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The Landscape Alerts
Susan C. French, Extension Technician and Bonnie Lee Appleton, Extension Horticulturist, Virginia Tech
Edited from a publication found at http://tinyurl.com/6f8edx8. See the original publication for helpful photos.
What is "topping"?
Topping occurs when the vertical stem (leader) and upper primary limbs (scaffold branches) on mature trees are cut back to stubs at uniform height. Topping is also referred to as heading, stubbing, or dehorning.
1) Topping reduces food-making capacity. Trees require a large leaf surface area to provide food for maintenance and growth. Topping cuts off a major portion of the tree's food-making potential and depletes the tree's stored reserves.
2) Topping stimulates undesirable "water sprout" growth. While removing most of the buds that would form a normal branch system, topping often stimulates the regrowth of dense, unattractive, upright branches (water sprouts) just below the pruning cut. Water sprout regrowth is vigorous. A topped tree will rapidly return to its original height, but will lack its original form.
3) Topping leaves large wounds. The branch wounds left from topping are slow to close, therefore more vulnerable to insect attacks and fungal decay. An invasion by either pest can spread into the trunk, killing the tree.
4) Topping creates a hazard. Weakened stubs are more prone to wind and storm breakage because they generally begin to die back or decay.
5) Topping injures bark. Increased sun exposure on trunk and branches can lead to severe bark damage.
6) Topping disfigures trees. Ugly branch stubs, conspicuous pruning cuts, and a broom-like branch growth replace natural beauty and form. Topping reduces the real estate value of trees by 20 - 100 percent. A correctly trimmed tree increases in value at each pruning.
Some homeowners and tree pruners practice topping whenever trees reach an undesirable height. They mistakenly believe that topping will reduce the storm hazard of falling branches, when in fact, topping has the opposite effect. People also top trees when they interfere with utility wires, buildings, solar collectors, or sunny garden areas.
Selection of trees that only reach desired maximum heights eliminates severe pruning later. If you must prune a tree heavily every five to seven years, the tree is too large for the site. Replace it with a smaller species. The National Arborist Association considers topping an unacceptable practice and advises against it. Unfortunately, even some legitimate tree service companies indiscriminately top trees. Before selecting a tree service, find out which companies advocate topping and avoid patronizing them.
What are the alternatives?
In order to avoid topping, newly planted trees should be properly pruned to develop a good branch structure as they grow. When a mature tree's height must be reduced, an alternative to topping is drop-crotching.
Drop-crotching is a type of thinning cut that reduces a tree's size while preserving its natural shape. To drop-crotch, select and cut higher branches back to laterals at least one-third the diameter of the limbs being removed. Cut outside the branch collar at a 45 to 60 degree angle to the branch bark ridge. Leave the branch collar intact to help prevent decay from entering the trunk. This type of thinning cut will stimulate growth throughout the tree and discourage water sprout development.
With dr op-crotching. Lateral limbs are pruned where they join large diameter side branches. The center leader is cut back to a large diameter secondary branch so that a modified leader remains. This does not change the direction of growth. It encourages stimulation of the apical growth point.
Don't coat pruning cuts with tree paint or wound dressing, except for control of certain disease-carrying insects. These materials won't prevent decay or promote wound closure.
Can topping be corrected?
A professional arborist can improve the condition of a tree, even after it's been severely topped and shows heavy water sprout regrowth. As the water sprouts begin to gain caliper, they can be selectively "thinned out" using properly placed branch collar cuts. New growth can be directed outward to expand and round out the crown. This process will need repeating for a few years. The scars, both physical and visual, will never completely disappear.
A wiser alternative to topping is careful selection and training of your young trees. Avoid topping altogether. Allow your trees to realize their full potential for health and beauty in the landscape.Rights
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“The victim was operating a tractor and mower, aggravated a nest of bees and received more than 100 stings,” said Keith Delaplane, a University of Georgia Cooperative Extension entomologist. Africanized honeybees have been in the United States since October 1990 when they were found in Texas. In 2005, they were confirmed in Florida.
European cousin essential to crops
A sub-species of honeybee, Africanized honeybees can interbreed with the European honeybee that is well known throughout Georgia as an important pollinator and producer of honey. One-third of American diets contain food crops that rely on European honeybees for pollination, according to the Georgia DOA.
Africanized and European honeybees look and behave alike in some respects. Each bee can sting only once, and there is no difference between Africanized honeybee venom and that of a European honeybee.
However, “the African variety is extremely defensive and responds with a massive stinging reaction with little provocation,” Delaplane said.
Run, don't swat, and get inside and stay inside.
The UGA honeybee expert urges the public to become aware of how to react if Africanized honeybees attack. He offers the following lifesaving tips:
1. Be cautious around places where Africanized honey bees are likely to nest, such as abandoned sheds, bee hive equipment, discarded tires and underground cavities.
2. If you are attacked, RUN AWAY. “You may think this sounds silly, but experience has taught us that people don’t run away,” he said. “Instead, they stand and swat, which simply escalates the defensive frenzy until it reaches lethal proportions.”
3. Get inside a closed vehicle or building as fast as possible, and STAY there. “Here’s another hard lesson we’ve learned. People don’t stay inside a closed vehicle if a few bees follow them inside,” Delaplane said. “Instead, they panic and flee back outside where tens of thousands of angry bees attack them."
This pattern has repeated itself over and over in the stinging incidents entomologists have monitored in Latin America and the southwestern U.S., he said. "The lesson is, don't worry about the few bees that follow you indoors. Get inside, and stay inside."
4. European honeybees and beekeepers are our best defense against Africanized honeybees. “Some communities may be considering zoning restrictions against all forms of beekeeping. This essentially cedes territory to the enemy. Only gentle European bees can genetically dilute or out-compete the defensive Africanized variety,” he said.
First aid tips
If stung, the Georgia DOA says to follow these steps:
• Scrape – do not pull – stingers from skin as soon as possible. Pulling the stinger out will likely cause more venom to be injected into the skin.
• Wash sting area with soap and water.
• Apply ice for a few minutes to relieve pain and swelling.
• Seek medical attention if your breathing is troubled, if you’re stung numerous times or if you’re allergic to bee stings.
For more information on Africanized honeybees, read the UGA Extension publication at http://pubsadmin.caes.uga.edu/files/pdf/B%201290_2.PDF .
Additional information about animals and Africanized Honeybees (AHB) from Dr. Nancy Hinkle, UGA Veterinary Entomologist.
Note that animals in the area (essentially the neighborhood, since AHB will attack in a large area when provoked), such as horses, dogs, cats, livestock, etc. should be taken indoors and protected from bee attack while any AHB control efforts are undertaken. Some of the most heartrending tragedies have occurred when kenneled dogs were attacked by AHB after the bees were disturbed by nearby human activity.