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 There is an ongoing debate in the American tree care industry. Steel is the traditional method and it has its advantages, but today's modern fabric and synthetic cabling provides too many benefits to overlook.
Cabling is most often used to support a tree canopy that has a structural defect, such as a crack. With the higher branches moving in the wind, you get significant leverage on the crack, making it worse. Cabling stops the leverage by securing the upper branches. You want to go two thirds above the defect to put in the support system in one of several patterns.
Back to rigid versus dynamic... steel is so rigid that it can actually make living wood unproductive. That is, it allows so little movement that it inhibits healthy tree growth. Dynamic (elastic) materials allow movement in the tree. It's a well-known fact that an unstaked sapling will gain a much greater diameter than a staked sapling. That's partly because the tree's movement helps it grow. As a tree moves in the wind it builds more wood. The other disadvantage to steel is that its shock load is more severe than the springier rope. Snapping wire cable against metal anchor hardware isn't often healthy for branches.
A comparison
Dynamic systems are recommended for:
• Horizontal installations between limbs of young to middle-aged trees with sound crotches (no included growth).
• Species known for poor compartmentalization of wounds.
• Trees with leggy structure determined to experience significant flexibility to wind and ice.
• Hollow limbs where drilling is likely to accelerate decay or not provide sound anchorage for invasive hardware.
Static cables are recommended for:
• Horizontal installations between limbs of young to middle-aged trees with obvious bark inclusion or braced crack.
• Species known for good compartmentalization of wounds.
• Stout, tapered trees known to have limited movement in wind and ice.
• Situations requiring minimal movement (above bracing).
• Vertical support of horizontal limbs.
And there are three basic kinds of tree "orthopedics":
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Cabling- this is up in canopy of a mature tree. It can involve multiple applications or just one.
• Guying- this is used on a healthy tree whose roots are not holding.
• Bracing- threaded rod is put through the wood of the defective part to hold a split together.
To find a qualified arborist in your area visit this link on the International Society of Arboriculture's website and search by name or location.
http://www.isa-arbor.com/findarborist/findarborist.aspx |
