Ponderosa pine dominates Rankin Ridge. As a drought resistant species, its extensive root system and limited need to water to make well suited to live in the Black Hills. On this arid northerly exposure, in such rocky soil, pines grow about four inches taller each year. Under ideal conditions a ponderosa pine will extend 150 to 180 feet into the air. But here its needs are marginally met, so it seldom seems to deserve the adjective “ponderous,” meaning of great size.