Support protection

Tree Support and Tree Support and Protection SystemsProtection Systems

Mark WachterMark WachterResource ForesterResource Forester

Missouri Department of Missouri Department of ConservationConservation

Certified Arborist #MW-4340ACertified Arborist #MW-4340A

OverviewOverview

Arborists’ Certification Study GuideArborists’ Certification Study Guide Cover chapter 9 objectives and key Cover chapter 9 objectives and key

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IntroductionIntroduction

Cables or braces are installed in Cables or braces are installed in trees to provide extra support by trees to provide extra support by limiting the movement of limbs.limiting the movement of limbs.

Any time hardware is installed in a Any time hardware is installed in a tree, there will be wounding and the tree, there will be wounding and the risk of decay.risk of decay.

Hazardous trees cannot be made Hazardous trees cannot be made safe by the use of cables.safe by the use of cables.

Cable InstallationCable Installation

Cables are installed in trees to limit Cables are installed in trees to limit movement of limbs judged to have a movement of limbs judged to have a week connection or to support heavy week connection or to support heavy limbs by connecting two or more limbs limbs by connecting two or more limbs together.together.

Additional support may be needed due to Additional support may be needed due to split or decayed crotches, crotches with split or decayed crotches, crotches with included bark, or inherent danger of included bark, or inherent danger of weak-wooded trees.weak-wooded trees.

Cable InstallationCable Installation

Before installing cables or braces, Before installing cables or braces, the tree should be properly pruned to the tree should be properly pruned to remove hazardous limbs and to remove hazardous limbs and to reduce the weight of the limbs to be reduce the weight of the limbs to be cabled.cabled.

Splits such as this may be candidates for support with a cable and brace rod.

Splits such as this may be candidates for support with a cable and brace rod.

Heavy limbs may be candidates for cabling.

Cabling HardwareCabling Hardware

Two cable typesTwo cable types 7-strand, common-grade galvanized7-strand, common-grade galvanized

More bendableMore bendable Extra-high-strength (EHS)Extra-high-strength (EHS)

Much stronger, but less flexible Much stronger, but less flexible Sizes of 3/16-inch to 3/8-inch diameterSizes of 3/16-inch to 3/8-inch diameter

Cabling HardwareCabling Hardware

Dead-end hardware (one end exposed)Dead-end hardware (one end exposed) Lag eyeLag eye

Anchor with a closed eyeAnchor with a closed eye Lag hook, or J-hookLag hook, or J-hook Sizes of 5/16-inch, 3/8-inch, ½-inch, and Sizes of 5/16-inch, 3/8-inch, ½-inch, and

5/8-inch5/8-inch Refer to ANSI A300 for hardware Refer to ANSI A300 for hardware

limitationslimitations

Left and right lag hooks.

Cabling HardwareCabling Hardware

Lag hooks are installed by screwing Lag hooks are installed by screwing into a pre-drilled hole that is smaller into a pre-drilled hole that is smaller in diameter than the lag. in diameter than the lag.

Drill hole 1/16-inch to 1/8-inch Drill hole 1/16-inch to 1/8-inch smaller than the lag.smaller than the lag.

Cabling HardwareCabling Hardware

Dead-end hardwareDead-end hardware Works good on small limbs with hard Works good on small limbs with hard

wood.wood. Do not install in limbs greater than 8 to Do not install in limbs greater than 8 to

10 inches in diameter. 10 inches in diameter. Do not install in limbs with decay.Do not install in limbs with decay. Must seat the full length of the threads.Must seat the full length of the threads.

Cabling HardwareCabling Hardware

Through-hardware (both ends Through-hardware (both ends exposed)exposed) Eye boltsEye bolts Threaded rods with amon-eye nutsThreaded rods with amon-eye nuts

Threaded rod with amon-eye nut (top); eye bolt (bottom).

