Root Collar Excavation is the removal of existing or excess soil, to inspect the root system of the tree. Many times in the landscape trees are planted too deeply. Soil over the root flares can cause the bark and cambium layer in the trunk and root flares to decay. The trunk cannot tolerate constantly moist soil like root tissue can. Many times girdling roots, planting baskets or we find rope around the root ball of trees while doing a root crown excavation. Girdling roots grow around the main stem and choke the tree. These roots can restrict the movement of water, plant nutrients and stored food reserves.
The root collar is part of the tree's trunk. Unlike roots, the trunk is not specialized to resist constant soil moisture. The movement of oxygen and carbon dioxide in and out of the phloem (inner bark) is inhibited by this water. The root flare is the portion to the tree where the trunk widens at the base as it transitions to the root system. This flare occurs at the natural grade of the soil. It is of critical importance that this level be maintained.