The Coastal Siskiyous ecoregion consists of highly dissected mountains with a wetter and milder maritime climate than elsewhere in the Klamath Mountains ecoregion. Elevation varies from 600 to 5,300 feet (183 to 1,615 m). Productive forests composed of tanoak, Douglas-fir, bigleaf maple, California laurel, and some Port Orford cedar cover its mountainous landscape, with chinkapin, salal, rhododendron, and swordfern; tanoak is more common than elsewhere in Oregon. Broadleaf evergreens, such as tanoak and madrone, quickly colonize disturbed areas, making it difficult to regenerate conifer forest growth. Xeric soils derived from Siskiyou rock types are characteristic; udic soils which support western hemlock and Sitka spruce are present but are less common than in the wetter Coast Range ecoregion to the west. The region covers 853 square miles (2,209 km2) in Oregon, including portions of the Rogue River – Siskiyou National Forest and the Kalmiopsis and Wild Rogue Wilderness wildernesses. Contiguous areas in California have not been mapped yet.