Cabling HardwareCabling Hardware

Through-hardwareThrough-hardware A hole 1/16-inch to 1/8-inch larger than A hole 1/16-inch to 1/8-inch larger than

the hardware is drilled through the limb the hardware is drilled through the limb to be cabled.to be cabled.

Eye bolt or threaded rod is installed with Eye bolt or threaded rod is installed with a round washer and nut on the outside a round washer and nut on the outside end.end.

On very thick bark, the bark should be On very thick bark, the bark should be chiseled away to countersink the washer chiseled away to countersink the washer against the sapwood.against the sapwood.

Cabling HardwareCabling Hardware

WashersWashers Eye bolts and threaded rods must be Eye bolts and threaded rods must be

anchored with washers and nuts.anchored with washers and nuts. Heavy-duty round washers are Heavy-duty round washers are

recommended.recommended.

Cabling HardwareCabling Hardware

ThimblesThimbles Must be used when attaching cable to Must be used when attaching cable to

anchoring hardware.anchoring hardware. Purpose is to protect cable from Purpose is to protect cable from

excessive wear.excessive wear.

Cabling HardwareCabling Hardware

Dead-end gripsDead-end grips Used to attach EHS cable to hardware.Used to attach EHS cable to hardware.

Cabling Tools and Cabling Tools and EquipmentEquipment

Come-alongCome-along Brings two branches together.Brings two branches together.

Cable gripCable grip Used to pull cable to proper tension.Used to pull cable to proper tension.

Cable aidCable aid Used to spread open thimbles, to tighten Used to spread open thimbles, to tighten

lags, and help wrap dead-end grips onto lags, and help wrap dead-end grips onto the cable.the cable.

Cabling Tools and Cabling Tools and EquipmentEquipment

Ship augerShip auger Works well in green wood and pulls Works well in green wood and pulls

shavings from hole.shavings from hole.

Attaching Cable to Attaching Cable to HardwareHardware

Eye spliceEye splice Used for 7-strand, common-grade cable.Used for 7-strand, common-grade cable.

Cable clampsCable clamps Alternative to using an eye splice.Alternative to using an eye splice.

Installation TechniquesInstallation Techniques

Cables should be installed at least two-thirds the distance from the crotch to the branch tips.

The cables should be installed perpendicular to an imaginary line that bisects the crotch.

The hardware should be installed in direct line with the pull of the cable.

The hardware should be installed in direct line with the pull of the cable.

Cabling systems.

Hardware installed in trees should be no closer togetherthan a distance equal to the diameter of the limb.

Only one cable should be attached to each anchor.

Much of the holding power comes from wood that formsafter installation.

Installation TechniquesInstallation Techniques

Anchors should not be installed into Anchors should not be installed into decayed areas.decayed areas.

The installation of cables in a tree The installation of cables in a tree represents an ongoing responsibility.represents an ongoing responsibility.

Cables must be checked annually.Cables must be checked annually.

Nonrigid Support SystemsNonrigid Support Systems

BracingBracing

Used to reinforce weak or split Used to reinforce weak or split crotches, or to strengthen decayed crotches, or to strengthen decayed areas. areas.

Bracing is used in combination with Bracing is used in combination with cabling, not as a substitute.cabling, not as a substitute.

BracingBracing

Two types of steal rodsTwo types of steal rods Lag-threaded rodsLag-threaded rods

Can be installed as dead-end hardware.Can be installed as dead-end hardware. Drill hole 1/16-inch to 1/8-inch smaller than diameter Drill hole 1/16-inch to 1/8-inch smaller than diameter

of rod.of rod. Advantage is threaded rod itself provides support.Advantage is threaded rod itself provides support.

Machine threaded rodsMachine threaded rods Used in soft-wooded trees, or decayed wood.Used in soft-wooded trees, or decayed wood. Drill hole 1/16-inch to 1/8-inch larger than diameter Drill hole 1/16-inch to 1/8-inch larger than diameter

of rod.of rod.

Threaded rod with nuts and washers.

