Andalusia possesses the most-varied terrain and vegetation in all of Spain. Striking contrasts exist between alpine mountains and pine forests at high elevations, arid and barren deserts, and fertile irrigated plains that support plantations of subtropical fruits. The topography of Andalusia is divided by mountain ranges into several distinct zones, each running southwest to northeast. The Sierra Morena is the northernmost range, crossing the northern parts of the provinces of Huelva, Sevilla, Córdoba, and Jaén. These mountains present a relief of desolate ridges punctuated by narrow valleys.