our mulch mat suit different tree sizes and not be decomposed or blow away. tree rings ,tree guards ,tree grates .materails : rubber mulch ,rubber buffingssize ... " diameter x 0.75"24" diameter x 0.59"rubber tree ring is made of recycled rubber, rubber buffings using compressed ... of the ground. It stops hurting the tree and grass. Tree ring will grow as the tree grow, becoming one as the nature ...