Cabling and Bracing
What does that mean?
When would you use such a technique?
- Cabling and bracing are the two most common forms of structural
support for trees
- They involve installing flexible cables or rigid rods to reduce
the chances of failure of defective unions.
- cables are installed high in the tree, at least 2/3 the distance
from the defect to the crown
- rods are installed much lower, just above and/or below the
- cables are always stronger than rods because of their greater
- cables can be used alone, but bracing is always supplemented
- Other, less common forms of structural support are guying and
- There are three major uses of cabling and bracing:
- prevention: to reduce the chance of failure on a healthy
tree with structural weakness
- Example: a specimen bur oak in good condition but having
large limbs with "V-crotches"
- restoration: to prolong the existence of a damaged
- Example: a large sugar maple that lost one of its leaders
in a storm, leaving the others suddenly exposed and vulnerable to
- mitigation: to reduce the hazard potential of a tree
- Example: a picturesque multi-stemmed hickory that towers
over a picnic shelter
- Be sure to ask yourself some questions first:
- Is this a reasonable way to treat this tree, or am I just
trying to preserve a tree that is actually at the end of its useful life?
- How do I justify this expenditure on a single tree? Do
I have more pressing needs in my forest?
- Is the tree basically healthy? Is there enough sound
wood to anchor the cable?
- Do I understand that cabling is no guarantee that failure will
- Am I prepared to have the cable inspected annually, then replaced
after 7-10 years?
Tightening the eye bolt with a cable attached
How should it be done?
Where can I get more information?
- First, choose a certified arborist who is knowledgeable and
experienced in this area.
- There are many important technical aspects to correct cabling
- the strength and material of the hardware
- the arrangement of the cables (simple, triangle, box)
or rods (single, multiple, etc.)
- the location, type and size of the entries made into the tree
- Be sure to specify in writing that "All work and materials shall
be in accordance with ANSI, A300 Tree Care Standards (Part 3) -- 2000."
- Some arborists are testing a recently introduced polypropelene
cable system developed in Europe that promises to be faster and less injurious,
but it has not yet been included in the ANSI standard.
Oswald, Michael. 2000. "Cabling and Bracing." Arbor
Age, October. On the web (click here).
Lilly, Sharon. 1999. "American vs. European cabling and
bracing systems." City Trees (35:3). Also on the web
The ANSI A300 (Part 3) standards can be obtained from the International Society of Arboriculture
or from American Forests. For other
information, advice and help on this topic, call offices of your State
Urban Forestry Coordinator or University Extension service, or visit urban
forestry web sites.