Protecting Large Branches in Mature Trees

Many homeowners are committed to the health and maintenance of their large mature trees. Trees increase property value, provide privacy, offer wildlife habitat, provide shade, and generate reductions in heating and cooling costs; as well as many people having a feeling of personal attachment to them. The last thing most homeowners want to do is remove a mature tree from their property if it’s not needed.

Tree cabling and support systems can mitigate the risk of damage or injury to your tree and maintain the many positive attributes a mature tree has to offer.

Tree Support Cabling: Why It’s Important and ANSI Standards You Should Know

Tree support cabling is a technique used to help maintain the health and stability of trees, especially those with weak or structurally compromised branches. Cabling involves the installation of flexible steel cables between branches to provide support and reduce the risk of damage from wind, snow, ice or heavy foliage. However, to ensure the proper installation and long-term effectiveness of tree support systems, it’s crucial to adhere to established standards—particularly those set by the American National Standards Institute (ANSI).

The Role of Tree Support Cabling

Tree support cabling is commonly used for trees that have structural issues like codominant stems, heavy limbs, or branches that are at risk of breaking. It can prevent these limbs from failing during extreme weather conditions, reducing the likelihood of damage to the tree itself or nearby property. Support cabling helps distribute forces more evenly, stabilizing the tree and improving its resilience against external stressors.

ANSI A300 Standards for Tree Support Cabling

The ANSI A300 standards, particularly part 7, provide guidelines for the installation and maintenance of tree support systems. These standards are used by professional arborists, as they outline the best practices for ensuring the safety, health, and integrity of both the tree and the people around it. Here are some key points covered by ANSI standards for cabling:

1. Assessment of Tree Health
Before installing any support system, ANSI A300 standards recommend a thorough assessment of the tree's overall health and structural integrity. The goal is to determine if cabling is appropriate, considering factors such as the tree’s species, age, and the presence of diseases or pests. Proper assessment ensures that the support system is used only when necessary, avoiding unnecessary installations that might interfere with the tree’s natural growth.
2. Cabling Materials
ANSI A300 outlines the materials used in cabling, recommending flexible steel cables that are strong, durable, and capable of withstanding environmental stresses. These materials should be resistant to wear, corrosion, and UV degradation. Additionally, cables should be designed to allow for the tree’s natural movement without causing damage over time.
3. Installation Techniques
The standards recommend using installation methods that minimize harm to the tree. This includes proper spacing of anchors and minimizing damage to the cambium layer (the tree’s growth layer). The installation should be performed by a qualified arborist to ensure it is done correctly and in compliance with safety standards.
4. Regular Inspections and Maintenance
ANSI A300 stresses the importance of regular inspections of cabling systems. Cables can loosen or become damaged over time, so it’s vital to inspect the system at least annually and after extreme weather events to ensure it continues to function as intended.

Tree support cabling is an effective way to protect trees with structural vulnerabilities, but it must be done according to ANSI A300 standards. These guidelines ensure that cabling systems are installed safely, using the right materials and techniques, and that ongoing maintenance keeps the system functioning properly. If you're considering support cabling for your trees, it’s important to consult with an ISA Certified Arborist who can ensure compliance with ANSI standards and recommend the best solution for your trees’ needs.