Do the rings we see in some of the petrified wood represent annual growth rings? No. As sub-tropical to tropical trees, they probably grew year-round. There would need to be a growing season versus a non-growing season to create annual growth rings. How tall were these trees? Two trees in the Long Logs area of the Rainbow Forest measure 137 and 141 feet long. This indicates that some of the trees may have approached at least 200 feet (61 m) tall when alive.