Trees – everyone has one in his or her yard. And everyone has an opinion about them.
Many homeowners rely on their neighbors for “advice” regarding their trees. Often, this advice is incorrect or inaccurate and is simply passed on from person to person. As I have 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 issues will have to be resolved among yourselves.
That being said, I will impart some of my tree knowledge to dispel common myths concerning trees. The items below are only a few of the common myths; space does not permit me to address all of them 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 to transport nutrients and water from the soil and food (sugars) from the leaves. This vascular system is known as the cambium layer which is an extremely thin layer found just inside the bark. As long as most of this layer is intact, the tree will continue to live and grow.
If the tree is getting sufficient nutrients, water, and food, it will appear green. Inside this cambium layer is the sapwood and heartwood of the trunk. Much or most of the wood within the trunk can be decayed without affecting the tree’s ability to transport food and water. However, a considerable amount of decayed wood can compromise a tree’s ability to support itself or its heavier branches.
Thus, people are often surprised when a green tree fails; upon examination after failure, one can see the extensive decay within the trunk.
Outward signs of decay can include oozing, bark splitting, bulges in the trunk, vertical cracks, and carpenter ants. A certified arborist can examine your tree in greater 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 over the root ball of a newly planted tree is detrimental. The mulch can prevent adequate rainfall from reaching the roots and can hold in moisture which promotes fungal activity.
While it is OK to place mulch around the root zone of an established tree, it should always be kept away from the trunk. Mulch directly against the trunk leads to excessive moisture on the trunk which promotes fungi and can lead to decay.
In addition, if mulch is used on a larger tree, it should be kept to a three- to four-inch depth. 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 in the pineapple family.
Spanish moss is native to South America and the southeastern United States. It is an epiphyte which means it uses the tree only for support and gets its water and nutrients from the air or rainfall. It does not have roots which penetrate the tree and Spanish moss does not harm the tree, per se.
If Spanish moss becomes more prevalent in a tree, it is due to a thinning canopy which allows more sunlight, creating a more suitable environment for growth. Thus, the thinning canopy is a symptom of some other problem, such as a compromised root system, soil compaction, etc.
Generally, it is not recommended that Spanish moss be removed from the canopy of a tree due to the expense and temporary nature of the removal. However, in the event that Spanish moss has accumulated at the end of a long limb which has most of the foliage concentrated at the end, the moss should be removed to lessen the weight on the limb to prevent limb failure.
Before planting, prune living branches to balance the crown with the roots.
Living branches have leaves which serve as the food source for trees. Trees convert carbon dioxide and water into sugars which are used for growth and energy for the tree. If limbs are removed, the ability of a tree to make food is diminished and may be insufficient to support the tree.
Always add soil amendments when planting.
If planting in native soil, such as our deep sands, adding soil amendments is detrimental. Soil amendments are generally loamy with organic matter which is better soil than the sand. The tree roots will tend to remain in the better soil rather than expand outward from the tree, resulting in a root zone with a much smaller radius and remain encircled within the amendment.
Over time, this diminished root zone is incapable of supporting the larger tree and the tree will remain undersized and/or will topple over in a wind event.
If the soil contains old building rubble, concrete, or has poor structure, then amendments are necessary. However, this situation is rare; generally, amendments should be avoided.
Trees heal wounds.
Humans heal, trees seal. When we are injured, we heal by growing the same tissue as was damaged. Trees do not produce the same tissue after wounding.
When trees are wounded, they chemically strengthen their boundaries that resist the spread of infections. They then produce wound wood which eventually differentiates to callous wood which produces annual growth which gradually covers the wound. However, if the tree is older and the wound large enough, the tree may not be able to totally seal over the wound, leaving the wound exposed to insect and/or disease attack.
Brace the tree tightly after planting.
Slight movement of a tree after planting is necessary to strengthen the trunk. A tightly staked tree cannot move and thus will not build the strength it needs to support itself. Movement of the trunk will develop a trunk taper so that the tree is larger in diameter at the ground than further up the trunk.
If a tree has no trunk taper, it is usually due to incorrect staking. I generally tell people not to stake trees at all but, if you do, do it to allow the trunk to move somewhat in the wind. And, don’t keep the stakes on for more than one growing season. By that time, the tree should be established enough to support itself.
Also, do not use rubber hose and wire; the rubber will break down and the wire can damage the trunk.
Other myths abound but space does not permit me to continue.
When planting or caring for trees, consult a certified arborist, not your neighbor.
Eric H. Hoyer is a certified arborist, a certified forester, a registered consulting arborist and a qualified tree risk assessor with Natural Resource Planning Services Inc. He can be contacted at email@example.com.