Protecting young trees from voles, rabbits, deer and squirrels

A newly planted tree sits at the center of a small food web, and most of the web wants a bite. The young trees we see lost to animals are rarely eaten in a night. They are girdled under the snow in February, clipped off at the ankle in a hard winter or rubbed raw by a buck in October, and the damage is found in spring when the tree fails to leaf out. Each animal leaves its own signature, and once you can read it the protection is straightforward.

Voles and mice: girdling at the base

Meadow voles and pine voles are the quiet killers. They work under snow, deep mulch and tall grass, gnawing bark at the soil line and just below it, where nobody looks. The marks are small, irregular tooth scrapes, roughly an eighth of an inch wide, at odd angles, sometimes stripping the bark all the way around; pine voles chew roots as well. A girdled tree often leafs out in spring on stored reserves and collapses in early summer, so the cause is often missed. Mice do the same on a smaller scale.

A mulch volcano against the trunk, one of the planting mistakes we see most, is a vole shelter with food inside. Pull mulch back six inches or more, mow grass short around young trees through fall, and guard the base with hardware cloth, as described below.

Rabbits: clean cuts at 45 degrees

Cottontails clip small stems cleanly at about 45 degrees, and in winter gnaw bark from the lower trunk with paired tooth marks wider than a vole’s. Their reach is about two feet from the ground or the top of the snow, so in a deep-snow winter the damage sits higher than you expect. Slant-cut twigs and round droppings nearby are the giveaway. A guard taller than the snow depth plus two feet stops them.

Deer: torn tips and shredded bark

Deer have no upper front teeth, so a browsed twig ends in a ragged tear rather than a clean cut. They browse buds and shoots to about five feet, and a young tree within reach can be held at hedge height for years. In fall, bucks rake their antlers on trunks one to four inches thick, shredding the bark in vertical strips and often snapping the stem. Rubbing is the worse of the two: a buck can girdle a ten-foot tree in an evening, and he comes back to the same one.

Squirrels: stripped branches and clipped twigs

Gray squirrels strip bark from the upper branches of maples, beeches, sweetgums and sycamores in late winter and spring, for the sweet inner bark and for nest lining, leaving patches of bare wood high in the crown. In late summer and fall they bite off twig tips, littering the lawn under an oak, and they dig up newly sown seed. Squirrels rarely kill an established tree, though stripping can kill a branch, and there is no practical way to protect a crown. Where they matter is a seedbed, which needs a hardware-cloth lid until the seedlings are up.

The protection that works

• Hardware-cloth cylinders. Quarter-inch mesh stops voles and mice; half-inch stops rabbits but lets voles through. Make a cylinder 18 to 24 inches tall, taller where snow gets deep, and a few inches wider than the trunk. Sink the bottom edge an inch or two into the soil so nothing tunnels under, and pin it with two or three landscape pins, the U-shaped steel staples sold for landscape fabric, so it cannot be pushed over. Keep mulch pulled back so the flare and the base of the cylinder sit in open air. This one measure prevents most of the losses we see.
• Tree tubes. Plastic or paper tree shelters keep rabbits and deer off a seedling, and a tubed seedling usually gains height faster at first. The downsides are real: tubes overheat in a hot summer, the sheltered stem grows tall, thin and unable to stand on its own when the tube comes off, wasps and mice nest inside, and a tube never removed girdles the trunk. If you use them, stake them well, keep them ventilated, and remove them in stages once the tree has grown out the top.
• Welded-wire cages for deer. A cylinder of welded wire with two-by-four-inch openings, about five feet tall and four to five feet across, held by two or three stakes, keeps deer off the tree and bucks off the bark. Deer cannot reach the middle of a wide cage; a narrow one just guides their mouths to the outer leaves. Pin the bottom with landscape pins and, where rabbits are a problem, line the bottom two feet with hardware cloth.
• Fencing. Where deer pressure is heavy and you are planting more than a handful of trees, an eight-foot fence around the planting beats a cage on every tree.
• Repellents. Sprays based on rotten egg, hot pepper or predator scent reduce browsing for a few weeks, then wash off or get ignored. Use them as a bridge through a bad stretch, not as the plan.

Taking the protection off

Every guard is temporary, and every one becomes a hazard if forgotten. Loosen or replace a hardware-cloth cylinder as the trunk grows, and remove it once the bark has thickened and roughened, usually after four to six years. Take down a deer cage once the leader and lowest branches are above the browse line and the trunk is too thick to snap in a rub. Check every guard each fall: ties cutting into bark, tubes packed with mouse nests, mulch crept back to the trunk. All are fixable in ten minutes and fatal in ten months.

Rows of small holes on the trunk are not an animal problem but a bird’s, and need none of this.