Is it OK to put a nail or a screw into a tree to mount feeders, etc., or does this damage the tree? Is there a trunk diameter at which it becomes OK to do? Are there certain tree species that are particularly susceptible to damage?
An occasional nail or screw will not cause significant damage if carefully placed into wood that is greater than 6 inches in diameter. Remember that every wound creates the potential for decay, especially in weakened trees, so keep accessories to a minimum. These sites should also be checked annually to make sure that the outward growth of the tree is not restricted in any way. If needed, remove the nail or back out the screw to allow for this growth.
Certain tree varieties should be avoided if possible. These include birch, dogwood, cherry, plum and Japanese maple.