Wednesday, October 29, 2008

ISA HK/China --- Tree Felling by a 'Specialist Contractor'

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Dear Station Members,

The Station Manager was called out by a housing estate to supervise Tree Pruning for their Mature Trees this week. While he was there, he saw a spectacular Tree Felling exercise by a local 'Specialist Contractor' who performed their work completely different from our usual international practices which is worth sharing with our Station Members.

In order to protect privacy of the parties involved, no details with regard to location, individuals or even tree species are given here. ISA HK/China has only academic interest in the event & would provide facts on the technical side only.

The tree to be felled was about 25m tall & it appeared either dead or dying. The 'Specialist Contractor' has hired a RB crane to do the cutting & lifting without Tree Climbing. The ' Tree Worker' doing it was said to be felling tree nearly every week & was notified to be well versed for the job. He began by putting himself inside a steel cage which was then hoisted up to 2/3 the tree length where he would begin the cutting. The only PPE he was wearing was the safety helmet, & he was without Fall Arrest Hardness of any kind. He brought in a nylon sling with him & tied that at the point of cutting which was also about 2/3 of the height of the tree. After securing the sling to the tree, he began cutting the trunk with a Hack Saw, not Chainsaw, from both directions.

After some heavy duty of removing trapped saw & strenuous severing in by hand, the tree suddenly snapped clean without any warning. As the trunk broke away from the tree, being tied together with the steel cage on the same anchor point above on the crane, the removed stem naturally swung & hit the cage with a bang, causing shock & swing to the cage. The worker inside could not stand still & slipped, but luckily he was not thrown out of the cage. After some commotion & settlement of the cage & removed trunk, the crane lowered the tree part & the steel cage together to the ground. The removed trunk was then cut into sections by ground staff for storage.

The same action repeated 3 times for the 25m tree to be cut to the ground. It must have been a thrill of a lifetime for the worker inside the cage & the audience were watching it with equal excitement. When the management staff asked the Station Manger for comments on safety of the work, the Station Manger just smiled & said they have employed a 'Specialist Contractor' who should know what they were doing.

HK relies on 'Specialist Contractor' to do our Tree Work & the 'Specialist Contractor' may nowadays require a Certified Arborist (CA) to sign for tendering, but not sure how often on site for actual supervision. Yet again by passing just 200 multiple choice questions to become a CA in our territory without actually demonstrating climbing & rigging, can this CA really supervise actual Tree Work? If anyone has any objection to the installation of the Independent Practicing Arborist (IPA) status in our territory, they should come with the Station Manager on site some time to find out how Tree Work is done locally. The Arborist Profession all around the world is known to be a Practitioner Trade with hands on skills & knowledge. Credential collection alone may not shine the actual value of this unique profession.

TCHK ( has been kindly invited to perform a Tree Rigging & Felling exercise by Fung Kai School from 9am to Noon on Saturday Nov 1, 2008 for one of their hazardous trees. The photo of the 13m tall Alstonia to be felled is given in the attachment. Proper equipment & procedures in accordance with international practice will be demonstrated by TCHK Chiefs who will carry out the work. Fung Kai School has very kindly given us the permission to invite our Station Members to attend the event as an educational session for proper Tree Work. Anyone who is interested to attend may come by foot only, not by car, since all parking spaces will be used up for Work Zone & debris storage.

Let's hope who do not believe in proper Tree Work should be carried out by trained personnel only can come & see it with their own eyes for comparison on Nov 1. If not, ISA HK/China will be giving the same education to our brothers & sister up north very soon in China. We certainly do not wish to see if they can do it under ISA practice in future, whereas we here can not.

best regards,

Sammy Au
Station Manager

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