ISA HK/China --- Poor nursery stocks planted in Sheung Shui

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Dear Station Members,

The attached photos show the quality of a recent tree planting in Sheung Shui. Please kindly excuse this Station for not giving the exact location because Station Mail only provides comments based on facts with our professional knowledge & without bias, & is never meant to attack anybody.

The tree species is Melaleuca leucadendron with a naturally strong Excurrent (Strong Central Leader) character. If grown in open ground, this tree would develop a straight Central Leader with a pyramidal shape in a predictable form. This tree can be easily grown in a nursery without much experience & would develop into good quality with minimum training. Even if they are neglected or planted too closely in our China nurseries, owing to their vast numbers in production, selection of quality trees is still possible if only 1 out of a hundred is to be picked. The Station Manger does not know of any difficulties in finding a small amount of quality Melaleuca trees in China nurseries in his 23 years of buying trees in China.

For Young Trees (below 100mm DBH) of this species as quality Nursery Stocks, we would be looking for:

1. Central Leader --- A strong & single trunk to grow vertically from base to tip. No double or multiple stem leaders. No Included Bark.

2. Taper --- A noticeable Taper thickening from base & gradually narrowing to tip for maximum wind resistance.

3. Live Crown Ratio --- A minimum of 50% of Live Crown Ratio (Ratio of height of foliage against the total height of a tree) for
adequate foliage to produce carbohydrate & better wind resistance. Trees get their food from Photosynthesis, not fertilizers.

4. Large Wound / Topping --- No mechanical wound of any kind larger than 50mm in diameter & no Topping, for decay prevention & future tree architecture.

5. 10 x DBH Rootball diameter --- The larger the rootball, the better is the survival chance & speedy recovery. BS 4043:1989 requires a 10 x trunk diameter rootball, so is recommended by ISA practices.

Above are just some minimum requirements for a Nursery Stocks grown to international standards.

By studying the pictures attached, would any of the trees shown meet the above criteria, say, only for above-ground requirements? If not, it is bad luck for all of us because they are already there, maybe waiting to be handed over for on-going maintenance.

Good Nursery Stocks is the fist step to success in any landscape & poor Nursery Stocks will lead to excessive maintenance & possible failures in future. If trees are not selected, planted, maintained & inspected properly & regularly, they would become more of a liability to the public rather than an asset, as has been shown in so many tree failures reported in the past.

Station Mail is circulated to many overseas countries nowadays. Would any of our overseas partners accept such trees to be their Nursery Stocks for use in their landscape? If so, we would like to learn of their valuable experience indeed for why.

Some of our Mature Trees have become time bombs in our territory. Is this how they were started in the first place?

best regards,

Sammy Au
Station Manager