A flexible, porous and durable tree well skirt and a sidewalk structure
are made of a cushion base of butadiene rubber and a wear layer of
ethylene propylene diene monomer (EPDM). The butadiene rubber is mixed
with an isocyanate polyurethane binder and spread on the ground around
the tree to form the cushion base of the tree well skirt. The EPDM is
mixed with an isocyanate polyurethane binder and spread over the cushion
base to form the wear layer. The cushion base and wear layer structure
used for a sidewalk is spread over a stabilized porous base.