28 THE BROAD-SCLEROPHYLL VEGETATION OF CALIFORNIA. 



Above the ranges of the dominant trees of the Montane Forest the 

 chaparral species become gradually fewer. At least one (Ardosta- 

 phylos nevadensis) reaches timberline in the Yosemite region (39). 



The following list includes those species which are of importance 

 in the conifer forest chaparral in various parts of its range. Many- 

 others, of course, occur occasionally, especially where the range of 

 the formation overlaps that of another. Species marked with a 

 single asterisk (*) are of importance also in the broad-sclerophyll 

 forest, those with two asterisks (**) in the climax chaparral, and 

 those with three in both. 



Sclerophylls. 



Castanopsis chrysophylla minor.* Pasania densiflora echinoides.* Arctostaphylog mariposa. 



sempervirens. Rhamnus californica.**' nevadensis. 



Quercus chrysolepis.*** Ceanothus cordulatus. patula. 



sadleriana. velutinus. pungens. 



vaccinifolia. Garrya fremontii. viscida. 



wislizeni.*** Arctostaphylos drupacea. 



Decidu(ms. 



Corylus rostrata californica. Amelanchier aloifolia. Cercis occidentalis. 



Quercus breweri. Prunus demissa. Acer glabrum. 



garryana. emarginata. Ceanothus integerrimus. 



kelloggii.* subcordata. sanguineus. 



The conifer forest chaparral association is at least as variable as 

 the climax chaparral. This is due in part to great variation in habitat 

 and also in an important degree to what may be termed accidental 

 causes, for since the community owes its existence in large part to 

 the frequent destruction of the forest by fire, the population of a 

 given area must depend largely upon what species are producing 

 seed in its immediate vicinity. The association has been carefully 

 studied by the U. S. Forest Service, since its occurrence within the 

 belt of merchantable timber gives it great economic importance. 

 A number of reports have been published (see introduction) and 

 many more are still in manuscript, and to these I have had access 

 through the kindness of the officials of District 5 in San Francisco. 



Since the work of the Forest Service upon this community greatly 

 outweighs mine, and since more of it is soon to be published, I will 

 not attempt detailed subdivision. A few general features are worth 

 pointing out, however. In the lower and drier portion of the yellow- 

 pine belt of the Sierras one combination is of great importance. 

 This is made up of Arctostaphylos viscida and Ceanothus integerrimus, 

 the former being especially conspicuous because of its beautiful gray 

 foliage. It is particularly widespread in the regions surrounding 

 the old placer diggings, where the timber was cut and burned 

 off more than half a century ago. In the upper and moister por- 

 tion of the pine belt and the lower part of the Subalpine Zone 

 the areas of chaparral show greater floristic diversity, and a great 



' Principally in its two vaiieties, R. c. tomentella and R. c. rubra. The latter is deciduous. 



