To Stake or Not to Stake?
As we drive across Iowa looking at new tree plantings, we can conclude that tree staking may be the tree care practice which is least understood and often not used to the optimum benefit of the tree.
Occasionally, new tree plantings may require staking to protect and/or anchor the tree. Staking for protection from the dreaded "lawnmower blight" should involve using at least three strategically located stakes around the tree to impede the lawnmower or other vehicles of destruction. For the careful tree care provider, using a band or wood chips or other organic mulch around the tree may be sufficient to protect the tree from "lawnmower blight". For other less careful individuals, the tree may require both the mulch and tree stakes for adequate protection.
Before staking new plantings, consider the effects from staking or guying of trees compared to trees which are not staked.
- may be damaged by rubbing and girdling from stakes and ties
- the trunk will grow and bend away from the stake
- the trunk will be stressed more at the point of stake attachment and subject to increased breakage
- provide more wind resistance because the top of the tree is not allowed to move as much.
- develop weak wood from the staked position down towards the base of the tree; trunk movement is required for optimum strength of wood during development and growth.
- produce less roots.
- reduce stem taper which means less strength of the bole or trunk of the staked tree.
- height growth may be increased.
All of these effects of staking make a tree more subject to injury and less able to support itself. Staking is a very expensive cultural practice and one which requires a lot of maintenance for optimum benefit to the tree.
If possible, avoid staking and/or guying trees. Small trees, trees less than six feet tall or less than one inch in caliper or diameter, should not need staking to support them. As tree planting stock gets larger, their root system, ball-and-burlap, or pot size may not be sufficient to support them without tipping or transferring top movement down to the root system. With trees that may be able to support themselves, plant them and watch the planting hole for several days after planting. If the tree tips or leans, it needs support; if the plant stem at the soil line is moving excessively, creating a "crowbar" hole which is a quarter of an inch or larger than the stem of the tree, it probably needs support.
Anchor staking is required when the tree is unable to support itself with its existing root system. Excessive top movement breaks off the root hairs during formation, limiting the root expansion of the plant. Factors which contribute to the need for staking include size and type of tree, size of root system or root ball, wind conditions and/or site exposure, soil type, moisture conditions, and surrounding vegetation.
Anchor staking is supporting the roots or root ball until the roots of the tree grow into the surrounding soil and can then support itself. Stakes for anchoring may be wooden stakes, steel post, metal pipe, reinforcing rebars or other material to which tie materials can be fastened. Each tree requires at least three stakes, to which tie materials are fastened from the tree to the stake.
The tie material used to come in contact with the trunk of the tree should be broad and have a smooth surface to minimize the trunk abrasion and possible girdling. Some common tie material includes wide cloth belting, elastic webbing, wide rubber belts, nylon stockings, and many patented ties and support devices. Materials which may abrade and cut into the stem of tree such as wire, string, and fishing line are not appropriate tie materials.
The standard of wire inside pieces of garden hose is not as good as the wider, softer materials because it may potentially cause damage to the stem of the tree. Very large trees may not be adequately supported with fabric or belt ties; these trees may require the use of eyebolts screwed into the trees for anchoring. Use eyebolts only when the other techniques of fastening the ties is inadequate for the size of the tree. Normally, trees less than four inches in caliper can be supported without using eyebolts.
The ties should be fastened at less than one-third of the total height of the tree. Trees should not be totally restricted in movement; some movement is necessary to develop maximum wood strength. Most trees should be staked for a minimum period; for most trees, the ties may be removed after the first growing season. For large trees, two years of support may be necessary. For all trees, remove as soon as possible to minimize the adverse affects of staking.
Some trees may require support staking. Support staking is necessary for trees which are not strong enough to stand without support or trees which do return to the upright position after winds, snow or ice. The goal with support staking is to support the tree properly until it grows enough strong wood to support itself. Again, the best support system consists of at least three stakes tied with soft, wide, non-abrasive material to allow modest movement of the stem of the tree.
The attachment point should be on the trunk six inches above the point where the trunk can be held and return upright after its top is deflected. If the tree is staked too tightly so that it does not move, the risk of the tree breaking just above the staking point is increased. Strong stem formation is promoted by movement of the stem. The duration of staking depends on the tree size and how it responds; again, remove the staking as soon as the tree can support itself. Almost all trees staked beyond two years, have greater probability of breakage than trees which are staked for shorter periods of time.
One alternative to support staking for small (less than two inches caliper) deciduous trees which are so weak that standard staking may not provide sufficient support is to consider coppicing the tree. In the spring at planting time or from fall to early spring for trees previously planted, cut the tree off at a 45 degree angle and allow them to sprout. When coppicing grafted trees, coppice at least ten inches above the graft.
This technique is somewhat risky and should not be attempted with conifers or trees larger than three inches in caliper. Later, at mid to late summer, select the best sprout and remove the others. Best sprout may be defined as the straightest and the one which arises nearest the upper portion of the cut stem. The new shoot will be stronger because it has developed without support. In addition, the growth loss will be minimal because of relatively large root system feeding the new shoot growth.