To catch a better glimpse of the snowfall most of the Midwest has yet to receive, I recently made a visit to New Jersey, which was struck by a memorable Snowtober this fall. I walked among the trees nearby, marveling at the beautiful, fluffy, white snow on their branches and enjoying the calming atmosphere. All was quiet, peaceful.
One line from The Night Before Christmas comes to mind: "Not a creature was stirring, not even a mouse."
But then I contemplated the authenticity of that familiar phrase. Despite the serene appearance of winter landscapes, does snow protect trees and shrubs from winter scavengers? Voles and deer, for example, are quiet creatures that can cause severe damage to your trees. In fact, critters could be tunneling just below the soil surface, under sheets of white snow, wreaking havoc without your knowledge.
Anand Persad, regional technical advisor and entomologist for The Davey Institute, says the No. 1 winter tree scavenger is the vole. Tree owners, however, very frequently misdiagnose vole damage, blaming it on winter injury, rabbits, vandalism or other causes. "Only one in about 50 cases of vole damage is diagnosed properly," Persad says.
Voles, or meadow mice, resemble moles or shrews but have smaller feet. Although their deceiving size misguides our understanding of the extent of damage they can do, voles can permanently inhibit your trees' ability to survive. They create 1- to 2-inch surface runways under the snow, gnawing on the bark of small trees and feeding on grasses and other herbaceous plants. "Voles can cause heavy and sudden damage to forests, orchards and ornamental tree stands, especially under heavy snow cover," Persad explains.
While other critters hibernate during the winter months, voles stay active. However, the food sources they need to keep going-and keep digging-might run low. "If food is scarce, root flares and the bark of mature trees may be attacked," Persad says. "Feeding activity in this case is unexpected and most often detected after snow melt."
Vole behavior causes tree damage ranging from irregular gnaw marks and other unusual markings on tree bark to girdling around the base of the tree. While rabbits, for example, leave islands of bark behind after gnawing at the tree, voles do not.
Unfortunately, if the damage is severe, there is nothing to do to save the tree. However, to prevent voles from attacking your trees, border the bases of susceptible trees with wire mesh 3 to 6 inches below the soil line to a minimum of 18 inches above the surface.
"Remove ground cover of nearby weeds, flowers and low-growing shrubs," Persad says, "and maintain mulch at a 2-inch depth to keep vole populations low." If your area suffers heavy snow cover, Persad suggests clearing away the snow around your trees with known vole habitats.
In addition to voles, other winter tree scavengers, such as deer, can cause minor to severe damage to trees.
Deer will eat anything they can find in your lawn, so it's important to "eliminate the food source," Persad says. "Feeding deer makes them tamer."
If deer simply browse the tree, little damage will occur and the leaves generally grow back. However, when deer rub their antlers on tree bark, the resulting damage is usually a permanent wound. Deer also feed on young trees and leave droppings in yards.
Bark wounds may scab over, but to prevent further deer damage on your trees, use hardwire mesh or deer repellant to prevent them from approaching your landscape trees.
To fully enjoy this season's peaceful, white winter scenery and worry less about your trees and what lurks beneath the snow piles surrounding them, practice early prevention techniques to keep scavengers away. Then, come spring, you'll be pleased to see few surprises under the melted blankets of snow.