What happens when tree roots get very large in structural soil—will they buckle sidewalks?
A. Structural soils appear to have the added benefit of allowing tree roots to grow deeper in the soil profile—so they are less likely to exploit the area of low resistance between compacted soil and pavement that exists in some sidewalks. As tree roots expand, the gravel has been observed to become embedded in the roots. Root morphology does change somewhat as roots grow around the gravel lattice—but root expansion is ultimately not impeded. Trees can be planted directly in structural soil with pavers coming up to the tree trunk. However, by planting in ordinary soil with structural soil under adjacent pavement, trees may establish better and buttress roots may be better accommodated.
