March 2, 2013

1 - Various animals may damage tree bark in the winter, but there are some treatments that may protect the tree.

Yard and Garden March 2, 2013


I have young apple, apricot and cherry trees that were planted a couple of years ago. They are near a creek with abundant wildlife. The trees are about ¾ to 1 inch in diameter and about 3-5 feet tall. Some critter is slightly chewing on the stem - not very deeply, superficially. It may be deer but there is a woven fence around them. It could be rats, or porcupines. The damage is too tall for rabbits. The bottom of the tree is wrapped with paper sacks. Is there any type of wrapping that she can use on the whole tree to prevent the chewing if it worsens? Harding County


It would help if the animal doing the damage could be identified. Perhaps loose soil or wet soil at the base of the trees will make an impression of the animal's footprint to narrow down the choices. Another option may be to spread flour or even dry plaster around the base of the tree to help get a footprint that can be photographed (need a windless night). Or, perhaps the producer can find prints in snow and take a picture.

In the absence of a better identification, let us consider the chewing damage. Are the teeth impressions distinct? What size are the teeth? As far as the potential damage caused by the chewing, it is not the depth that matters. More important is whether or not the twig is girdled or significantly encircled by the damage. If the bark or epidermal layer is stripped down to the cambium and slightly below, the critical layers of the branch have been damaged. How much the twig or branch is impacted depends on the width of the damage. If the twig is completely encircled and pruning is an option, the twig should be removed at a bud or branch below the damage. If the damage is on a branch or the trunk low enough, a bridge graft may be needed to carry water and nutrients across the damaged area. From your description, this is probably not necessary.

Materials you can use to protect the bark include the chicken wire loosely wrapped around the trunk and lower branches (removed in the spring after growth begins). If the animal is a mouse, rat, porcupine or other animal that can chew in the open spaces in the chicken wire, you may have success with a loose wrapping of heavy aluminum foil, the brown paper sacks, or even heavy butcher paper. A commercial product made from a mixture of bees wax and petroleum jelly makes a sticky barrier that may discourage pests climbing the trunk, but it can cause problems if it gets onto the feathers of birds.

Larger animals can often be kept away by a fence about 3 - 5 feet out from the trunk supported by tall metal posts. This should keep the animals far enough away that they cannot reach the trunk and branches. Smaller animals will not be deterred by such a fence. You may find that you need to combine the fence and loose wrapping. Remember to remove any wrapping material in the spring as growth begins. At this time other vegetation should provide food for these offending animals and the damage to the trees should stop.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email:, office: 505-865-7340, ext. 113.


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