The seven deadly sins of urban tree care

A common thread linking the seven deadly sins is that each one is committed with the very best of intentions. Everyone who plants a tree anticipates that the tree will live a long and fruitful existence and be enjoyed and appreciated for many generations to come.

Improper staking, the fifth deadly sin, conforms to this pattern of good intentions. Newly planted trees need to be properly and firmly staked so that they will grow up straight and strong, ... right? Not necessarily.

Newly planted trees may or may not require support, and when they do, staking should be done with care and an understanding of how trees develop and what unnatural practices would cause a young tree to require artificial support in the first place.

Mother Nature never artificially supports a young tree. That’s because every tree is provided with a natural support system developed and guided by its genetic code. Beginning with the emergence of cotyledons (seed leaves) and continuing throughout its life, every tree engineers its growth in response to the environmental stimuli that affect it.

Just as humans must exercise to develop a healthy muscle structure, trees develop reaction wood through exposure to the forces generated by gravity, wind and the quest for sunshine. Bottom line is, left to their own devices, trees do just fine without our assistance and interference.

Unfortunately, like so many corseted young maidens, trees are often strapped up tightly to nursery stakes. Sometimes this is done to facilitate a hyper-straight trunk, as if they were destined to be soldiers!

More often, a nursery stake is a band-aid used to disguise and support a weak, skinny trunk caused by the premature and unrelenting removal of juvenile branches (more on this in Part 6). Whatever the reasoning, a tree that has been grown with a nursery stake will usually require a weaning period with support stakes before it will be able to stand up on its own trunk.

It is important to remove nursery stakes and any ties at the time of planting. Supporting a developing trunk with a nursery stake is like leaving a cast on a leg that isn’t broken. Muscles atrophy when they aren’t being used and tree trunks won’t develop reaction wood if they can’t dance around and experience the forces of nature.

If the tree is unable to stand on its own once the nursery stake is removed, then it will require support while it builds up strength. The best way to provide support is with two sturdy stakes, driven into the ground on opposite sides and just outside of the root ball.

The stakes should be oriented perpendicular to the prevailing wind and angled slightly away from the crown to prevent the branches from making contact as they blow around. Tie the tree to the stakes at the lowest, single point that provides the necessary support to hold the tree upright.

The material that contacts the tree should be something soft and non-injurious to the tree. Commercial products such as ArborTie and TreeTie are available, but wide strips torn from an old T-shirt or an old tube sock work just as well in my backyard.

Tie opposing loops one on top of the other and avoid interlocking the ties that come from opposite sides since they can pinch the trunk as they are pulled apart. Wire covered with rubber hose should never be used to support a tree since it will bruise the young cambium and cause permanent scarring.

Although many architectural plans specify tying the tree at two points, and many landscape companies insist on following the practice, it is best to tie the tree at one point only. As the wind blows against the top of the tree, the bottom must be able to flex in response. Tying at two points restricts the bottom of the trunk and may cause the tree to snap off at the upper tie point.

Many desert trees don’t require staking at all since it is quite natural for them to grow perpendicular to the ground when young. As the trunk develops strength, a new leader arising from the bend will assume dominance and grow upward. The original leader that is growing sideways will become subordinate and eventually inconsequential in the overall structure of the tree.

Conversely, when large trees are transplanted, it is a good idea to provide some support even if the tree is standing fine on its own. In this case, the tree should be anchored or guyed to stakes from a few feet above grade to provide support and prevent the tree from blowing over while new roots are establishing.

Even properly staked trees are at risk of neglect. Once the support system is installed, it is critical to perform regular inspections to insure that no damage is occurring to the cambium and that the tree is not growing into the ties. A tie that is restrictive will obstruct the flow of carbohydrates in the phloem, causing the stem to swell above the obstruction.

Eventually, circulation of carbohydrates may be completely cut off, preventing the root zone from receiving vital nutrition from the canopy. Furthermore, when a stem grows around a wire or other tie, it causes a permanent wound. This type of wounding is similar to scoring a piece of glass and creates the potential for the trunk to snap off at some point in the future.

Support staking is a temporary treatment and stakes should be removed as soon as possible, usually between six and 12 months. Trees that are unable to support themselves after 12 months are most likely girdled and should be replaced. Trees that continually blow over in windstorms should be removed as soon as possible as they tend to become more hazardous as they grow larger.

Similar to raising young children, the goal of staking is to encourage independence and self-reliance by providing gentle support and guidance where needed. Of course you hope that the tree will stay around a whole lot longer!

Visit www.treesaregood.com for additional information on staking a tree and other important topics.
Tina McKeand can be reached at TMcKeand@davey.com.