Chaparral Shrublands

Geology

Parent materials of chaparral sites include deeply weathered and fractured granite, schist, diabase, and sandstone. Granites are found on more than one-half of the total chaparral area in Arizona, while diabase and sandstone comprises less than 10 %. At the Three Bar experimental watersheds, course-grained granite was found, by seismic exploration, to be weathered and fractured to depth of 20 to 40 ft (Ackermann and Walters 1965). Roots of the dominant chaparral species penetrate these materials to as much as 30 ft, although the majority of roots are concentrated in the upper few feet of soil and in the numerous fractures cutting through the decomposing rock (Hibbert et al 1974).

Topography

Chaparral shrublands in Arizona occur on rough, discontinuous, mountainous, terrain south of the Mogollon Rim (Fig. 3). The topography is characterized by steep-walled gorges and canyons. Chaparral generally occurs in a discontinuous band across the central part of the state from northwest to southeast. The type occurs at elevations ranging from 3,000 to over 6,000 ft, depending on exposure, soils, and climate.