National Standard says: ‘Don’t Top Trees’
For years, tree topping was considered the easiest and cheapest way to make mature trees safer and reduce their size. Today, tree researchers have proven that both of these assumptions are false. “Millions of trees have been hacked with little or no consideration to their health and structural integrity,” says Tchukki Andersen, BCMA and staff arborist with the Tree Care Industry Association. According to TCIA, many of these trees eventually die as a result of the damage. Others eventually become unsafe, leading to dangerous limb breakage or whole tree failure years after the topping was done. The Tree Care Industry Association and the American National Standards Institute A300 pruning standards consider topping to be an unacceptable pruning practice. “Tree service companies that follow industry standards will refuse to top your tree,” notes Andersen.
What is topping?
Topping is a non-standard pruning procedure where larger trees are severely cut back to a pre-determined size. It is also known as hat-racking or de-horning. Topping was a traditional pruning method that was considered acceptable long ago. The following is up-to-date information about topping:
• leaves large exposed wounds, which can pre-dispose the tree to infestation or other future health problems;
• ruins tree structure;
• removes too much foliage, disrupting the tree’s energy storage;
• stimulates vigorous new growth, which is prone to breakage;
• increases tree maintenance costs; and,
• destroys the tree’s appearance and value.
Why trees are topped?
Some consumers top trees out of tradition, since that is the way it was done in the past. Other consumers mistakenly believe that topping a tree reduces its size and lowers the maintenance cost. However, published research has proven that many species of tree that are topped actually grow more over a five-year period when compared to trees that were pruned correctly. As a result, there is no savings for the consumer. Andersen adds, “Topping a tree often results in greater expense for the consumer over the long run; for this reason, tree care professionals consider topping a form of consumer fraud.”
What actually happens when trees are topped?
Trees try to maintain a delicate foliage-to-root ratio and have to guard against wood-eating insects and decay organisms that can quickly destroy a tree once they get a foothold. Topping removes too much of the foliage, upsetting this ratio. This limits the tree’s ability to sustain its own roots. The large cuts on the limbs are made at locations where the tree has no natural defense against pests. This makes them more susceptible to insects, disease and decay. Limbs weakened by decay can’t handle the weight of rapid regrowth. In a few years, if the tree survives, it may become a bigger safety hazard than it was prior to topping. The regrown branches break and fall. The tree itself may fall due to root dieback. Conifers, if they don’t die immediately and do regrow, will never look the same.
What is the alternative?
Tree care companies and tree services have the ability to make your tree look more attractive, safer and, yes, even somewhat smaller using appropriate corrective pruning in accordance with ANSI A300 standards.
What can you do?
Ask your tree service to state on a written proposal: “All work done according to ANSI A300 standards.” Ask that pruning specifications, written according to ANSI A300 standards, be provided on the proposal. Specifications are details that tell you exactly what work the tree company plans to do so that there are no misunderstandings.
Utility line clearance
The ANSI A300 pruning standard has a section on utility line clearance tree trimming. Utilities that trim trees according to ANSI standards will not top your tree. If this is a concern, you should contact your utility forester to learn more.
Find a professional
Homeowners who would like a professional arborist to assess their trees should contact the Tree Care Industry Association (TCIA), a public and professional resource on trees and arboriculture since 1938. It has more than 2,000 member companies who recognize stringent safety and performance standards and who are required to carry liability insurance. Oregon Tree Care is a proud member of the TCIA.