One of the easiest ways to kill a young tree is to damage the trunk with your lawnmower or weed eater. There are ways to protect your tree and prevent this from happening. First, maintain a mulch ring around your tree. Second, use a trunk protector. Thirdly, make sure that whoever is maintaining your landscape knows better than to damage your tree (i.e., Landscape Companies, HOA, Your teenager).
A mulch ring around the base of your tree can help your tree in multiple ways. Mulch helps hold moisture longer in soil. Natural mulch is best because as it breaks down and decomposes it incorporates organic matter into the soil. Try to avoid rubber mulch if possible. The mulch will keep the weeds and grass from growing up next to your tree which does two things. It prevents the competition you get from grass and weed roots. They will steal the nutrients and water that should be going to your tree. It also forms a barrier around the trunk of the tree that keeps mowers and weed eaters away from it. When trees are young their thin bark is fragile and can easily be damaged. This can cut off the flow of water and nutrients to the canopy of the tree and lead to death. When the bark of a tree is damaged it can leave an open wound for disease and fungus to enter through. Now that your tree is stressed and possibly has an infection it is more susceptible to have other problems.
Trunk protectors can be used to help protect the trunk if needed. Ideally, the mulch can keep the weed eaters and mowers far enough away to protect. You want to make sure that the trunk protector you get is not too tight around the trunk. Disease and fungus can form behind the trunk protector and affect your tree. Trunk protectors are also good for protecting against rodent damage as well. Rodents (i.e., skunks, raccoons, and squirrels) can chew on the bark at the base of the trunk and girdle your tree.
You as the homeowner need to make sure that your landscapers are not damaging your trees. Ideally, all landscapers should add mulch rings to newly planted trees so they don’t damage the trunk but unfortunately, most companies will not use mulch unless you tell them you want it. You want to have 2-4 inches deep of mulch around your tree. Making sure to keep the mulch pushed back from the trunk. Think of mulching like a donut shape and not like a volcano.