MYTH #1: It is necessary to "top" or "hat-rack" certain fast-growing, weak-wooded trees to prevent them from falling on your roof. Hurricane pruning is another term for this procedure in the state of Florida .
You might as well take out an axe and hack away at the trunk of the tree because you won't do much more damage. Hat-racking opens up the interior of the tree, making previously shaded portions vulnerable to sun-scalding. It takes away the tree's energy-producing canopy and causes massive re-growth at each cut. Each branch that is cut stimulates the growth of numerous vigorous shoots that will lead to branches with weak attachments. The additional weight of multiple branches can be substantial, creating a dangerous canopy for trees in a hurricane zone. Decay spreads inside the stubs and branches that were topped. Within 2-5 years after topping, the tree will have regained its height but will be more compact and hazardous then before the topping. In addition, ?topping makes the tree ugly.? In many counties the process of hat-racking is illegal and carries stiff fines.
MYTH #2: Trees should be pruned back heavily when they are planted to compensate for the loss of roots.? ?
Tree establishment is best on un-pruned trees. While it is true that pruning out branches and leaves will reduce the amount of water that evaporates from the leaves, the tree needs a full crown to produce the much-needed food and the plant hormones that promote growth. It is better to compensate for the loss of water due to evaporation by ensuring that the newly transplanted tree receives regular water to the root system.
Un-pruned trees that are properly watered will develop a stronger, more extensive root system. Limit pruning at the time of planting to structural training and the removal of damaged branches. If pruning is necessary for some reason, no more then 20%-30% of the canopy should be removed at any given time.
MYTH #3: The root system of the tree is a mirror image of the top.? ?
It is common to think that there is a taproot growing down deep into the soil with many roots shooting off of it. Taproots are actually quite uncommon in mature trees. In the species that do develop tap roots, the taproot is usually forced into a horizontal growth pattern when encountering hard sub-soils or rocks beneath the surface. The entire root system of most trees can be found within three feet of the top of the soil. However - the spread of the root system can be very extensive, often extending 2-3 times the spread of the crown of the tree.?
MYTH #4: Trees require "deep root fertilization" to get the nutrients down into the root system.
The fibrous and absorbing roots of most trees are located in the top eight inches of the soil. Roots will grow where the conditions are the best, which is where water and oxygen are available. If you place fertilizer 12"-18" deep in the soil using a deep root injector, then you will be missing the absorbing root system and placing the fertilizer too deep.
MYTH #5: When a tree loses a significant portion of its root system due to some form of disturbance such as construction, the crown should be cut back to compensate for root loss.
This common recommendation is not supported by research. Un-pruned trees seem to respond better than pruned trees following root loss. Removal of branches reduces the capacity of the tree to produce food in the leaves. The tree will likely lose some branches (if the tree survives) due to the root disturbance, and it is best to let the tree decide which ones will not make it.? Pruning should therefore be limited to hazard reduction at first. After the tree has responded to the damage, further pruning should be conducted to remove the dead branches.
MYTH #6: Pruning wounds should be painted with wound dressing.
Research has shown that the common wound dressings do not inhibit decay, do not prevent insect entry, and do not bring about faster wound closure. Many of these wound dressings will actually slow wound closure and even create a protected home for a variety of insects.
MYTH #7: When pruning a tree, the final cut should be flush with the stem to optimize healing.
Trees do not heal in the way that wounds heal on people. Trees compartmentalize wounds, generating wound-wood over the wounded area. When a branch is cut flush to the stem or trunk, the "branch collar" is removed. This creates a larger wound then if the branch was removed outside the collar. It is possible when cutting flush to remove some of the parent branch tissue as well. The spread of decay inside the tree is greater with flush cuts.
MYTH #8: Certain species of trees (such as Maple) will "bleed" if pruned early in the spring, causing health problems.
It is true that certain species will "bleed" or lose sap from pruning cuts made early in the spring. This "bleeding" does not hurt the tree. The loss of sap is inconsequential. Most routine prunings can be done at any time of the year. The worst time to prune is just after the spring flush. The best time is when the tree is dormant.
Myth #9: A newly planted tree should be staked securely to ensure the development of a stable root system and a strong trunk.
The reasons for staking a tree are to keep it upright and allow establishment. Trees that survive without staking often have more extensive root systems and better trunk taper. In Florida it is often necessary to stake the tree due to the potential of blowing over in severe weather (i.e. hurricanes). In fact, the typical landscape designs in Florida specify staking requirements. It is important that staking is done in a manner that allows a small amount of movement. This will help root and trunk development while still preventing the possibility of blowing over in a wind storm. The worst effect of staking is the possibility of damage from staking wires or ties. All staking materials should be removed after one year to avoid "girdling" of the tree.
Myth #10: Newly planted trees should have their trunks wrapped with tree wrap to prevent sunscald and insect entry.
Tree wraps have not shown to reduce extreme fluctuations in temperature on the bark. In some cases, the temperature extremes are worse. Tree wraps have proven to be quite ineffective in preventing insect entry. Some insects will burrow under the wrap and use it as an effective shield, giving the insect a nice home.
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