Cable Bracing for Trees

Definition and Purpose

• Not to be confused with bracing, which is a method of stabilizing trees with steel rods, cable bracing is a method of supporting limbs of trees with steel cables or synthetic-fiber systems. More commonly known as tree cabling, the method is intended to provide tree limbs with supplemental support and even limit their movement. This method is most commonly applied to trees that have large, heavy limbs or sub-trunks that are prone to breakage.

Materials and Methods

• Traditional materials include cables, nuts and washers, nut eye bolts, J lags, drills, drill bits and grips. Cable types are ranked by grade and include common grade tree cable, extra high-strength tree cable and stainless steel aircraft cable. Four cabling methods, or systems, are used to support trees: hub and spoke, direct, triangular, and box. For maximum support, the triangular method is most commonly used. For minimum support, the box method is used.

Standards

• The American National Standards Institute has established standards for arboriculture and safety. The ANSI A300 standards include seven sections that specifically cover tree management. These sections are pruning, fertilization, tree support and cabling, lightning protection systems, tree management during site planning, transplanting and integrated vegetation management. The safety standards are covered in ANSI Z133.1-2006. A revision of ANSI Z133 is expected to be released in fall/winter 2011.

Certifications

• Certification and credentials are provided by the International Society of Arboriculture. There are four levels of certification: ISA certified arborist, tree worker, specialist and master arborist. Although ISA-certified arborists are the bottom tier, they have three years of experience and have passed examinations covering general arboriculture. As described by the ISA, board-certified master arborists are professionals who have "reached the pinnacle of their profession" and "obtained other prerequisities, or "points" defined by ISA."

Considerations

• Though it is tempting to apply cabling to a tree yourself, experts recommend that you hire a professional. Pruning and cabling a tree yourself can not only have consequences that are detrimental to the tree, but to your property as well. If the cabling is improperly applied, the tree may die. That would lead to further problems, such as rotten or brittle limbs and weak trunks. You can hire a professional through a database of certified and trained arborists provided by the International Society of Arboriculture.