Monday, December 3, 2007

ISA HK/China --- HK Tree News (Tree Grill removal by cutting roots)

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Dear Station Members,

Attached is a recent media report showing a tree grill removal operation with re-surfacing of the tree planter.

A reader wrote in to complain about the root cutting & coating on the cut roots, & queried whether it would damage the trees. The management replied since the tree roots were girdling around the tree grills, they had to be cut off so that the grills &/or the cement around it could be removed successfully. The management also emphasized that the operating method was provided by an 'approved landscape contractor' & the cut surface of the roots would be painted with protective sealant with soil cover afterwards. A curb & re-tiling would be carried out so that the trees would be given an even better growing environment.

As shown in the photo of the attachment, it can be seen that a gap has appeared at the root collar level upon the forceful removal of the tree grill attaching to it. Any qualified Tree Climber/Worker with chainsaw operating experience would recall such appearance similar to a Bypass Cut on any tree part to be removed & would hesitate to define the stability of the tree when something like this has happened in the wind. Wound painting is an obsolete practice belonging to the 1950's & research has shown that the protective cover produced by the sealant would encourage decay rather than stopping it due to the moisture contained.

It is noticed that no Arborist advice appeared to be sought & the service of Arborist might have been deemed unnecessary for tree work of this kind. The 'approved' contractor's advice was regarded as sufficient.

If an Arborist was employed to provide technical advice in this case, as very likely as in Western countries or even in Singapore, it is likely that the Arborist would first study the damage occurred to the root system & whether the buried tree grill parts can be left in place with the excessive part cut off only, so that the stability of the tree would not be compromised after the operation. The Arborist would also study whether the re-surfacing with alkaline concrete & cement would alter the pH of the surrounding soil, & whether the renewed surface would add more weight to the existing root system for further compaction. It would be irresponsible for any Arborist to contemplate only aesthetics, & sacrifice the health & structure of the trees in longer term with potential risk of failure in wind to be created to the pedestrians & traffic below.

By now, ISA HK/China has already 83 Certified Arborists working in our territory. Besides the Civil Servants, we wonder how many of them have been asked to provide frequent tree care for our society. Are Arborists some kind of unwanted excess in our landscape industry? Then who should take our place & can they do our job ?

Or, should we carry on the same way as before to face the world ?

best regards,

Sammy Au
Station Manager

The ISA Mission - Through research, technology, and education, promote the professional practice of arboriculture and foster a greater public awareness of the benefits of trees. (

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