IS AHK/China --- Review of selected literature published by AA of UK

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Dear Station Members,

The Arboriculural Association (AA) of the UK, another well known arbor group to a lot of our Civil Servants, was set up in 1964, 40 years after ISA which was established in 1924. AA currently has around 2,000 members mostly of UK origin, as compared to the over 20,000 members of ISA from all around the world. AA mainly focuses on trees in the British Isles since it is a national body.

Traditionally for our Civil Servants when it comes to arbor training, a lot of them would be sent to the UK to learn the standards & practices laid down by the AA & relevant institutes. Therefore, this Station has taken some time to study the AA particularly in their training & literature, to see whether there is anything that our Station can learn from them.

At present, the AA credentials are not interchangeable with those of ISA. AA members would have to pass the ISA exams to get ISA credentials. It is an interesting fact that in our Station's history of several CA exams so held for the HK people, those who have AA background have not passed the CA exam in one go so far. The highest passing mark for CA exam for the HK candidates is currently held by a National Parks Board of Singapore (Nparks) trainee at 93% in Dec 2006.

For anyone who wants to understand more about AA, their website is www.trees.org.uk .

Please be reminded that Britain is situated in a temperate region & London is more northern in latitude than Beijing. British trees would be rather different from our tropical & subtropical trees of HK/China in both growth rate & perhaps even wood properties.

This Station has tried to carefully comb through the structure & literature of AA in the past few months already. Please kindly note that it is not the intention of this Station to compete AA with ISA, because it would be wrong to do so & we are in no position to do so. On the other hand, this Station has heard that negotiation has been going on for AA to merge with ISA for some years. ISA would sincerely like to see AA joining ISA in future.

AA does not publish as many books & videos as ISA does. In the assortment of AA publications available online, this Station has found the following literature of particular interest for the development of our Station Members:

1. European Tree Pruning Guide --- This is a small handbook for reminding tree practitioners on how to properly prune European trees. This book has incorporated a lot of ISA principles in tree pruning as any CA would learn & can be useful as a pocket guide for pruning work on site.

2. A Guide To Good Climbing Practice --- This is the British answer to ISA Certified Tree Worker (CTW) training & in effect, the description is very similar to any CTW would learn. This little book has also fantastic pictures contained & the Station Manager has met some of the demonstrators in the book during their visit to HK at the HK Flower Show 2007. One thing a lot of CTW may not agree with the book in saying that tree climbing on rope is an option after access with mechanical means such as a platform track has exhausted. CTW are proud to climb & would regard mechanical means as an aid. The Station Manager reckoned the poor side of British weather may have some bearing on this decision, & he was living in the UK from 1973 to 1984 for study & work to find out. Also, Eye Protection such as goggles against insect attack or branches poking eyes, was not shown to be worn by the tree climbers in this book at times. There was also no description explicitly requiring this safety practice in any part of the book as aware of, whereas Eye Protection is mandatory for ISA Certified Tree Climbers.

3. Guidance Notes no. 4 Visual Amenity Valuation of Trees & Woodlands (The Helliwell System) --- This is the British method of tree appraisal for urban & woodland trees. The procedures set out are rather different from the ISA method of the Council of Tree & Landscape Appraisers (CTLA) used in North America. This Station would not compare to say which one is better since there is hardly any ground of comparison with our local system. This Station is not aware of any published appraisal method so provided by our Govt Depts on unapproved tree felling, topping or interference for public reference.

4. Guidance Notes no. 6 Preparing for Prosecution --- This is a relevant guide for arborists to learn on how to prosecute or defend for clients in Courts. This book does not go into the complexity of arbor knowledge or legal procedures, but rather provide the framework on how an arborist could do when it comes to carry out tree dispute for litigation. This book is recommended to be read by CA to enhance their legal knowledge, although it fell short of providing exemplified case studies.

5. Guidance Notes no. 7 Tree Surveys --- This books gives guidance to good practice in preparing proper tree survey for arborists. The contents are varying from some of our Govt departmental guidelines & have incorporated advanced technology such as GIS &GPS. Tree life expectancy is also mentioned as an important point in the consideration. This may be a good book for our tree surveyors to enhance their knowledge in their day to day work on site.


Our Station has always been a keen learner for anything good in the arbor world. It does not matter where it comes from as long as the knowledge can advance our development. ISA policies allow us to learn from the good & to bring them back to ISA for sharing. Therefore, we always look everywhere for good information.

May we strengthen ourselves in HK in knowledge for the eventual march on to China later to convert the 1.3 billion there.

best regards,

Sammy Au
Station Manger