Protected root zones are an important part of a tree protection zone, typically extending out to at a minimum the edge of the tree canopy, or the dripline. In a construction or excavation scenario, tree roots are at high risk of damage from machinery and vehicular traffic, foot traffic – even from storing materials on the root zone. Sometimes the damage is not evident until years after the construction has finished.
How then, does a construction contractor manage to lay pipes, add sidewalk, provide services to the building and otherwise excavate through a protected root zone, without damaging trees that are meant to be retained?
At Capital Tree Service, we have a number of tools available to us that can provide access underground without destroying crucial roots or increasing soil compaction that would damage the health of protected trees.
Mechanical excavation:
Mechanical excavators such as backhoes are not recommended for protected tree root zones, as they would rip and crush essential roots. Hand tools are more precise, such as forks, shovels, even trowels. These tools work on a smaller scale, and can be supplemented with pruning shears, bypass blades and pruning saws where root pruning must take place.
Backfilling can take place mechanically, using clean, uncontaminated topsoil from an approved source.
Hydrovac excavation:
Hydrovac excavation is a minimally invasive technique that helps preserve large trees by using pressurized water to break up the soil and rocks between root systems. The vacuum system removes the water and debris slurry, while leaving roots and non-porous material like metal and plastic pipes. This system is precise, aiming the water at close range.
Pneumatic excavation:
Similar to hydrovac excavation, air pressure or pneumatic excavation can be used in sensitive tree root areas to break up and remove soil and other debris, digging a trench without significantly damaging the root system. Where pipes, wires, etc need to be laid, we ensure careful pruning of roots so that damage to the tree is minimized.
