street-trees

Tree Cabling Services

Cabling is the process of wrapping tree branches with rope to help support the branch and keep it from breaking. This blog post will discuss how to cable a tree, what you’ll need, and when you might want to cable your trees. 

What You’ll Need: A large piece of natural fiber rope; gloves (optional); work gloves (optional)   What To Consider Before Cabling Your Tree: If there are any diseased limbs on your tree that could cause damage if they break or fall on someone, cabling them can prevent catastrophic failure in high winds. 

If no disease is present on the limb, but the limb has been weakened by construction activity near it, cabling may still be warranted for safety reasons. 

Tree cabling is a technique that has been used for centuries to help trees grow. It’s easy to do, and it can be done by anyone with an inexpensive roll of wire.  

To cross two branches together at their small end, use your hands or pliers to twist the wire around them in opposite directions until they are tight against each other. 

The result will be a crossing pattern that looks like an “X” on the branch- where the branch meets the trunk, you should see two wires crisscrossing one another. This will support both limbs as they grow, providing stability and preventing high winds or ice storms breakage.

An Introduction to Tree Cabling

Tree cabling is a lesser-known preservation technique utilised by professional Arborists to provide support to trees that may be prone or at risk of failure. There are a number of different support systems for tree care applications, but tree cabling is the most common and widely used within the tree care industry. 

Cable systems are either static (steel) or dynamic (rope) systems that are installed in the upper canopy to add support and reduce risk. Again, a professional Arborist evaluation and recommendation is best to determine what your tree needs for overall health and longevity.

A tree support system’s main purpose is to provide additional support or limit the movement of a tree or tree part. They do not provide primary support to a tree. Typically, a cable system is used to support weak unions and long heavy limbs. 

Often times, limbs or trees are cabled to reduce the risk posed to people or property. A tree cable system can be arranged in various configurations to best suit the trees support needs. Thus, they act as an extra measure of safety to preserve and maintain trees in our urban environment but not guarantee safety.

There are two types of cable systems: static and dynamic. Static systems are composed of steel cables and hardware. Dynamic systems are composed of non-invasive, rope-like materials. Steel (static) systems were traditionally used before the introduction of dynamic systems. 

Steel cable is oftentimes used in very failure-prone applications where system longevity and strength are necessary. Dynamic systems also provide great, high strength support and risk reduction in trees. 

The science behind dynamic systems is to allow for more natural movement in the tree while providing enough support in the canopy to reduce the risk of failure. But, again, an Arborist can best determine what type of system should be used, depending on the trees needs and risk.

Tree cable systems need to be periodically inspected by an Arborist. Scheduling inspections and follow-up maintenance on tree cables are important. Regular maintenance of a tree cabling system will help maintain its effectiveness and durability. Tree cable systems are designed to be a long-term benefit to the tree’s health. The length of time between maintenance should be determined by your arborist but should not normally be any longer than 5 years.

Can My Tree Benefit From Tree Cabling Services?

Trees are natural living things that can grow unpredictably or suffer from damage or growth defects. While many problems can be solved with proper tree trimming, problems with larger trees, such as a split trunk or a large branch that is growing at an awkward or dangerous angle, may need a little extra help to avoid removal. This is where tree cabling comes in.

Tree cabling, also known as tree bracing, is the installation of flexible, steel strand cables to stabilise the tree and reduce stress damage from high winds and the heavyweight of snow, ice or foliage. In addition, the cables work to improve the tree’s longevity by strengthening weak branches or limbs, so they are able to withstand severe weather.

In What Instances Would My Tree Require Cabling? 

