Current practice dictates that trees should not be staked unless wind is a problem or the tree develops a lean. Then it can be supported with a stake and flexible guy wire that will permit the tree trunk to sway in the wind. Young trees standing alone with their tops free to move will develop stronger, more resilient trunks than those staked for several years. The stem from long term staking may in fact become thicker above the tie than below it because diameter growth increases in response to the movement of the crown. As the tree can flex only above the height of the guy wire, it is easy to snap the crown off by using the tie as a pivot.
A supported tree will initially gain height faster than the unsupported tree, but the stem will be thin and weak up to the tie and then it will taper rapidly. Normally, when a tree bends as a result of wind, root development on the windward side of the tree is increased, thereby aiding the tree in becoming stronger and eventually straightening up on its own. Recent research has discovered that the tree actually develops an oval cross section to deal with prevailing winds. This cannot occur if the tree is staked or guyed. Staking may be needed for street trees to stabilize against jostling from pedestrian traffic. Street trees are best supported with two stakes, set parallel to the curb, so that traffic and pedestrians are not hindered.
If a tree must be staked, all stakes and guy wires should be removed when the tree can stand straight on its own. A staking system is one that secures new trees up to 20 feet (6 m) tall with long stakes driven into the soil on either side of the root ball. From the stakes, a short hose covered wire or other device holds the tree in an upright position.
Every newly planted tree should be assessed independently on whether or not it should be staked. The tree is not as likely to be girdled by these attachments in one growing season, but if they are left on for too long they will girdle a tree or weaken it as indicated above. When stakes are used, the tree should be “tested” at the end of the first year by being pushed back and forth. If the tree stands upright and the trunk is rigid at the soil line, the stakes should be removed. Whatever tie material is used, guy supports will quickly cut into the bark and interfere with the movement of water and nutrients within the tree.
Staking Systems
Staking systems can vary from inexpensive wood stakes with wire or cable to very expensive manufactured staking systems. Staking systems can also vary according to the size of the tree. The common characteristic of any staking system is that it requires time to install and maintain. One system uses a unique, one stake support with a flexible tree bracing collar that allows for natural sway movement and lessens the likelihood of trunk injury. In addition, the single stake is easy for one person to install, is reusable, does not detract from the beauty of the tree, and is not a pedestrian trip hazard.
Tree bracing collars should be smooth, wide, flexible, and not abrasive in any way. One of the best attachments is made of soft nylon webbing or carpet strips attached by grommets to a stake. The old practice of using a piece of garden hose covering a cable is no longer recommended due to the damage the hose can cause to the bark. The tree bracing collars should be located within the first third the distance up the trunk.
The stakes can be made of any material but 2” x 2” lumber is the preferred favorite. To prevent damage to the root ball, stakes should be placed in the ground beyond the outer edges of the ball.
Pros of Staking:
When the new trees have abnormally small root systems that can't physically support the larger above-ground growth.
When the tree is of a substantial size.
When the stem is spindly and bends excessively when it is not supported.
When the tree is a palm, which may have a small root ball.
When the planting site is very windy and trees will be uprooted if they are not supported.
When there is a good chance vandals will uproot or damage unprotected trees.
When the soil is comprised of sand or other loose-textured material.
Cons of Staking:
Stakes detract from the desired look of the landscape.
Trees need to move without restriction from the ground up.
Staking causes some trees to break and can also restrict the flow of sugars.
Often the staking system is not adjusted properly or it is left on the tree for too long. Trunk stabilizing requires time to install, maintain, and remove.
Guying
Trunk stabilizing with guy wires has been the traditional method for stabilizing newly planted trees for centuries. It is believed that trunk stabilizing came with the trees that were lashed to the decks of early trade ships. A guying system secures new plantings by long wires running from the ground to the first third the distance up the trunk where the wire is secured around the trunk. This system is designed for trees exceeding twenty feet in height and all evergreens over 8 feet and will have guy wire systems with turnbuckles and earth anchors. Tree bracing collars made of flexible plastic or nylon tape, manufactured for this purpose, or twist braces that allow for flexibility of the tree trunk should be used instead of hose and wire. These braces are also recyclable. Often, a guy wire is too tight around the trunk and will effectively girdle and kill the tree.
