Organization branches out

Tree care companies often advertise membership in the Illinois-based International Society of Arboriculture, a nonprofit educational and advocacy organization made up of 17,000 members, primarily from the United States and Canada.

In addition to promoting tree care and research, the organization runs certification programs for professionals at several levels in the business.

Certification requires passing a 200-question examination that is designed to test all aspects of the business and is good for three years, ISA Marketing Coordinator Sonia Abney says.

Periodically, members must participate in and pass continuing education programs proctored by local chapters. Continuing certification assures consumers that a member company is up to date on current techniques in the field.

The group’s Web site (www.isa-arbor.com) is primarily for members, but the general public can use it for finding the names and locations of certified arborists. A second site (www.treesaregood.com), also sponsored by ISA, is directed at consumers interested in tree-trimming basics.

Too much pruning is worse than too little, the latter site says. Getting rid of dead or diseased wood, giving clearance for utility wires, or improving shape or structure are the most common reasons to prune. “Poor pruning technique can cause long-term damage,” it warns, adding that “unlike people, tree wounds do not heal, they close. Smaller cuts close quicker.”

Flowering trees such as the crabapple, dogwood, Japanese maple and cherry may require more pruning than others since they can grow rapidly, especially when young, says Bruce Fraedrich, vice president of research at Bartlett Tree Laboratories in Charlotte, N.C.

Removal of dead, diseased and broken branches helps reduce stress on these trees and contributes to long-term health, he says. Timing depends on the kind of tree and its age. ISA also warns against topping — taking away too much off a tree’s height — since leaves provide food for a tree’s growth.

— Ann Geracimos