BracingBracing

To support a crotch that is not split:To support a crotch that is not split: A single rod is installed above the crotch.A single rod is installed above the crotch. Place 1 to 2 times the branch diameter Place 1 to 2 times the branch diameter

above the crotch.above the crotch. Additional braces may be installed below the Additional braces may be installed below the

crotch, if necessary.crotch, if necessary. To support a split crotch:To support a split crotch:

Install rod below crotch and through the Install rod below crotch and through the split.split.

GuyingGuying

Guying of trees tends to be permanent Guying of trees tends to be permanent because tree will not produce the because tree will not produce the necessary roots or wood to support itself.necessary roots or wood to support itself.

Ground anchors should be placed no Ground anchors should be placed no closer to the trunk than two-thirds the closer to the trunk than two-thirds the distance from the ground to the lowest distance from the ground to the lowest attachment in the tree.attachment in the tree.

Guys should be attached about two-thirds Guys should be attached about two-thirds the height of the tree.the height of the tree.

Guys can present a hazard to pedestrians.Guys can present a hazard to pedestrians.

Lightning ProtectionLightning Protection

Some trees more likely to be struck:Some trees more likely to be struck: Trees alone in an open landscapeTrees alone in an open landscape Tallest trees in an areaTallest trees in an area Trees on a hillTrees on a hill

Lightning ProtectionLightning Protection

Which trees to protect?Which trees to protect? Historic treesHistoric trees Trees of great economic valueTrees of great economic value Large trees within 10 feet of a structureLarge trees within 10 feet of a structure Trees in recreational areas, golf coursesTrees in recreational areas, golf courses

Protected trees are not intended to Protected trees are not intended to directly protect people from lightning directly protect people from lightning and are not considered safe havens and are not considered safe havens in storms.in storms.

Lightning ProtectionLightning Protection

A lightning protection system A lightning protection system consists of a series of copper consists of a series of copper conductors that extend from the top conductors that extend from the top of the tree, down the main braches of the tree, down the main braches and trunk, and out beyond the tree and trunk, and out beyond the tree underground where they are underground where they are grounded.grounded.

Lightning ProtectionLightning Protection

Air terminalAir terminal Copper or bronze point located near top Copper or bronze point located near top

of treeof tree Main conductorMain conductor

Copper cable connected to air terminal Copper cable connected to air terminal and running down main branch and the and running down main branch and the trunk.trunk.

Attached at regular 3 feet intervals with Attached at regular 3 feet intervals with approved attachments.approved attachments.

Lightning ProtectionLightning Protection

Main conductorMain conductor Support systems (cables) should be Support systems (cables) should be

connected to lightning protection connected to lightning protection system.system.

Conductor cable should extend out from Conductor cable should extend out from the tree and be buried 8 to 12 inches the tree and be buried 8 to 12 inches below ground. below ground.

System still functional if tree grows System still functional if tree grows around conductor as long as there is no around conductor as long as there is no break in the conductor.break in the conductor.

Lightning ProtectionLightning Protection

Ground rodGround rod Conductor cable attached to copper Conductor cable attached to copper

ground rod that is 10 feet long and ½-ground rod that is 10 feet long and ½-inch diameter.inch diameter.

Ground rod should be driven to a depth of Ground rod should be driven to a depth of 10 feet.10 feet.

In dry, sandy, or rocky soils, the cable In dry, sandy, or rocky soils, the cable should be forked to several ground rods.should be forked to several ground rods.

For soil with less than 2 feet of depth, use For soil with less than 2 feet of depth, use a ground plate.a ground plate.

Lightning ProtectionLightning Protection

All hardware should be approved by All hardware should be approved by the National Fire Protection the National Fire Protection Association or the Lightning Association or the Lightning Protection Institute.Protection Institute.

In dry, sandy, or rocky soils, the cable should be forked to multiple ground rods.

Ground plate.

SummarySummary

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