Cons of guying:
Wires detract from the desired look of the landscape and often require flagging to prevent a tripping hazard.
Trees need to move without restriction from the root collar.
Guying places unnatural stress at the point where the guying materials attach to the trunk.
Often the guying material is not adjusted properly or it is left on the tree for too long.
Girdling occurs where the tree begins to grow around the offending guying materials, absorbing them into the trunk.
Trunk stabilizing requires time to install, maintain, and remove.
Biodegradable Guying System
One inexpensive guying system consists of using wire that is a soft No. 9 wire put in a 2”x18" (5x45 cm) length of carpet, creating an open loop around the tree trunk. The wire is attached to a softwood stake that is not painted or treated. The wire is applied so that the tree trunk touches the inside windward edge of the open loop, allowing the tree trunk a limited freedom of movement in almost every direction. This staking method completely breaks apart after 18 months and eventually rots away, eliminating the need for follow up maintenance.
Stapling
A below-grade system secures new plantings by the root-ball. A long “staple” is placed through the root ball to hold the ball in contact with the bottom of the planting pit and to hold the root system in place. Below-grade stabilizing replaces roots left in the nursery. When the roots are stabilized, there is improved root growth and the trunk is allowed to move in response to its surrounding conditions. Below-grade stabilizing reduces the chance that newly sprouting roots will be broken off during wind gusts. Staple manufacturers indicate that the staple can be removed after one season or if left in place, will eventually rust away. Another option is to build staples out of three pieces of wood.
Pros of Stapling:
There are no above ground obstructions and the desired look of a completed landscape is immediate.
No maintenance or disposal is required because there is no need to remove the staples.
Some below-grade stabilizers can be installed with a sledge-hammer in as quickly as 1 minute.
There is nothing to constrict the trunk; therefore, girdling, bark damage, and potential breaking from stress due to guying materials are eliminated.
The American Nursery and Landscape Association (ANLA) encourages all municipalities, landscape architects, and landscape installers to consider using root staples. Research has shown that trunk stabilization may be detrimental to a tree’s growth but when secured by the root-ball, trees flex through the length of the trunk. They develop a better overall taper and become more tolerant of wind and vandalism.
Cons of Stapling:
Unless the staple is removed after a couple of years, it will be a problem when the tree is removed. The stump grinding equipment can be severely damaged when it hits the metal staple if it has not rusted away.
Wrapping
Most trees do not need to be wrapped except in extremely harsh sites or to protect thin barked trees. If a tree comes from the nursery with a wrapped trunk, remove it after planting. If wraps are desired, they should be removed within one year. To avoid trunk girdling, do not attach wraps with wire, string, nylon rope, plastic ties, or electrical tape. If cared for and maintained properly and regularly, wrapping materials are worthwhile.
Pros of Wrapping
Many arborists think that sunscald may be prevented with white tree wraps on thin-barked trees (ex. maple, birch, cherry and beech) especially if trees are planted on southern exposures or paved areas that accumulate heat. Replanting the tree in the same compass orientation as it was in the nursery can
minimize sunscald. Some nurseries will place a dot of paint on the lower portion of the trunk on the north side of the tree. Other nurseries recommend looking at the branch diameters. The largest branches grow on the southwest side of the tree.
A wrap is useful in preventing injury during digging and transplanting
Cons of Wrapping
Gas exchange on the trunk is limited.
Moisture is retained between the wrap and the tree trunk.
Wrapping provides a habitat for insects, disease, and water damage to tree trunks.
Beneath the bark is a layer of green cortex that contains chlorophyl