Tree guards can increase the survival rate of trees by protecting the trunks from damage caused by weather, animals and equipment. This Extension Note provides information on the causes of trunk damage and the kinds of tree guards you can use to protect your trees.
Tree guards help by creating a barrier between the tender bark and the foraging critters who would otherwise stop for a convenient nibble. Winter sun can also be detrimental to a tree's trunk. Clear, sunny days in winter are followed by comparatively colder nights.