Mice like to hide in dead grass and weeds around the trees, especially close to the trunks. They will often tunnel near the soil surface and feed on the tree bark. You can check for mice by placing baited mouse traps in PVC or other pipe near your trees. Insert the traps far enough so that pets are unable to reach the trap. Check the stations about once a week and reset traps if necessary.
Mouse damage can be severe enough to kill trees that are old enough to bear fruit. Clear dead grass and weeds away from your trees and monitor for mice if you are using mulch around your fruit plants. (Ward Upham)