Thursday, July 31, 2008

ISA HK/China --- 2008 Research on Tree Stabilization Systems



*** 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,

Attached is the latest research of ISA on the Tree Stabilization Systems for information to our local practices.

Tree Staking is a common practice in our landscape contracts due to the disability of landscaping trees to stand up in wind after installation. One major probable reason of this happening may be because the rootballs that come along with the nursery trees from China do not meet the international requirement of 10 x Trunk Diameter to have less weight below to stabilize the tree in wind. Another probable reason may be due to the low Live Crown Ration (LCR) which would raise the Turning Moment of a tree in wind since the majority of wind-catching area would be on top. Then if anyone would look carefully at most China nursery trees, they usually do not have good Taper to bend in wind as well.

The reduced rootball coupling with low LCR & poor Taper are again due to the common nursery production method in China. In most China nurseries, trees are planted densely like paddy or vegetables to maximize profit. Trees there have to fight for sunlight by developing a long slender stem which would lead to low LCR without Taper. Then when the tree is harvested, in order not to cut off the roots of the neighbouring trees as well as for manual carrying convenience while dragging it out of the densely man-made forest, the rootball has to be reduced & sometimes tree parts Topped. Occasionally there are trees planted in containers for hoping to minimize transplant shock, but either the containers would not meet the 10 x Trunk Diameter requirement or Girdling Roots would develop to make these trees a potential hazard in future planting.

Yet HK has to rely on China to supply nearly all our nursery trees today.

With trees of above qualities, we are not sure whether even the best Tree Stabilization Systems would help in protecting our landscaping trees in wind. Those with Girdling Roots would eventually become Time Bombs to hit somebody or something as well. The solution may really rest upon the use of quality trees that very few China nurseries can nowadays supply.

ETF has been promoting international nursery production methods to China growers but again has been ignored or even laughed at. Maybe if ISA Arboriculture would not develop among our brothers & sisters up north, HK will have to put up with using China quality trees, & then hope for the best ...

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. (http://www.isa-arbor.com/)

Monday, July 28, 2008

ISA HK/China --- The Singapore Experience (Episode 4, SGF Expo 2008)



*** 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,

It was a huge success for ISA HK/China to participate in the Singapore Garden Festival 2008 Expo (SGF). Over 50 candidates from our territory of HK, Macau, Taiwan & China have attended this SGF whether directly or indirectly informed by our Station. ISA HK/China has also learned that there were over 320 participants from many countries joining the conference & another 200 no. just for the Flower Show. This has marked the SGF an important event with international participation in the Asia Pacific Region.

Objectives of ISA HK/China to attend the SGF included:

1. To better network with regional counterparts around our territory & to promote ISA to anyone not yet learning its presence in Asia.

2. To promote quality trees of ETF & tried to use that to encourage arboriculture & ISA in the buyer's domain.

3. To promote proper arboriculture & tree climbing to any attendees from Macau, Taiwan & China.

4. To bring back knowledge of the latest arboricultural practices of Nparks during the Seminar & Day Tour of July 26.

We generally felt that all objectives have been successfully met during this visit. The Station Manager was also astonished to learn of the lack of acknowledgement of ISA arboriculture in certain Asian countries which are English speaking including India, Philippines & Brunei. Maybe these countries would have potential to develop ISA arboriculture as from their traditional practice.

There were several groups of visitors from China coming to the exhibition stand of ISA HK/China & they were amazed to learn of modern arboricultural practices & tree climbing from us. Nearly all of them used to believe topping was the only way to transplant a tree & they used to view tree climbing belonging only to the young & daring. Their concept of planting trees for only ' flowers & scent ' was deeply rooted. Tree structure & health for proper tree selection did not mean much for them. Tree Failures were regarded as only Acts of God & they have never heard of the term Tree Detective played by Arborists for legal disputes. All of them listened carefully to the introduction of the Station Manager on ISA & grabbed any Chinese notes that were available for the exhibition. If all of China would show interest like these candidates, ISA HK/China may be knocking on the door sooner than we have planned. This is yet to be seen.

Seminar & Day Tour of July 26 organized kindly by Nparks was the most educational of all. Several prominent designers & Arborists from Nparks delivered excellent talk on the current practices & concepts of tree planting & landscaping. ISA HK/China focused on the tree planting part of the discussion only & has brought back highlights as follows:

a. Tree planting in Singapore is regulated by the Park & Tree Act & Planning Act.

b. Trees are conserved in 4 major areas --- Tree conservation Area, Heritage Road Scheme, Heritage Tree Scheme & Nature Conservation.

c. Park Masterplan aims for 0.8 ha/1000 population for greenery purpose, & parks are to be linked together for convenience of visit.

d. Streetscape GMP includes parkway Treatment, Coastal Treatment, Forest Treatment, Rural Treatment & Gateway Treatment.

e. Greenery coverage of Singapore has improved from 35.66% of land coverage in 1986 to 46.59% in 2007. Nearly half of Singapore now is green when viewed from an airplane today.

f. Tree Failure Rate is quoted to be low, with thanks to regular Tree Inspection & Risk Assessment.

g. There are 204 Certified Arborists now working in Singapore, with about half working in Nparks carrying out various arboricultural duties from design, nursery stocks selection, transplanting, maintenance, inspection, risk assessment, conservation & construction protection.

h. Trees are inspected every 18 months in major roads, with fewer intervals in minor roads.

i. Tree Database is being established in Nparks for inventory purpose. Urban Forestry concept is applied in managing urban trees.

j. It was noted in Singapore that 60 - 70 kmh wind can begin to threaten breakage for trees in Singapore.

k. Vertical Greening is starting in Singapore. The 4 major criteria include Weather & Environment, Plant Choice, System & Media, & Water Supply. With typhoons in HK, this is yet to be seen for cost justification in its application. It may be cheaper to plant a tall tree in front instead if space is available.

After the Seminar, there was a guided tour to Hort Park & Southern Ridges to see spectacular planting & landscape features. The visit was well rewarding with knowledge & education for the participated group of around 30 persons from HK, Macau, New Zealand & Brunei.

Selected photos of the SGF visit are attached for sharing with Station Members. This trip has been memorable with over 4 Govt Depts from HK & 1 Govt Dept from Macau participating, plus participants from our public & private sectors. This is the largest group ISA HK/China has managed to call up so far to support any overseas event.

There will be a Green Thumb event in Singapore around mid-Sep this year & ISA HK/China has been invited to participate in the tree climbing competition. We shall send out our best climbers to compete as well as perhaps a noisy group of local climbers just to go there to support & enjoy. Green Thumb will be a fun-filled & lively event different from serious education of SGF. ISA HK/China will be represented by the muscular & daring for a change to cheer & jeer at the tree climbing competition. Further information will be disseminated in Station Mail upon confirmation from Nparks later.

Arborists are forever learning people & our activities have proved just that. ISA HK/China will now look forward to come to the Green Thumb in Singapore soonest.

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. (http://www.isa-arbor.com/)