Mike Demchik, Former Regional Extension Educator, University of Minnesota Extension Service

Deer populations have been high in Minnesota for several years. However, even at fairly low populations, deer can severely damage forestry plantations, newly planted windbreaks, and home landscaping by repeatedly browsing (eating) foliage. This damage is particularly great if preferred browse species are planted or when highnutrition nursery stock is planted near wild-grown (often lower-nutrition) species. In general, deer will damage apple, basswood, white cedar, white pine, and many tree species often included in wildlife conservation plantings. Such species often eaten by deer include highbush cranberry, mountain ash, crabapple, hazelnut, and others. Additionally, in some parts of the state deer feed upon red/Norway pine, birch, maples and even young spruce tops. Only a few trees are not sought by deer: Russian olive, some honeysuckles, lilac, Scots pine, spruce (in most of the state), and balsam fir. However, when a deer population becomes large, even these are not safe.

So how do you protect trees from deer? While there are several ways to reduce deer damage, it is almost impossible to completely eliminate it. In other states, particularly Pennsylvania and New York (but also a few places in Minnesota), electric fencing keeps deer out of high-value plantings. This fencing is expensive and difficult to maintain, but has been shown to be effective. Typically, the fence uses seven strands of wire strung to 7 feet tall. Slanting the wires outward from bottom to top (20-30 degrees), can improve its effectiveness. For small or skinny plantings (like windbreaks), woven wire fences as low as 4 feet will help, as deer will seldom jump into a small, skinny area.

Tree shelters (called tree tubes by many people) are solid or mesh plastic tubes that protect the trees. These are held in place by a bamboo stake for the mesh tubes or a wooden stake for the solid tubes. The solid tubes are usually quite expensive (usually $3 or more) while the mesh tubes are less expensive (about $1) but flimsy and likely to be damaged. While these work well and the solid tubes provide the added benefit of reducing tree death during droughts (the air inside the tube is warm and moist), they are sometimes used by deer for rubbing antlers and can be damaged by bears. This means they require regular maintenance to be effective. Additionally, the trees inside the tubes can be more easily damaged by early winter freezes and exceptionally warm early springs. Even with these caveats, tree shelters provide good protection against deer browsing.

A homemade alternative is to make individual fences 8 inches in diameter made of 4-6 foot tall turkey wire (1” X 2” holes). These work very effectively. The added benefit is that they are reusable and easy to remove (the deer will prune off any branches that grow through the wire). They cost a dollar or less each to make.

Posted in Fish and Wildlife |