If installed properly, most trees and shrubs will not need support to grow straight and strong. Past practice nearly always included staking or guying transplants, especially trees, but that has now been proved to be unnecessary and often detrimental. Staking and guying have been shown to cause effects such as these in transplanted trees:
• Damage due to girdling from the tie materials
• Bent growth away from the stake
• Increased stress on the trunk at the point of attachment to the staking materials
• Weak wood development from the staked support downward toward the base of the tree
• Reduced root production
• Reduced trunk taper
The initial reason for staking and guying was to prevent the transplanted tree or large shrub from moving, usually due to the wind. Recent research has shown that transplants actually benefit from some movement, as it stimulates better root growth. In general, trees that are six feet or less in height or less than one inch in caliper (trunk diameter measured six inches above the ground) will not require staking to support them. Only trees that are very large, or have weak trunks, or are being transplanted in high wind locations should be staked or guyed. Additionally, trees that are transplanted in densely populated urban areas where vandalism is a potential problem or where mowing is done
figure 10-10. Metropolitan communities often use metal grills to protect recent transplants. (Delmar/ Cengage Learning. Photo by Jack Ingels.)
by workers who are insensitive to the care of new plantings may find staking or guying to be necessary safeguards. If it is to be done, then here is how to do it.
Staking uses one, two, or three wood or metal stakes driven into the ground parallel to the trunk of a tree and down into solid, undisturbed soil. The stakes should be long enough to extend about 8 inches above their point of attachment to the tree. The point of attachment should be about 6 inches above the highest point at which the trunk can be bent by a strong wind yet return to its upright position.
The stakes can be attached to the tree in several ways. The traditional way has used heavy wire looped through links of hose at the point of contact with the tree, then attached to the stakes and tightened by twisting the wire at its center until the desired tautness is attained. Although still used, the wire and hose link technique has been shown to cause injury to some plants when repeated movement by the wind causes the hose coverings to wear away the bark. That may result in a girdling condition. Currently gaining favor and acceptance are commercial ties that replace the wire and hose links. Made of tough, weather resistant webbing, the ties are flat and wider than wire, so they do not gouge the bark. They also have a slight elasticity, providing a more flexible support
to the plant than the wire and hose technique. Since the webbing material cannot be twisted like wire, it should be applied with a figure-eight loop between the stake and the tree to allow for flexibility.
Using a single stake is most appropriate when the intent is to prevent a plant from being pushed off center by a strong prevailing wind. In such a case, the stake is positioned on the upwind side of the plant. For the stabilization of small trees, two stakes are often used, (Figure 10-11A). They are placed on opposite sides of the trunk and attached to the same point on the tree. Securing the trunk at additional levels along the stakes should be avoided because it creates additional stress points when the tree moves in the wind. However, the two stakes can be reinforced at the base with a wooden cross tie to prevent their wobbling and coming loose. On windy sites, three stakes may be used for added stability. Three stakes also offer greater protection from mower damage and may dissuade vandals.
Guying is the stabilization of large trees and multistemmed plants using the hose wrapped wires or strapping material described above, but attached to anchoring devices that are driven into the undisturbed soil. If stakes are used as the anchors, they should be driven at a 45-degree angle to the ground surface and point toward the tree. If driven to point away from the tree, they can become loosened over time, (Figure 10-11B). Usually three guys are needed to provide the desired stability. For exceptionally large trees, underground anchors, termed deadmen, may be used to ensure that the guys do not work loose. Support wires can be twisted to the desired tautness or turnbuckles installed to accomplish the same thing. For safety, all exposed wires should be flagged with colorful tape so that no one trips over them. Whether a plant is staked or guyed, all apparatus should be removed after one year to avoid injury and prevent girdling.
When only a single stake is used When two stakes are used, they are
it shou|d be p|aced on the upwind side. placed on opposite sides and attached
at the same point. A wide, flexible material should be used to avoid cutting into the trunk. Stakes are removed after one growing season.
figure 10-11A. Bracing the tree by staking (Delmar/Cengage Learning)