  • An Open Wound  an open wound in a branch or trunk can make the tree vulnerable to harmful diseases and fungi;
  • Codominant stems – 2 or more main stems (or “leaders”) that are about the same diameter and emerge from the same location on the main trunk. As the tree grows older, the stems remain similar in size without any single one becoming dominant; The junctions between codominant stems can be the weakest part of a healthy tree.   Because of this, these trees pose a higher risk of failure. In addition, multi-stemmed trees are susceptible to breakage under the stress of severe weather. 
  • Damage Control – To protect your family and property by reducing the chance of limb failure to an otherwise healthy tree. Also, to preserve the appearance of the tree. If a tree loses a major limb, it could appear lopsided for the rest of its life. 

The tree cabling process involves drilling holes in the branches or trunk of the tree. The arborist then inserts a cable through the hole and secures it to keep the connection tight.  You may be concerned that your tree will look unsightly, but in fact, cabling is very subtle and, in most cases, almost unnoticeable. 

Tree Preservation – The How’s And Why’s Of Cabling

The wonderful thing about trees is that they are all unique, no tree is the same, and they all grow in weird and wonderful ways. The downside is that some trees can form weak unions/attachments or have to overextend limbs because they are reaching for the light. 

This can be of concern in an urban environment as they pose a potential threat to people and property. On the other hand, trees are aesthetically pleasing and provide added value to a city such as Vancouver. Therefore, preservation is an important part of tree care.

Several methods are used to help preserve trees by using supplemental support systems, such as cabling, bracing, guying and propping. This article focuses on cabling and provides an insight into one of the cabling techniques we use.

Quite often, our clients ask if cabling is where you wrap the cable around the tree. They are concerned it may look unsightly and are unsure of how it actually works. In fact, cabling is very subtle and, in some cases, almost unnoticeable. The cables are installed in the canopy and are not wrapped around the tree but stretch individually from one limb to another, as seen in the image below.

Why Do We Install Cables?

There are three main reasons why we would install a cable or supplemental support system.

  • Prevention – to reduce the chance of limb failure on an otherwise healthy tree that has potentially weak unions/crotches
  • Preservation – to preserve the existence of a damaged or weak tree for its amenity or aesthetic value
  • Protection – to mitigate the chance of failure in a potentially hazardous tree or one which poses a high risk, e.g. if it is located over the property of a frequently populated location like a park bench or footpath.

The most common cable installation is the simple or direct cable, one cable between two limbs. However, sometimes a tree will require more than one cable.

In the simplest form, cabling is essentially a single cable which is installed directly into one limb of a tree and runs to another limb. The cable reduces (but should not restrict) movement and stresses the weak point and helps mitigate the risk of failure.

The Cable Installation Process

tree-sky

The first step is for a professional arborist to assess the tree and determine the most appropriate hardware.

Several different types of wire cabling devices can be used. We are using an extra high strength cable with a Rigguy Wire Stop system in this particular process.

Once the arborist assessment and recommendations have been given, the climber accesses the tree and locates a position at least 2/3 between the point of weakness and the branches’ end. 

The point of installation is inspected to ensure that the wood is structurally sound to hold the hardware and that it is solid and large enough to provide adequate support. It may also be necessary to carry out some end weight reduction on the limbs by selectively pruning some of the branches to help reduce the weight and stress on the weak point.

A hole just bigger than the cable is drilled directly through both stems. The cable is cut to length and thread through the holes. The cable’s pull must be in direct line with the weak point to provide the most amount of structural support.

A “come along” (as seen in the image below) is a pulley system which is connected to the two stems, and when it is pulled tight, it brings the two stems closer together so that the cable can be set to the correct tension.

The Rigguy cabling system utilises a cone-shaped wire stop, which eliminates the need for larger, more cluttered hardware and can be used in more applications as it is secured on the outside of the limb.

One end of the cable is set, and the wire stop is fully installed. Then, the come-along is engaged, and the second end of the cable is temporarily set so that the come along can be released and the cable can be checked for the correct tension.

The cable should be be just taught, not too slack and not too tight. If the cable is too tight, it may put excessive stress on the wood fibres, resulting in more damage at the defect or causing the hardware to pull out. 

