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Tree Supplemental Support Systems: Bracing and Cabling

Healthy, mature trees are not just natural wonders but also valuable assets to your property. They can increase property value, reduce your energy bills, and help with water absorption. However, they may occasionally require additional support to ensure their structural integrity and safety. In this blog post, we will explore two essential tree supplemental support systems: bracing and cabling. We will discuss the differences between static and dynamic cabling systems, the pros and cons of each, when to use bracing in addition to cabling, the distinction between these systems, and the tools and materials needed for their installation.

Cabling a River Birch

Why Supplemental Support Systems Are Necessary:

Mature trees can develop structural weaknesses due to factors like age, weather, disease, or poor pruning practices. Supplemental support systems help mitigate these weaknesses, prolong the life of the tree, and reduce the risk of limb failure, which can be hazardous to people and property. In addition to mitigating hazards, supplemental support systems can reduce the risk of disease and pest problems that can impact tree health if there is an open wound from a limb failure. Large open wounds from limb failures can be extremely difficult for a tree to seal and compartmentalize, leading to a potentially life long exposed defect.

Large exposed defect from limb failure

Static vs. Dynamic Cabling Systems:

1. Static Cabling:

- Definition: Static cabling involves using non-moving hardware, such as steel cables and threaded rods, to support tree limbs. These systems provide continuous, fixed support.

Opinion: Static cabling is to be only used for critical situations where movement is not allowed, e.g. a tree has codominate stems and the branch union has started to split.

- Pros: High stability, long-term support, minimal tree sway, effective for heavy branches, and typically requires less maintenance.

- Cons: Limited flexibility in accommodating tree movement, may not address dynamic forces during storms, and can lead to compartmentalization (decay) if not installed correctly. The procedure is invasive, which requires drilling. The risk for spreading decay and disease is higher than that of a dynamic system. This method also requires more equipment and heavier materials.

Steel Cable and Lag "j"-bolts with dead end grips

2. Dynamic Cabling:

- Definition: Dynamic cabling utilizes flexible components, such as synthetic fiber ropes, to allow for some tree movement. It mimics the natural swaying of a tree during wind and storm events.

Opinion: Dynamic cabling has great strength but allows for tree movement and should be used to prevent a tree from exceeding its load potential to prevent a failure. Think of it as an insurance policy for a tree.

- Pros: Reduces the risk of limb failure during storms, promotes healthy dynamic response, and minimizes the risk of compartmentalization. Non invasive, does not require drilling.

- Cons: Requires regular inspection and adjustment, shorter lifespan of materials, and may not be suitable for all tree species or situations. May not offer as much strength as a static system especially as materials degrade.

Cobra dynamic cabling system installed on a white oak with a codominate stem. The larger part in the middle is a shock absorber that can be inserted into the synthetic fiber rope to assist in load dissipation.

When to Use Bracing in Addition to Cabling:

Bracing systems involve installing hardware within a tree's trunk or limbs to support weak crotches. They are typically used in combination with cabling systems when there is a risk of splitting or excessive limb movement. Bracing adds stability and helps prevent limbs from pulling apart.

Differences Between Bracing and Cabling Systems:

- Bracing: Provides support within the tree's structure, helps to reduce the risk of splitting, and is often used for branches or stems with included bark

- Cabling: Uses cables or ropes to connect limbs or branches, reducing the risk of limb failure due to excessive weight or structural weaknesses.

Tools and Materials Needed for Both Systems:

- Cabling and bracing hardware (such as threaded rods, cables, or synthetic ropes).

- Appropriate anchors and connectors.

- Drills and associated drilling tools.

- High-quality tree limb protectors to prevent damage during installation.

- Protective gear for the arborist.

- Inspection tools like binoculars for regular maintenance.

References to Industry Standards:

- ISA Study Guide: The International Society of Arboriculture (ISA) provides valuable resources and guidelines for arborists, including their Certified Arborist Study Guide.

- ANSI Standards: Arborists often follow ANSI A300 standards for tree care operations, which include guidelines on cabling and bracing.

- BMPs (Best Management Practices): Arborists adhere to BMPs established by organizations like the Tree Care Industry Association (TCIA) to ensure the highest standards of care and safety in the industry.

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