Power string trimmers are dangerous to trees planted in turf. The tender bark of young trees is
especially vulnerable to injury from the whirling nylon string as it cuts back tall grass at
their base. The smallest wound provides access for insects or disease to tree tissues. Spread
mulch or plant groundcovers over tree root zones to keep grass and trimmers a safe distance
from trees. If a tree is damaged, clean the wound with a sharp knife to removed tattered bark.
In most cases the plant will heal itself.