Trees – everyone has one in their garden. And everyone has an opinion about them.
Many homeowners rely on their neighbors for “advice” regarding their trees. Often these tips are incorrect or inaccurate and are simply passed from person to person. As I’ve said many times, there are three things that will get you in trouble with your neighbor: kids, dogs, and trees. I can only help you with the latter; the other two questions will have to be resolved between you.
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That being said, I will pass on some of my tree knowledge to dispel common tree myths. The items below are just a few of the common myths; space does not allow me to address them all at this time.
My tree is green so it must be healthy.
Nothing could be further from the truth.
A tree’s vascular system provides a system for transporting nutrients and water from the soil and nutrients (sugars) from the leaves. This vascular system is known as the cambium layer which is an extremely thin layer located just inside the bark. As long as most of this layer is intact, the tree will continue to live and grow.
If the tree receives enough nutrients, water and food, it will appear green. Inside this layer of cambium is the sapwood and heartwood of the trunk. Much or most of the wood inside the trunk can decay without affecting the tree’s ability to transport food and water. However, a considerable amount of rotting wood can compromise a tree’s ability to support itself or its heavier branches.
So people are often surprised when a green tree breaks down; upon examination after failure, one can see the extensive decay in the trunk.
Outward signs of rot can include weeping, splitting of bark, bulges in the trunk, vertical cracks and carpenter ants. A certified arborist can examine your tree in more detail to determine the health of the tree and its likelihood of failure.
Mulching around a tree is always good.
Recent research has proven that any amount of mulch on the root ball of a newly planted tree is detrimental. Mulch can prevent adequate rain from reaching the roots and can retain moisture, which promotes fungal activity.
Although it is acceptable to place mulch around the root zone of an established tree, it should always be kept away from the trunk. Mulching directly against the trunk leads to excess moisture on the trunk, which promotes fungus and can lead to rot.
Also, if the mulch is used on a larger tree, it should be kept three to four inches deep. Under no circumstances should a “mulch volcano” be created at the base of the tree.
Spanish moss is killing my tree.
Spanish moss is neither Spanish nor moss. It is actually a bromeliad and is part of the pineapple family.
Spanish moss is native to South America and the southeastern United States. It is an epiphyte, which means that it uses the tree only as a support and gets its water and nutrients from the air or precipitation. It has no roots that penetrate the tree and Spanish moss does not harm the tree per se.
If Spanish moss becomes more prevalent in a tree, it is because of a thinning canopy that allows in more sunlight, creating a more conducive environment for growth. So, the thinning of the canopy is a symptom of another problem, such as a compromised root system, soil compaction, etc.
Generally, it is not recommended to remove Spanish moss from the canopy of a tree due to the cost and temporary nature of the removal. However, in the event that Spanish moss has accumulated at the end of a long limb with most of the foliage concentrated at the tip, the moss should be removed to reduce the weight on the limb in order to avoid its failure.
Before planting, prune live branches to balance the crown with the roots.
Living branches have leaves that serve as a food source for trees. Trees convert carbon dioxide and water into sugars which are used for tree growth and energy. If limbs are removed, a tree’s ability to produce food is diminished and may be insufficient to support the tree.
Always add soil amendments when planting.
If you are planting in native soil, like our deep sands, adding soil amendments is detrimental. Soil amendments are usually loamy with organic matter which is better soil than sand. Tree roots will tend to stay in the best soil rather than extending outward from the tree, which will result in a root zone with a much smaller radius and will remain encircled in the amendment.
Over time, this reduced root zone is unable to support the larger tree and the tree will remain undersized and/or topple in windy conditions.
If the soil contains old rubble, concrete or poor structure, amendments are needed. However, this situation is rare; generally, amendments should be avoided.
Humans heal, trees seal. When we are injured, we heal by growing the same tissue that was damaged. Trees do not produce the same tissue after injury.
When trees are injured, they chemically reinforce their boundaries which resist the spread of infection. They then produce coiled wood which eventually differentiates into calloused wood which produces an annual growth which gradually covers the wound. However, if the tree is older and the wound is large enough, the tree may not be able to fully seal the wound, leaving the wound exposed to insect and/or disease attack.
Secure the tree well after planting.
A slight movement of a tree after planting is necessary to strengthen the trunk. A well-planted tree cannot move and therefore will not develop the strength it needs to sustain itself. The movement of the trunk will develop a taper in the trunk so that the tree is larger in diameter on the ground than higher on the trunk.
If a tree does not have a trunk cone, it is usually due to improper staking. I usually tell people not to plant trees at all but, if you do, do it to allow the trunk to move a bit in the wind. And don’t keep stakes for more than one growing season. By this time, the tree should be established enough to support itself.
Also do not use rubber hose and wire; the rubber breaks down and the cable can damage the trunk.
Other myths abound but space does not allow me to continue.
When planting or maintaining trees, consult a certified arborist, not your neighbor.
Eric H. Hoyer is a Certified Arborist, Certified Forester, Registered Consulting Arborist and Qualified Tree Risk Assessor with Natural Resource Planning Services Inc. He can be contacted at [email protected]