March 30, 2015.
I have received numerous inquiries the past several weeks regarding fruit trees that have been girdled by mice and/or rabbits. Unfortunately, this has been the worst case winter for these pests. Plentiful rainfall last growing season allowed lush grass and weed growth under trees which led to high mouse (vole) populations and the snow covered the ground for over three months straight. Most folks installed tree guards to prevent feeding but the snow was above the guards for a long time which allowed the mice or rabbits easy access to the bark. Also, it seemed that we experienced an “on” year for rabbit populations in most areas this winter.
Well, if you experienced extensive damage what can you do now? In some cases, the damage is too extensive and you should just plan to re-plant. If there was a pole next to the tree (as shown in the above photo) which prevented the critters from eating all the way around the trunk, then the trees will recover. Do not give up on these trees with even a half inch or more of bark remaining in a strip. I have seen them make it. Make sure, however, not to crop these trees this year and water these trees in the summer if it gets dry.
If the tree is damaged above the graft union, they will probably produce new shoots above the graft by early summer, which can be trained to be a new tree. This is much easier to do than the bridge grafting described below.
For those girdled all the way around, you can give up and plant a new tree or try to bridge graft across the damage. If you have rootstock suckers under the tree long enough to bridge across the damage, use them. If no suckers, collect some shoots from another fruit tree of the same type and bridge graft these on either side of the damage. You must collect these shoots (scion wood) in the next few days because it must be kept dormant until you actually graft the trees in late-April. Keep the shoots in a plastic bag in the refrigerator until you do the grafting. Do not store this wood with apples. The apples give off ethylene gas which can kill plant materials. Follow the directions for making the grafts off the internet. Seal up the grafted areas very thoroughly.
To help prevent troubles next year: keep the grass and weeds very short near the trees all summer and going in to winter. Put on tree guards for the winter. Paint the trunks up to 3 feet with half white latex paint and water. Also, it is helpful to prune some of your trees just after real winter sets in to provide the rabbits with something to feed on other than the trunks of your trees.