Trimming grass around a tree can be a perilous task--for the tree. Extreme care mush be taken to prevent nicking, gouging or stripping off tree bark by the cutting blades, wheels and whips of modern landscape equipment. The strength, thickness, density and adhesion of tree bark varies widely by species. Damaging or removing even a portion of the bark cannot only mar the appearance of the tree but also provide an entry point for pests and disease that can cause serious problems for the tree and for you, its caretaker.
Halt your lawn mower when you come within a foot of the trunk of a tree. Any closer can allow the cutting blades to come into contact with swelling surface roots at the base of the trunk or the tree's bark.
Refrain from using any mechanical motorized edging tool, weed whacker, string trimmer or similar tool anywhere near the base of the tree. Even with careful and deliberate use, any slight accidental movement can cause lacerations that permanently mar the tree bark and damage the trunk wood.
Trim the lawn immediately surrounding landscape trees with manual long-blade hand pruners designed for use on grass or thin garden material.
Hold the pruners perpendicular to the grass blades and parallel to the tree trunk as you cut your way around the base of the tree. Trim the grass blades to a height level with the surrounding lawn grass to provide a seamless look.
Collect the clippings or brush them down in between the grass blades with your hands to act as a natural fertilizer.