Monday, April 27, 2009

ISA HK/China --- Tree Assessment

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Dear xxx,

Thank you for your message.

What you have enquired may be of a nature of interest to a lot of our Station Members in our territory of HK, Macau, Taiwan & China, since the subject of Tree Assessment has become popular after the result of the Coroner's Inquiry of the fatal Stanley Tree Failure was announced. We therefore wish to reply with our best knowledge in an open Station Mail for public broadcast while protecting your identity. We hope we can have your understanding on this.

Before you would like to enter into the complicated subject of Tree Assessment, we would like to advise you to first study into the following literature for necessary knowledge:

1. Tree Biology (You first have to understand how a tree functions before anything else, & Tree Biology is NOT Plant Biology)

a. A New Tree Biology --- Alex Shigo
b. Modern Arboriculture --- Alex Shigo
c. Tree Anatomy --- Alex Shigo
d. A New Tree Biology Dictionary --- Alex Shigo

2. Tree Bio-Mechanics (The biggest enemy of a tree is wind. You must understand how a tree or its part may fail in wind)

a. The Face of Failure --- Claus Mattheck
b. Stupsi Explains The Tree --- Claus Mattheck
c. Updated Field Guide for Visual Tree Assessment --- Claus Mattheck
d. Tree Structure & Mechanics Conference Proceedings (How Trees Stand Up & Fall Down) --- Smiley & Coder
e. A Photographic Guide to the Evaluation of Hazard Trees in Urban Areas --- Matheny & Clark
f. Evaluating Tree Defects 2nd edition --- Ed Hayes

3. Roots & Soil (It is the roots & soil friction that keep a tree standing up. However, root invasion can damage infra-structure like sidewalk heaving, blocked pipes & cracked drains)

a. The Landscape Below Ground --- Watson & Neely
b. The Landscape Below Ground II --- Watson & Neely
c. Reducing Infrastructure Damage by Tree Roots --- Costello & Jones
d. Urban Soils (Applications & Practices) --- Phillip Craul

4. Diagnosis & Plant Health Care (If you do not understand whether a de-foliation situation is caused by pests, pollution or drainage, how can you write your report?)

a. Abiotic Disorders of Landscape Plants (A Diagnostic Guide) --- Costello, Perry, Matheny, Henry & Geisel
b. Plant Health Care for Woody Ornamentals --- John Lloyd
c. Arboriculture --- Harris, Clark & Matheny

5. Legal Consultation (What is the legal consequence of your Arborist Report? Are you inviting Law Suit?)

a. Tree Law Cases --- Lew Bloch
b. Arboriculture & The Law --- Merullo & Valentine
c. Arboriculture & The Law in Canada --- Dunster & Murray
d. Guide for Plant Appraisal --- Council of Tree & Landscape Appraisers of North America
e. Trees & Development --- Matheny & Clark

Since Tree Climbing is usually required for Canopy Inspection for tree architecture & defects, with pruning & removal as a recommendation frequently appearing in Tree Assessment in our territory, the following literature would become useful to you:

6. Tree Climbing

a. Tree Climbers' Guide 3rd Edition --- Sharon Lilly
b. The Tree Climber's Companion 2nd Edition --- Jeff Jepson
c. Arborist Equipment 2nd Edition --- Donald Blair

7. For Tree Work

a. Tree Pruning --- Alex Shigo
b. An Illustrated Guide to Pruning 2nd Edition --- Ed Gilman
c. The Art & Science of Practical Rigging --- Donzelli & Lilly of ArborMaster
d. ANSI A300 (Part 1)-2001 Pruning Standard Practices (Pruning) for Tree Care Operations --- American National Standards Institute
e. ANSI Z133.1 - 2006 Safety Requirements for Arboricultural Operations --- American National Standards Institute

The Arborist Profession is advancing daily with research & discovery from all around the world. It is much recommended for you to join ISA Membership to receive the following update for your continuous education:

8. Update & Education

a. Arborist News --- ISA
b. Arboriculture & Urban Forestry Scientific Journal --- ISA
c. Annual International ISA Conference --- held in a different place on earth every year with international Arborists gathering to share latest knowledge, research & equipment

All above information can be obtained at ISA online in It is our recommendation for you to study through them all before joining an apprenticeship under an experienced Tree Assessor like our Independent Practicing Arborist (IPA, or similar, to learn on how to assess trees on site. We shall be happy to give you a list of qualified personnel for your onward pursue.

Assessment for a tree is like medical examination for a human. No doctor would like to diagnose & operate incorrectly for a patient. At the same time, Tree Doctors should not remove the wrong tree by incompetence. As a Tree Assessor, you must remember that anything written down by you will be held to a higher degree of 'Duty of Care' in Common Laws, since your given details can be verified by another Arborist in a Court Room situation. Measurements, observations & recommendations can all be testified on site & this is the scientific side of our discipline. You therefore will be held responsible for any wrong-doing if Negligent.

We hope by now we have not frightened you to enter into the sensitive world of Tree Assessment. In reality, thousands of Arborists around the world are doing Tree Assessment everyday. The Station Manager himself has assessed hundreds of trees in the past 12 months already. A lot of Arborists sustain their income by Tree Assessment & Tree Assessment is the Crown Jewel in our Profession. It's just that you have to be careful & prudent all the way with adequate knowledge & experience on hand to do it. Never do it just for quick bucks if not sure, & you will get some good night sleep by remembering that.

Thank you for your enquiry again & please do not hesitate to call anytime if you have further questions.

best regards,

Sammy Au
Station Manager

"If a tree is not designed, installed, maintained & inspected properly, it is likely to become a liability rather than an asset."

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

----- Original Message -----
From: xxx
Sent: Monday, April 27, 2009 11:39 PM
Subject: How to do Tree assessment

Dear Station Manager,

I am your CA no. HK-xxxxA. I want to learn Tree Assessment because my boss demands it now. But I did not know where to start. Please explain with my thanks.

Always support you. You are doing good job.




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