Apple Tree Girdling

• Rabbits chew through the bark, damaging the phloem layer of tissue just beneath the bark. This layer is responsible for water and nutrient transport from the roots to the tree. Damaging that layer around the tree's circumference will girdle the tree and kill it. According to New Mexico State University, however, even young apple trees can survive the removal of a vertical strip of bark that is less than one-quarter the circumference of the tree, but anything greater than one half the circumference and the tree will likely die.
  
  

Tree Protection

• Chicken wire tree wraps are an effective method of protecting apple trees. Wrap trees in the fall. The wrap should extend as far up the tree as a rabbit can reach standing on his hind legs, which is about 36 inches. That height, however, doesn't take snow cover into account, and rabbits can perch on top of the snow to gnaw at apple bark. If you usually get lots of snow, take that measurement into account. Use chicken wire or hardware mesh and make sure to bury the wrap at least 4 to 6 inches underground. Rabbit repellents should cover the trunk and lower branches. They are available in spray and paint forms.
  
  

Habitat Modification

• Rabbits live in bushy areas with tall grass and plenty of places to hide. They also like to live around fencerows that usually provide such a habitat. Clear brush and weeds and cut tall grass around the orchard's perimeter to remove such hiding places. If you hunt or know someone who does, hunting rabbits during the winter is another way to keep the population low enough to prevent apple tree damage.
  
  

Repair

• There is a slight delay between bark damage and tree decline, during which it is possible to repair the wound and assist the tree in growing new tissue. This process is known as bridge grafting because the patch carries food across the wound. Bridge grafting involves placing new growth from upper twigs or branches on the wound and securing them under healthy bark so they lay flat.