Tree Cable Systems

Tree cable systems are an essential item in the preservation based arborist toolbox.  These cables are installed in the canopy at a height of 2/3 between the branch union being supported to the top of the tree, and they allow the each side of the tree to support the other. When installed to industry standard, they can reduce risk of trees with structural defects, as well as maintain high value trees where large limb failure could result in catastrophic consequences for the health of the tree.

EHS steel cable system with through bolts installed in an oak tree in Wells, Maine.

Some of the most common reasons to install cables and other tree support systems: Included bark/cracked/poorly attached branch unions (these weakly attached branch unions can be at risk of failure and therefore are often chosen to be protected), large co-dominate stems/trunks, improper tree structure and for preservation of high value trees.

If you are not familiar with the trem “included bark” it is worth looking back a a few articles to find the one where I specifically talk about this common structural problem that can result in tree failure.

A cable was installed in this large oak tree in Wells, Maine to reduce the chances of the tree failing and splitting apart at the base.

 There are multiple different forms of cable systems. The most common being the EHS (extra high strength) steel cable. This is generally paired with steel eye bolts that are installed into the center of the limb being supported. Drilling through the tree allows the limb to continue growing over the bolts and therefore eliminates the potential for girdling (when the something is wrapped around a limb, as the tree grows the item will begin to compress the vascular tissue of the tree which usually leads to decline).

The second most common system used today is the dynamic cable. These come in many forms, but they are often a synthetic fiber cable that allows unaffected movement of the tree, but is there to protect against failure in a weather event. Due to photodegradation of synthetic fibers, these systems must be inspected and replaced much more often than steel systems. Manufactures recommendation varies, but they tend to be 5-7 year lifespan.

Installing an EHS cable in a double stem sugar maple in Kennebunk, Maine.

If you have trees that have any of the features noted above, it is worth talking to an arborist to discuss your options, make sure that they are fully qualified on the subject as incorrect installation can cause catastrophic damage to a tree.

If you have trees with cables already, be sure to have an arborist inspect them annually.

Tree failure can be expensive, cable systems can be looked at as an “insurance policy” of sorts to help protect your valuable trees and property.