Voles, tiny rodents often known as field mice or meadow mice, inhabit most of the United States. There are 23 species of voles living in a variety of habitats including grasslands, orchards, alpine meadows and forests. Voles are primarily vegetarian. In summer, vole tunnels can damage lawns, ground covers and tree roots. In fall and winter, voles may chew the bark of trees and woody shrubs. Left unchecked, voles can kill ornamental trees and shrubs by girdling the trunk.
Protect the trunks of trees with hardware cloth or plastic guards. The mesh or guard must extend a minimum of 4 inches into the ground. The guards should extend at least 6 inches above the snow line.
Remove food sources. In fall and winter, voles are attracted to fallen fruits from ornamental and fruit trees. Keep areas around trees fruit-free to reduce vole populations.
Cut the grass short around your trees. This will eliminate a food source (grass) and reduce breeding and hiding places.
Pull mulch back at least 3 feet from the base of trees to protect bark from rodent damage.
Spray bark with a nontoxic repellent and sprinkle repellent powder or crystals around the perimeter of trees and shrubs. Repellent powders and crystals mimic the scent of predators and voles will keep a safe distance away.
Attract predators. Voles are a favorite prey of owls, cats and other predators. Remove any hiding places to assist the predators in controlling vole populations.
Use toxicants as a last resort. Zinc phosphide baits are the most common vole pesticide, but they are hazardous to ground-feeding birds. They should always be placed in vole tunnels or bait stations to protect nontarget species.