Superior celebrates trees by learning how to prune
Seminar shows the proper way to care for trees with pruning to grow a healthy urban forest.
SUPERIOR — The city took a different approach to honoring Arbor Day this year.
Instead of planting a tree or ceremony in honor of the city’s urban forest, the Urban Forestry Tree Board offered a seminar Thursday, April 27, to learn the proper way to care for the city’s young trees.
After all, the city’s boulevards are lined with young trees after the city discovered emerald ash borer in and removed thousands of ash trees as a result. Thousands of young trees have been planted to replace them.
Nathan Schuettpelz and Ryan Rodefer of Wachtel Tree Science Inc. provided the tools and techniques to properly prune young trees.
About a dozen city workers were joined by city workers in Ashland and a master gardener took advantage of the hands-on training course to learn the proper way to prune trees.
“Pruning is wounding,” said Schuettpelz, who led the classroom portion of the lesson. “However, when it’s done appropriately and reasonably, we’re doing it for the greater good. And if we make good cuts, the tree can appropriately seal off that decay and outgrow it.”
He said the primary reason for pruning trees is safety.
“We do that by pruning trees to avoid poor structure,” Schuettpelz said. “Trees aren’t engineered. They’re living organisms. They’re not perfect. We’re not perfect. And trees can fail.”
He said the goal of Thursday’s lesson is to enjoy the benefit of trees safely.
When it comes to pruning trees, Schuettpelz said the goal should be to promote branch unions that have as wide as a gap as possible, 45 degrees or greater to the main stem to allow branch diameter to increase and provide plenty of space to allow locking tissue between the branch and stem to grow.
Branch unions that are too close together develop with less interlocking tissue and can hold moisture that results in decay, which is more likely to fail in severe weather events, he said. Known as codominant stems, the branches develop with roughly the same diameter and grow from the same origin point.
Proper pruning should retain a balance between the exterior crown and interior crown of the tree so photosynthesis can take place, Schuettpelz said.
Photosynthesis is the process by which trees use energy from the sun and carbon dioxide from the air to make the food they need to live and grow, which contributes to the production of oxygen.
With trees that spread, like elm, honey locust, Kentucky coffee trees, some species of hackberry and silver maple, he said the goal should be balance and limbs that originate in the lower canopy should stay in the lower canopy.
“We can promote better spacing of branches through the crown, reduce some of these codominant stems to reduce the loading that is exerted at the union where they meet the trunk,” Schuettpelz said.
Oaks and elm shouldn’t be pruned in the summer to prevent the spread of disease, Schuettpelz said. He said when there is storm damage that must be cleaned up, tree paint is necessary to seal the wounds to prevent beetles from spreading disease. However, he said, tree paint isn’t required in most other cases because trees do a good job of sealing up the wound.
“We don’t want to prune past the branch collar,” a swelling of tissue where the branch meets the stem, Schuettpelz said. He said to plan where the final cut is going to be, go out 6-12 inches to make a first, partial cut through the branch, a second cut a little further out to remove the branch and make the final cut near the branch collar at a 45-degree angle.
As a rule of thumb, he said branches cut should be no larger than one-third of the diameter of the tree.
Rodefer said safety glasses and a hard hat are musts when pruning trees. Tools he recommends are gloves to prevent injury, bypass pruners and loppers, sharp saws and interlocking poles.
Schuettpelz said the least aggressive tool for the job is best to avoid tearing.
After the classroom lessons, participants took to the field to put what they learned to work.
Councilor Ruth Ludwig, a master gardener, said she’s done tree pruning primarily with fruit trees in her yard and the community garden.
“I had taken some pruning classes through UW-Extension with the master gardeners and this to me was a lot more detailed than what I’ve been through,” Ludwig said. “I learned a lot more in-depth, and I think it makes me more confident to do pruning.”