Creating “Safe Zones” for Trees

We are familiar with keeping our families and our children safe – but keeping our trees safe? And what exactly is a "safe zone"? A safe zone is an area around a tree trunk where grass and weeds don't grow to prevent damage to trees from the use of lawn equipment close to the tree trunk.

The idea is, if you aren't mowing or weed-whacking close to tree trunks, you are less likely to come into contact with them. Weed whackers with their nylon whips can cut through the bark and into the vascular layers, essential to tree health and growth. The damage often extends all the way around the tree.

Cuts in the trunk that go beyond the bark will first disrupt the downward flow of sugars from the leaves, leaving the roots without needed resources for health and growth. Then, if wounded just a little further, the flow of water and minerals from the roots to the leaves is interrupted. Damage to these systems will also affect tree support, storage ability, and defense against the spread of disease and decay.

Provide a safe zone for all of your trees and prevent one second of "oops" from wiping out a sizeable investment of money and time. "Better to be safe than sorry" is definitely true for trees and lawn maintenance equipment.

Community Canopy recommends that a grass and weed-free safe zone be established at least 18 inches out from the trunks of trees. You could create an outer, 36-inch diameter barrier, such as plastic edging or cement curbing, in this instance.

If there is already turf around a tree trunk, establish the safe zone by removing the grass and roots by hand. A composted mulch layer will help reduce the germination and growth of weeds. Mulch has many added benefits, such as maintaining soil moisture and improving soil fertility. Mulch should be at least 2, but no more than 4 inches deep, tapering to zero as it approaches the tree trunk. Periodic maintenance will be needed.

The safe zone message with graphic above is available in the Parks Department at City Hall, and is being distributed to local homeowners' associations and landscapers. More information can be found at