chaparral (chăpərălˈ) [key], type of plant community in which shrubs are dominant. It occurs usually in regions having from 10 to 20 in. (25–50 cm) of rainfall annually and with a Mediterranean-type climate. Where the rate of evaporation is high, chaparral may be found where the rainfall is well above 20 in. Generally chaparral country has most of its rainfall in the winter. The vegetation includes both evergreen and deciduous forms, the dominant species varying in different areas. Chaparral is well exemplified in parts of the W and SW United States, although similar growth is found in many parts of the world. Climax areas (see ecology) are represented by the largely deciduous growths in Colorado, E Utah, and N New Mexico. A subclimax area extends from South Dakota to Texas and through part of the Great Basin. Among the chief species of plants in these regions are Gambel oak ( Quercus utahensis ), mountain mahogany ( Cercocarpus parvifolius ), squawbush ( Rhus trilobata ), western chokeberry ( Prunus demissa ), western serviceberry ( Amelanchier alnifolia ), and mesquite ( Prosopis glandulosa ). Evergreen shrubs are characteristic of the chaparral found in the southern half of California, especially near the coast, and extending into Nevada and Arizona. Among the dominant forms are several species of buckthorn ( Ceanothus ), manzanita ( Arctostaphylos tomentosa and A. pungens ), and the holly-leaved cherry ( Prunus ilicifolia ). A species of scrub oak ( Quercus dumosa ) is the chief deciduous form. Chaparral growth is sometimes so dense that it is almost impenetrable.
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