 19, 2008

ISA HK/China --- HK Tree News (Contracting out Tree Inspection and Public Commnet on Tree Work)


*** Our weekly Station Mail is for the information of Station Members only, but Station Mail has given up copyright & can be freely circulated. For administrative reasons, comments from outsiders are usually not entertained & may be circulated within our system locally & overseas. Please note Station Mail is sometimes given in Blog at http://isahkchina.blogspot.com/ , although images are usually not attached due to size. ***

Dear Station Members,

Below & attached are two sets of recent news concerning our local trees in the media:

(A) Contracting out Tree Inspection Work

The media has been asking for opinions among landscape professionals on contracting out Tree Inspection & Risk Assessment in HK. Some are in favour & some have reservation which is all natural in a free speech society.

The essence of the discussion really rests with the reliability & sustainability of contracting out the work, & how the work is going to be carried out & by whom. The HK Govt has by tradition employed many consultants in the engineering & planning field, & ISA HK/China has every confidence that our Govt has the ability to issue the right direction & requirement for contracting out Tree Work, if it ever becomes necessary.

There should also be a grading system as to which level of Tree Inspection is to be carried out by what level of expertise. For example, if the public untrained in arboriculture is to be invited to carry out elementary Tree Inspection work, then what should the see & report? The next level may be the Certified Arborist (CA) who are tested by 200 multiple choice questions only to become Certified. Then should they be asked to inspect trees which would require Tree Climbing for canopy defects? Should we decide on a size of a tree to be inspected for CA & beyond for a higher level like the Independent Practicing Arborist (IPA) who has a better experience & reliability?

For a detailed Risk Assessment on a mature tree, the Tree Assessor would need to be familiar with subjects like Tree Biology, Tree Biomechanics, & Tree Work like Structural Pruning, Cabling & Bracing, Decay Detection Methods, etc. Tree Climbing is frequently necessary to inspect structural faults in canopy & the Tree Assessor must have keen observation & experience in the body language of a mature tree. ISA HK/China would recommend training in advanced Tree Biology of Dr. Alex Shigo & Biomechanics by Prof Mattheck as a basic start in carrying out this kind of work, & it appears that all these are way beyond the testing requirement in the current CA exam.

It is therefore apparent that different level of expertise would be necessary to do different level of work, & every level should really take part to form a complete service to help our trees. Trees nowadays are public properties & they are regarded as permanent structures in our city, like lamp posts & traffic lights. Public participation would also encourage our public to protect trees & public resentment would be quelled once they have learned that trees are living creatures just like human beings. Trees do need care. ISA HK/China encourages public involvement in Tree Care & sees this is a way to better protect & preserve our valuable trees.

(B) Public Comment on Tree Work

This message is given in the attachment in Chinese from a local newspaper. ISA HK/China is only interested in the technical part for the discussion & not anything else.

ISA HK/China agrees with the Expert's opinion which is underlined in the message that to understand tree health, the inspector has to touch trees rather than photos alone. Tree Climbing may be necessary at times if canopy problem is suspected, e.g. decay & cracks. Tree Pruning has always been a complicated subject under intensive study at ISA all around the world. Pruning to a tree is like surgery to a human. Once any tree part is removed, it can not be nailed or glued back, & the tree will develop responsive growth to try to recover the lost part.

Another important consideration in proper pruning is the Wind Loading on a tree after pruning & in future growth. It appeared in our territory that a lot of trees failed its parts after pruning, not after installation. If the pruning creates large wound which can not be successfully compartmentalized by a tree lacking vigour, the decay would develop inside to spread to the root crown & topple the tree in wind. In the opinion of ISA HK/China, what trees have suffered most in our territory is from bad pruning, yet proper pruning would require the knowledge of Tree Biology & Wind Mechanics which are beyond the knowledge of common landscape workers. Pruning is much more than cutting at the right angle from Brach Bark Ridge to Branch Collar, but on why, where & how much to remove with what.

Tree Work is specialist skills known around the western world. Even in Britain among the many British Tree Experts discussed with the Station Manager in ISA meetings & communication, Tree Work over there is usually handled by their Arboricultural Officers who are trained & experienced Arborists. If HK is to carry proper tree care, this may be the general direction we suppose. We respect that our LCSD has the most number & experienced Arborists & best equipment in our Govt to carry out Tree Care. It would be good if LCSD may wish to help out on that.

best regards,

Sammy Au
Station Manager

"Trees are good for the community. Trees need care like human beings. Arborists are the Tree Care Professionals."



市場足承接外判樹木管理


9月10日 星期三 05:10

【明報專訊】康文署正研究是否需要把樹木護理工作外判,有園境師和樹藝師皆表示,本港有足夠承建商和樹藝師接收約72萬棵樹木,包括逾500棵古樹的檢查和護理工作;但有樹木專家表示,全面外判可能導致質素參差,建議康文署保留護理古樹的權力。


港有逾10間綠化承建商


園境師學會前會長、香港顧問園境師協會主席劉興達表示,本港有10多間綠化承建商從事綠化工作,包括園景設計及規劃、樹木檢查及護理等,部分一直為康文署工作,若政府開放保育樹木工作,相信有足夠能力承接。他又指出,政府可透過制訂保育樹木政策,監管園境師和承建商分區管理約72萬棵樹木,「當局可按區招標,聘請顧問公司評估區內所有樹木的重要性、存在風險及護理方法等,撰寫報告和落實護理計劃」。


國際樹木學會中國地區分會會長歐永森指出,本港約有110名註冊樹藝師,「樹藝師只通過筆試,與具實戰經驗、攀樹師牌照等的獨立執業樹藝師(IPA)不同,IPA 能為檢查報告負上法律責任,亦不偏幫政府或保育組織,能獨立工作」。本港現有5至6個執業樹藝師,有能力檢查全港樹木。


環團憂外判商參差


身兼樹藝師的長春社保育經理蘇國賢指出,他認為外判商的質素參差,而且會隨重新招標而不斷更替,不宜負責保育古樹工作。「始終古樹一死就沒有,康文署不能只看外判商的報告就當完成管理工作。」他認為古樹的管理應由康文署負責,至於其他樹木,則可透過加強監管外判。


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