Tree Health and Your Friendly, Backyard Ant

Spring is just around the corner. As we look forward to warmer days and spring flowers and garden projects, our excitement builds. Spring is also a time when the cold-blooded animals start to wake up and, well, start bugging us. One group of insects that can be frequently misunderstood and maligned is ants. It’s the time of the year that you may be frustrated with ants finding their way into your home. Ants in your house may not be a welcome part of the warmer months, however, ants in your yard — and on and around your trees — are a different story.

Ants are important in the ecosystem for several reasons. They frequently predate other insects; they can be important for seed dispersal; they are pollinators for many plants; they can predate pest insects. If you love your trees and want to keep them healthy, consider that ants play an important role in having healthy roots.

A majority of tree health issues that I see in urban forests are soil health issues.  The biggest soil health issue I encounter is soil compaction (lack of pore space for air to get to the roots and water to drain through the soil.) Compacted soil can lead to limited and shallow roots for your trees. Well-aerated soils mean better tree root systems. Ants are one of the best natural soil aerators out there. Some say they do more to aerate the soil than earthworms. As ants build nests, they open up the soil and bring organic matter underground. If you want deeper and more abundant tree roots to anchor your trees and keep them healthy, you should be glad you have some ants in your yard. Sure, there can be some bad actors in the ant world. You don’t need to travel very far southeast of Richmond before you’ll encounter the dreaded and invasive fire ant. Carpenter ants can be a sign of decay in trees (although they do not cause the decay). But in general, a healthy ant colony under the canopy of your tree is a good thing. It usually means healthier soil, and thus, a healthier tree.