tree species that occur in the redwood region but which generally 

 do not occur in a vigorous state in association with Coast Red- 

 wood. Because of the intolerance of Coast Redwood to prolonged 

 drought, shallow soils, and hot climates, this species is replaced 

 on the eastward side of its range (in many areas) by Douglas Fir, 

 a species which tolerates these conditions rather well. Thus, the 

 mosaic effect of local tree dominants in the North Coastal Forest 

 can be explained by the individual ecological characteristics of 

 the local dominants as well as of their potential competitors. 



Chaparral (Plate 8C, D; Map 3) 



Another of the plant communities that occur along our tran- 

 sect is Chaparral. Chaparral is one of the most characteristic plant 

 communities of California, and occurs only in the California 

 Floristic Province. Chaparral is a broad-leaved sclerophyll type 

 of vegetation. Sclerophyll means "hard-leaved", in reference to 

 the hard, stiff, thick, heavily cutinized, and generally evergreen 

 nature of the leaves of chaparral shrubs. This type of leaf is char- 

 acteristic of many xerophytic shrubs. The shrubs that dominate 

 Chaparral are generally rather low, the average being between 3 

 and 6 feet (0.9 and 1 .8 m) tall, although occasional individuals 

 may reach up to 10 feet (3 m). Chaparral is dense, often impene- 

 trable, and notably deficient in trees and herbs. Indeed, the 

 ground underneath or among chaparral shrubs is often completely 

 devoid of herbaceous plant species. This may be due in part to 

 shading or to competition from roots of chaparral shrubs for 

 water, although much of this phenomenon is probably also due 

 to allelopathy, since some chaparral shrubs (e.g., C\v2m\SQ , Adeno- 

 stoma fasciculatum) are known to exhibit allelopathy. 



The word chaparral is of Spanish origin. In Spain, "chaparro" 

 refers to a scrub oak. The suffix "-al" means "a place of. Thus, 

 chaparral is "a place of scrub oak". In CaUfornia, the term 

 Chaparral came to be applied to a specific type of plant commu- 

 nity consisting of a dense growth of evergreen, hard-leaved shrubs, 

 although taxonomically these shrubs are mostly not oaks. Char- 

 acteristic species of Chaparral are Chamise or Greasewood 

 {Adenostoma fasciculatum, Rosaceae), California Holly or Toyon 

 {Heteromeles arbutifolia, Rosaceae), Holly -leaf Cherry (Prunus 



92 



