For mature tree, best to hire a pro to inspect, prune it
Midwinter is far from T-shirt weather, but it’s still prime time for one kind of yard work: pruning trees.
Winter pruning while trees are dormant has a number of advantages, according to Sharon Yiesla, plant knowledge specialist at the Morton Arboretum in Lisle.
“With the leaves gone, it’s easy to see the structure of a deciduous tree,” she said. “Insects and diseases are dead or inactive in the cold, so they are much less likely to enter the wood through pruning wounds.” Oaks, for example, should only be pruned in winter to avoid spreading the deadly disease oak wilt.
Frozen soil means crews are less likely to trample your other garden plants as they work around a tree. And since you will likely need to hire a professional to inspect and prune your tree, you can stay indoors in your T-shirt.
“We don’t recommend that homeowners try to prune mature trees,” Yiesla said. “It’s too dangerous for the homeowner and the tree.” Unless you can reach branches to prune them with your feet on the ground, she said, hire a professional.
Make sure the person you hire is a trained, certified professional arborist. “Certified arborists have the training to see things that a homeowner probably wouldn’t notice, such as early symptoms of disease,” said Jake Miesbauer, an arboriculture scientist at the arboretum who studies the structure and growth of trees and how to improve pruning techniques.
Arborists know the growth characteristics of different tree species, which problems each species may be prone to and how each type needs to be pruned, he said. They also have the skills and equipment to work safely high above the ground and to maneuver the dangerous weight and bulk of pruned branches.
To find a certified arborist, see the website of the International Society of Arboriculture at isa -arbor.com/For-the-Public or the website of the Illinois Arborist Association at illinoisarborist.org.
“Hiring a certified arborist does cost money,” Yiesla said, “but it’s an investment in your own safety, your trees’ health and the value of your property.”
A professional inspection may reveal that your tree doesn’t need much work. “Mature trees need very little pruning,” Miesbauer said. In fact, it’s best to avoid cutting off large branches unless they are dead, damaged or pose an acute risk. The loss of a major branch can unbalance a big tree and make it less stable.
Miesbauer recommends having trees professionally inspected and pruned every three to five years for their first 30 years. Mature trees still should be inspected periodically by a professional as a preventive measure.
“By the time a homeowner notices a crack or a disease symptom, it’s probably well advanced,” Miesbauer said.
If the tree gets regular inspections, a trained arborist will have a chance to spot the issue and handle it before it becomes a larger and more expensive problem.
For tree and plant advice, contact the Arboretum's Plant Clinic (630-719-2424 or plantclinic@mortonarb.org).