Deer damage to trees: browse and antler rub, as extension services describe it

This page reports what the official source says. It is not legal advice: ask the office named here. The University of California note below says that in California deer are game animals and that the Department of Fish and Wildlife has authority to issue a depredation permit for lethal removal when verifiable damage is occurring. The page describes what the sources say the damage looks like and the guards they list. It does not say what to do about any tree or any animal. For protected species and nests in tree work, see the guide on wildlife and the law.

Browse: torn, ragged edges

The University of Kentucky Extension workbook on animal pests in Christmas tree plantations says deer damage is distinctive because deer lack upper incisors, so they cannot make the sharp, oblique cuts of rabbits or voles. Browsing leaves a jagged or torn surface on terminal twigs, stems and buds, and the height of the damage often rules out other mammals. The University of California IPM Pest Note on deer (revised November 2019) agrees: deer browsing leaves ragged edges on leaves and tender stems. It adds that in areas of native oak a browse line is often visible, with all green leaves and small new stems eaten as high as deer can reach, usually to a height of 4 to 5 feet.

South Dakota's forest health update of February 5, 2020 says deer often group together in winter and browse heavily where they are confined, and that deer tear or break shoots, which separates their work from rabbit damage. It lists arborvitae, dogwood and maple as favorites, with soft-needled pines browsed when food is limited. Iowa State University Extension says arborvitae and yews are the most susceptible to winter browsing, and that damage is often from about 6 feet down.

Antler rub: stripped bark

Iowa State says that in fall bucks rub antlers on trees to remove dried velvet and to mark territory. The rubbing removes the thin bark of small trees, which disrupts the water and nutrient tissues, and the trees it names as most often hit are young ones with pliable trunks and thin, smooth bark. It says the chance of damage falls a good deal once a trunk is corky and thick-barked and 3 to 4 inches across or more, and that trunk damage typically sits 1.5 to 3.5 feet above the ground. Purdue University and the USDA Forest Service (publication FNR-216, hardwood plantations) say trees 5 to 10 feet tall are favoured, that rubbing runs from September through November, and that damage shows as long strips of torn or shredded bark that can girdle the tree. Kentucky says trees are often under 5 years old, and can have branches torn off. The California note says rubbing is not a problem for larger trees, while saplings and small limbs can be badly damaged or destroyed.

Whether the sources call it harmful

Source	What it says about the effect
Purdue and USDA Forest Service	Hardwoods are not typically killed by browse but can be stunted and grow multiple leaders. Browse can kill conifers. Rub wounds give openings to wood-rotting organisms and may leave permanent butt log defects.
Iowa State	If rubbing removes bark around the trunk the tree is girdled, and growth above the girdle eventually dies. Lightly browsed secondary branches recover, and many deciduous shrubs resprout.
Kentucky	Complete girdling of trunk or roots can kill a tree, and heavy browsing at terminal buds can disfigure its shape.
California IPM	Browsing can stunt newly planted fruit and nut trees, sometimes delaying fruit for several years.

Guards the sources list

Iowa State describes tubes, wraps, wire cylinders and sets of stakes around individual young trees, and fencing as the most effective but often most costly way to keep deer out. Purdue and the Forest Service describe tree shelters, electric fences, barrier fences of plastic mesh or wire, and individual cages, and say tree guards of the kind used against gnawing will not limit deer damage. California IPM calls properly built and maintained fencing the most effective method and also covers deer-resistant planting, noting that lists of resistant plants only show which are less preferred, since deer eat them when food is scarce. The sources give heights and spacings that differ by setting, so the figures are best read in each publication. Iowa State also says no applications are known that mitigate deer damage once a tree is badly damaged, and that wound dressings, paints and wrappings do not help.

Next to rubbed trunks, a look-alike is rabbit gnawing, which the page on rabbit damage covers, and vole gnawing near the soil line is on the vole damage page. The group is listed on the wildlife damage to trees page.