If you look to the changing colors of area foliage as a sign of autumn, you may have been confused when area maples began changing colors back in July.
Fast forward to the first week of September and a significant amount of maple trees in central Minnesota are now showing off their finest fall colors. But why did it start so early, many area residents are wondering?
Area forester with the Wadena Soil and Water Conservation District Anne Oldakowski said it’s a question that she’s had come her way quite a bit throughout August.
“We’ve done a couple site visits and sent off samples to the Minnesota DNR forest health specialist,” Oldakowski said. But the results were not pointing to any smoking gun in particular.
“We looked at the trees for disease issues, but did not see that,” Oldakowski said. “Bugs didn’t appear to be the issue either.”
One conclusion that others seem to concur with is the severely cold winter that blasted the area last winter. And the color changes are not isolated to Wadena, Oldakowski found. Other parts of Wadena, Otter Tail and Todd counties have shown the same issues with young maple trees.
So why target maple trees?
Old man winter puts a hurting on maple trees more than others because of the thin bark of the maple tree, according to Val Cervenka, forest health program coordinator with the Minnesota DNR.
“Maples react to stress very easily,” Cervenka said. She said boulevard trees are even more susceptible, which is evident with the many maple trees planted near the Wadena cemetery shortly after the tornado ripped out most trees in that area. Many of those trees are showing color change and appear to have dead branches. Cervenka said maples are also prone to root girdling, when the tree roots wrap themselves around the main roots, choking the tree of moisture and nutrients. This is a common occurrence in container plants where roots are allowed to form a ball then planted without proper preparation.
Temperature extremes are also not good for the maple, especially when the trees are planted out in the open. As the sun rises and heats up the maple tree, it expands the thin bark. When the sun sets, that bark shrinks back, often causing splits in the bark, the protective skin of the tree.
The trees that have seen color changes are younger trees, with likely more shallow root systems. Root damage may be a factor in trees where just a portion of the tree, a branch here or there, has changed colors.
All is not lost … probably
If your tree was slow to leaf out this year or quick to change color, don’t assume the tree is dead, according to local tree nursery owner Mike Pete.
“After a winter like last one, I think a lot of them got shocked,” Pete said. “A lot of maples were seriously hurt.”
“Trees have this weird thing where they go into shutdown mode,” Oldakowski said. “They might lose leafs.”
“A lot of people get worried that their trees are dead,” Pete continued. “But nature has a way of taking care of itself.”
Oldakowski agrees, saying the tree is probably not dying.
“Water them well,” she said. In most cases, making sure the plant has enough moisture is a good thing for it. “Just water them like they are still alive. Baby them maybe a little bit more.”
Cervenka adds that mulching those trees out to the drip line of the branches helps protect the roots. This shades the roots and helps keep moisture where it belongs, on the roots.
Don’t be too quick to over fertilize, trim or chop the tree down. Before you make plans to remove a tree and find a replacement, experts say give it a year and see how it reacts next spring.
Pete said in some cases, the trees that do go into shutdown mode are probably the stronger tree because they’ve learned to adapt and protect themselves by conserving their energy in the face of environmental changes.
The University of Minnesota offers more tips on keeping root systems safe through the seasons with mulch.
Reducing root injury
Mulch new trees and shrubs with 6 to 8 inches of wood chips or straw.
If the fall has been dry, water heavily before the ground freezes to reduce frost penetration.
Check new plantings for cracks in the soil and fill them with soil.
Repeated freezing and thawing of soil in fall or spring causes soil to expand and contract, which can damage roots and heave shrubs and new plantings out of the ground. A 4- to 6-inch layer of mulch will prevent heaving by maintaining more constant soil temperatures.