Minnesota’s Drought Puts Trees Under Stress, Could Cause Fall Colors to Show Early

(KNSI) – When asked how much stress Minnesota’s worst drought since 1988 is putting on the state’s trees, Katie Drewitz says “the short answer is: a lot.”

Drewitz is the University of Minnesota local extension educator for horticulture, small farms and local foods for Stearns, Benton and Morrison counties. With half the state — including the entire St. Cloud area — experiencing extreme or exceptional drought conditions, from fish to crops, living things are taking a beating this summer. Trees are no exception, even mature trees that don’t usually need as much watering as saplings do.

“Most of the tree’s roots are in the first zero to 18 inches of our soil, which I think we sometimes forget about, thinking that they’re such large trees, their root systems go super deep,” Drewitz said. “But that is not always the case, and because of that, in this extreme drought that we’ve had, the soil in some places is dry very far down. So, those trees are getting virtually no water.”

When trees get stressed out by drought, disease, insect infestations, being planted incorrectly or any combination of issues, Drewitz says deciduous trees may lose their leaves earlier than expected.

“Most of our lawns went format very early on this summer, and that was self-preservation to be able to survive,” Drewitz said. “The trees are sort of doing the same type of thing where they are doing everything they can to conserve energy, and keeping their leaves green and beautiful takes a lot of energy.”

While the drought could prompt trees’ fall colors to appear earlier this fall than normal, Drewitz says that timing depends on a lot of factors. And, sometimes the stress a tree undergoes won’t physically show up for a while.

“If your trees are still looking super great and healthy, that’s fantastic and definitely what we want to be seeing, but we could see effects of this drought long-term,” she said.

A dry winter could compound on those long-term issues. If the state receives enough snow this winter, Drewitz says the moisture, insulation and ground cover will help hydrate trees and other plants and keep the frost shallow.

“If we have very little snow cover and a very cold winter, that frost is going to go significantly deeper, which could impact our root systems on all of our plants,” Drewitz said.

For now, Drewitz says if you have trees in your yard, choose to water established, important trees.

“If you have 10 trees in your yard, pick the two, maybe three that you really want to focus your watering efforts on,” she said. “Lawns are a lot easier to replace than trees.”

Drewitz says Morrison, Benton and Stearns county residents can reach her at 320-355-6169, extension 1 for tree and lawn maintenance information. People in Sherburne, Wright or other counties around the state can contact their local extension office.

___