What does that mean?

• 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 defect
• cables are always stronger than rods because of their greater leverage
• cables can be used alone, but bracing is always supplemented with cables
  
• Other, less common forms of structural support are guying and propping
  

• 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 tree
• Example: a large sugar maple that lost one of its leaders in a storm, leaving the others  suddenly exposed and vulnerable to further damage
  
• 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 not happen?  
• Am I prepared to have the cable inspected annually, then replaced after 7-10 years?

• First, choose a certified arborist who is knowledgeable and experienced in this area.
  
• There are many important technical aspects to correct cabling and bracing
• 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 (click here).  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.