City of Atlanta Tree Prescriptions


The City of Atlanta Tree Ordinance protects any tree over 6 inches in diameter. It is often the case during a building project, that trees over 6 inches in diameter are negatively impacted by construction activities but not killed. In very specific circumstances, the City allows impact to occur if the homeowner hires a private arboriculture firm like Arbormedics to care for the trees during the building project.


The first step in this process is to use the City of Atlanta’s formula to calculate the building project’s impact to the tree. The City formula stipulates that the tree’s root zone (Critical Root Zone, CRZ) is equal to a circle with radius (in feet) equivalent to the trunk diameter measured (in inches) at 4.5 feet above ground level. For instance, the critical root zone of a 24 inch Oak would be a circle surrounding the tree with a radius of 24 feet. The impact to the CRZ is calculated as a percentage of the impacted area divided by the total area of the circle.

If the impact percentage is less than 0-19%, the City does not automatically require you to hire an arborist to help the tree.

If the impact percentage is 20-32%, the City often allows you to proceed as long as you hire a firm like Arbormedics to perform a “Tree Prescription” or “Silvacultural Prescription” (different names for the same procedure).

If the impact percentage is 33% or more, the tree is declared “lost” and you will be required to plant trees to maintain the overall tree canopy in Atlanta, or you will be required to pay recompense which will be used to plant trees on public land.



A Tree Prescription is two things. First, it is a set of recommendations for the tree during the construction process. The most common recommendations are treatments that will repair the damaged root system and encourage new root growth. Second, the tree prescription consists of the actual implementation of these recommendations and treatments. A Tree Prescription is not just paper! The tree needs to receive its medicine as part of the process!

The City of Atlanta requires us to provide them with very specific paperwork documenting our tree prescription on your property. One required component is a “paid in full receipt” showing that the property owner has paid us for our services and that the services are either complete or in process. People often find this part of the process disconcerting. The reason the City requires the “paid in full receipt” is that over the years builders became notorious for signing contracts with arborists to do the required work, and then calling the arborist as they left City Hall with their building permit to cancel the actual work before it ever occurred!



At Arbormedics, we offer full turnkey Tree Prescription services to guide you through the process from start to finish. This includes the initial site visit, prescriptive recommendations and tree care treatments.