Equally, if the cable is too slack, it will not be performing its job in reducing movement and stress in the limbs. The tension can be readjusted by engaging the come along and temporarily resetting the wire stop. 

Once the arborist is happy with the tension, the wire stop can be fully set and the finishing cap installed. The finishing cap covers the sharp wire ends are provides a more finished appearance. This system conforms to the ANSI A300 standards.

The cable is now fully installed, and the job is complete. In order to be effective, the cable should be checked by a qualified arborist on an annual basis to ensure there is no damage and that it is still set at the correct tension.

The junctions between codominant stems are often considered the weakest portion of a healthy tree. Support may be needed because split or decayed branch unions, or those with included bark, may pose a higher risk of failure. Multi-stemmed trees are susceptible to breakage under wind stress or the weight of accumulated ice or snow. Branches that pose a potential threat to property or people may be suitable for cabling.

Guide to Cabling Trees

“Cabling” is the use of cables to stabilise an established tree growing in a manner that is not sustainable if left uncorrected. Cabling is often employed by arborists or other skilled tree service professionals to save a specimen tree. If cabling is not done properly, girdling can result; that is one reason why cabling trees are not considered a task for untrained homeowners to do on their own. An arborist will know where and how to position the cables properly.

Cabling is sometimes used to save a tree with a split trunk, for example, without cabling, such trunks will eventually be torn apart. Another use of cabling is to support a large branch that is growing at an awkward angle. In the latter case, the operation is undertaken as a preventive measure.

When such an operation is called for, it can be performed with a variety of goals in mind, such as:

  • To save the tree’s health (a compromised trunk or branch is an “open wound” that invites harmful fungi into the insides of your specimen).
  • To preserve its appearance (a tree that has lost a major limb may forever afterwards appear lopsided).
  • If it is a large tree located right near home, cabling could be necessary in order to keep a large branch from falling on the house, thereby causing property damage.
  • If a large, unstable branch is hanging over a walkway, it poses a risk to anyone using the walkway. This includes you and your family and guests―who could sue you for injuries should the branch ever fall on them.

How Cabling Is Done

tree-image

Cabling is achieved by drilling holes in the trunk or branches of the tree in question, into which the arborist will insert the cable. The cable is secured so as to keep it tight. Do not confuse cabling trees with staking trees, which is an operation that involves anchoring the tree to the ground. Support in cabling, by contrast, occurs totally above the ground.

Moreover, tree staking provides temporary support, while cabling is meant to provide stability over the long haul (often for the rest of the tree’s life). For example, a young tree (or “sapling”) may be staked in order to keep it from starting out its life crooked; as soon as it is successfully established, the “training wheels” (that is, the staking equipment) are removed. 

By contrast, if a tree has been cabled because one of its branches is growing at an awkward angle, most likely, that wire will stay there permanently. This is because the angle will always be unsustainable (on its own), so there would be little reason to remove the supporting wire.

Guying” is yet another technique used to stabilise trees and can be thought of as a cabling method in which the cable is anchored to the ground (as in tree staking) or to another tree.

Signs You Need Tree Cabling

  • Tree Cracks: Cracking or splitting in the trunk of your tree is a sign of a potentially serious structural issue and may require a support system. If you notice a crack, call an arborist to check it out.
  • V-Crotch/Co-Dominate Stems: Co-dominant stems are two or more stems that grow upward from a single point of origin. They usually create the image of a “V”, hence the name V-Crotch. As the tree’s branches grow, V-Crotches become weak spots in the tree. As a result, V-crotches are likely to split and cause the tree to fall.
  • Leaning Tree: Trees normally have a little lean-to them.  A tree trunk curves because of the tree’s ability to adapt over time to the changing availability of sunlight. The tree’s root system will grow to accommodate this off-centre weight distribution.  However, if a tree suddenly begins to lean, starts leaning after a storm, or if the soil around the tree is cracked/heaving, your tree may have a structural issue that requires tree cabling.

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