Restrict access

About half of the root system is under the canopy of the tree. The other half is outside the edge of the branches. Restrict access to the root system by planting ground covers (right photo), building low walls, or installing fences (left photo) around the root system. This keeps people and machinery off of the soil under the canopy. People and machinery compact soil making it difficult for air to penetrate the soil. Low oxygen concentrations in soil and hard soil result in poor tree root growth.

Machinery operating under the canopy can injure roots, cut roots, and cause irreparable trunk injury if allowed to drive under the canopy. Construct a secure strong fence at the edge of the canopy to prevent any vehicles from operating under the canopy. This typically saves enough roots for a mature tree to survive the construction process provided the tree is cared for appropriate in subsequent years. This includes hiring a consulting arborist that understands how to manage and execute an irrigation, mulch, fertilization, and pruning program.

More on tree root systems.