“No tree becomes rooted and sturdy unless many a wind assails it. For by its very tossing it tightens its grip and plants its roots more securely; the fragile trees are those that have grown in a sunny valley.”
So said Seneca. He had good observation skills because some 2,000 years later, decades of research confirm his words.
Trees become strong with movement, much like our bones and muscles become stronger with exercise. Staking trees prevents movement and interferes with the development of a strong tree and should only be used in some situations.
When trees move in the wind or bear weight, as in holding branches, they develop reaction wood. One way to observe this wood is in the taper and caliper of the trunk. A tree with good taper in the trunk is thicker on the bottom and tapers upward. A trunk with appropriate caliper is thick enough to support its top and buffet wind stresses.
What this means is that when planting trees, they are better left unstaked, with a few exceptions. In a spot that receives high winds, trees should be staked but in a way that still allows movement. In locations that may be subject to high traffic, vandalism threats, or mechanical injury threats, trees may need heavy barriers or grill work to protect them.
As Seneca mentioned, the movement of the tree promotes root growth. A tree planted from a container has its roots in what we call a “root ball”. What we want is for the tree to develop its “root system”. Sometimes after planting a tree in an area of high wind or with heavy rains or frequent irrigations, the wind may rock the whole tree, root ball and all. If new roots have been growing out into the soil they may get broken by this action. In such a case, a clever form of staking to use is called anchor staking where short stakes are used to stabilize the root ball. One way to achieve this staking is to drive three or four wooden stakes or dowels just outside the root ball and at least one foot into the ground below the root ball. The wood can be left to decompose. There are variations of this method.
When looking for a tree to plant it would be best to select one that can stand without staking. If you have a tree that is not self-supporting, there are some guidelines for staking and tying. One to four stakes may be used. Stakes should not be against the tree, this affects the development of the xylem under the stake and actually causes the development of curvature in the trunk!
Tie material should be flat, smooth straps to minimize damage to the young bark. They should be placed about six inches above the lowest point where the tree will stand upright when the trunk is held and the top one should be at least three feet below the top growing tip. The trees should still be able to move in the wind.
So be sure to select a tree that has an appropriate trunk caliper and taper. One that has its lower branches on is best, because they create that reaction wood that makes the trunk strong. And choose one that can stand upright on its own. Take that bamboo stake off right away because it is affecting the xylem underneath it.
Try to avoid staking your tree. But if you must, allow it to still move in the wind to develop strength. Stakes should be on for only one, or maybe two, growing seasons. Please don’t forget about them. Not only are forlorn stakes and ties ugly, they can outright kill a tree!
Staking trees can do more harm than good. Staked trees may be unable to stand upright when the stake is untied. They are much more vulnerable to bark injury, or worse, from girdling of ties that are improperly applied or forgotten about. They develop smaller root systems. Their tops buffet more of the wind stresses than unstaked trees because the unstaked trees can distribute the wind stress throughout the whole tree. Staked trees do grow taller faster, but it comes at the expense of good trunk caliper and strength.
To learn more and for good visuals and details on the do’s and don’ts of tree staking there is a wealth of information online from very reputable sources.