Take Ten: Myths of Tree Care

If you’re like most homeowners you treasure the trees on your property but know little about how to care for them. The truth is much of what you’ve heard about tree care is incorrect. Surprise surprise. Here are the top 10 myths of tree care.

Myth 1: When a tree is planted it should be securely staked to ensure the development of a stable root system and a strong trunk.

Although it is sometimes necessary to stake trees to keep them upright and allow root establishment unstaked trees tend to develop a more extensive root system and better trunk taper. Allowing a small amount of movement can actually help root and trunk development. If you must stake your tree remove the staking wires or ties after one year to avoid “girdling” the tree.

Myth 2: Newly planted trees should have their trunks wrapped with tree wrap to prevent sunscald and insect entry.

Studies have shown that the most common tree wraps do not prevent extreme fluctuations in temperature on the bark. In some cases the temperature extremes are worse. Also tree wraps have proven to be ineffective in preventing insect entry. Some insects actually like to burrow beneath it.

Myth 3: Trees should be pruned back heavily when they are planted to compensate for the loss of roots.

Tree establishment is best with unpruned trees. Although pruning the top can reduce the amount of water that evaporates from the leaves the tree needs a full crown to produce the much-needed food and plant hormones that induce root growth. Limit pruning at the time of planting to structural training and the removal of damaged branches.

Myth 4: Pruning wounds greater than 3 inches in diameter should be painted with a wound dressing.

Common wound dressings do not inhibit decay do not prevent insect entry and do not bring about faster wound closure. In fact many of the commonly used dressings slow wound closure.

Myth 5: When removing a branch from a tree the final cut should be flush with the stem to optimize healing.

Wounds on trees don’t “heal” the way that wounds on people heal. Our bodies to some extent regenerate tissues in much the same form as the tissues that were removed. Trees compartmentalize wounds generating woundwood over the damaged area. Flush cutting removes the “branch collar ” creating a larger wound than if the branch were removed outside the collar. Also it is likely that some of the parent branch tissue will be removed. In addition the spread of decay inside the tree is greater with flush cuts.

Myth 6: Certain fast-growing weak-wooded trees such as silver maple and Siberian elm should be “topped” to make them less hazardous in the landscape.

While topping these trees may reduce the potential hazard at first they will likely be more dangerous in the future. Topping stimulates growth of twigs below the cuts. Growth of many vigorous shoots leads to branches with weak attachments. Also decay spreads inside the stubs and branches that were topped. Within two to five years after topping the tree will have regained its height but will be more hazardous than before the topping.

Myth 7: If certain species of trees are pruned early in the spring they will “bleed ” stressing the tree and causing health problems.

Some trees such as maples and birches will “bleed” or lose sap from pruning cuts made early in the spring. This bleeding does not hurt the tree and the loss of sap is inconsequential. With a few exceptions most routine pruning can be done any time of year. The worst time is just as the tree has leafed out in the spring. The best time is when the tree is dormant. To maximize flowering for the following year prune just after bloom this year.

Myth 8: The root system of a tree is a mirror image of the top. Large branching taproots are very uncommon in mature trees.

If they do develop they usually will be forced into horizontal growth when they encounter hard subsoils beneath the surface. The entire root systems of most trees can be found within 3 feet of soil. The spread of the root system however can be very extensive often extending two to three times the spread of the crown.

Myth 9: Trees require “deep root fertilization” to reach their root system.

In most U.S. soils the vast majority of trees’ fibrous absorbing roots are in the top 8 inches of soil. Roots grow where conditions are best for root growth where water and oxygen are available. When we place fertilizer 12 to 18 inches into the soil we are putting it too deep.

Myth 10: When a tree has lost a significant portion of its root system such as in construction damage the crown should be cut back to compensate for root loss.

Following root loss unpruned trees seem to respond better than pruned trees. Any removal of branches will reduce the capacity of the tree to produce food in the leaves. Although the tree will probably lose some branches as a result of the root damage (if the tree survives the trauma) it is best to let the tree decide which ones. Thus pruning should be limited to hazard reduction at first. Later after the tree has responded to the damage further pruning would be in order.

Here’s something that’s not a myth: get advice from a qualifed arborist first! An arborist is a professional in the care of trees who can give you sound advice and provide the services your trees may need. Good arborists will perform only accepted practices. When choosing an arborist look for International Society of Arboriculture (ISA) certification membership in professional associations and ask for proof of insurance. Be wary of individuals who go door-to-door offering bargains for doing tree work. Don’t be afraid to check references.

Be an informed consumer. The ISA is a non-profit organization dedicated to the care and preservation of shade and ornamental trees while supporting tree care research around the world. It offers a number of brochures designed to inform consumers about trees. For a free set write to ISA at P.O. Box 3129; Champaign IL 61826.

For more information contact a local ISA-certified arborist or visit www.treesaregood.com.

Reprinted with the permission of The International Society of Arboriculture.

The Wilmington Heritage Tree Program

The recently formed Wilmington Heritage Tree Pro­gram hopes to raise public awareness of the importance of Wilmington’s historic trees. Administered under the auspices of the Wilmington Tree Commission the program is dedicated to the identification and preservation of heritage trees within the city of Wilmington. Heritage trees are those which because of their size age rarity overall beauty or historical significance represent an important aspect of the city’s history or natural landscape. Wilmington residents will be able to nominate a tree or collection of trees by completing a nomination form and submitting it to the Tree Commission. The tree(s) must be located within the Wilmington city limits and the owner’s approval is needed for Heritage Tree designation. Other criteria for Heritage Tree status as well as the nomination form are available online at: www.wilmington.gov. Go to the community link to find Wilmington Tree Commission. — Sandra Chambers