Tree protection in Arlington County focuses on the protection of the tree’s roots. The roots are its structural support and lifeline for nutrients, oxygen and water. Protecting what is known as the Critical Root Zone (CRZ) is important for a tree to have a chance of survival. One can draw a rough representation of a CRZ as a circle of one foot of diameter per one inch of tree trunk. You can see a diagram of this here.
To protect a tree, draw the CRZ on a plan, and protect as much as possible of this zone. This is often done with six- or four-foot chain link fencing or tree pit protection boxes (depending on the size of the project) to protect tree roots during a project. Keeping this fencing up to prevent access is critical to reduce root impact. You can see an example drawing of fencing like this here.
Alternatively, one can protect the ground with root protection matting, which allows tree roots to be protected, but equipment to be driven over the roots. This is used where access to the site is still needed, but no grading or excavation is happening in the area. This can be a thick layer of wood chips or engineered solutions. You can see an example drawing of root matting here.
Failure to adequately protect a tree can lead to unwanted or unpermitted tree damage. If you think a project has removed their fencing, matting or other tree protection matters before project completion, report it by emailing urbanforestry@arlingtonva.us and an inspector will check the site for compliance.
Keep in mind that some trees may be too impacted by construction, even if they are outside of the limit of disturbance and may still need to be removed due to their root impact.