THE BROAD-SCLEROPHYLL VEGETATION OF CALIFORNIA. 73 



The broad-sclerophyll climaxes, including the broad-sclerophyll 

 forest and the climax chaparral, will shortly be treated in detail. 

 The alpine meadow climax belongs to the highest summits of the 

 Sierras. The desert climax occurs east of the Sierras and the moun- 

 tains of southern California. The basin sagebrush climax enters 

 the eastern part of the State to some extent, and the coastal sagebrush 

 is locally important in the interior valleys of the south. It is possible 

 that the Great Valley or a part of it is climax grassland. The 

 coastal sagebrush and the grassland are in extended contact with the 

 climax chaparral. 



THE BROAD-SCLEROPHYLL CLIMAX FOREST. 



Discussion of the climax nature of the broad-sclerophyll forest 

 involves considerable difficulty. Its distribution is patchy, i. e., 

 no extensive area is completely dominated by it. In parts of the 

 region elements of other vegetation types are mingled with it, giving 

 the appearance of a transitional type. Its natural distribution has 

 plainly been restricted somewhat, especially by fire. 



The range of the broad-sclerophyll forest is practically coextensive 

 with that of the climax chaparral, and over most of the region there 

 is sharp alternation between the two. The forest is least important 

 southward. In the Cuyamaca Mountains the chaparral covers all 

 slopes of the lower altitudes, the forest being confined to the steepest 

 ravines and similar situations where the moisture conditions are 

 unusually favorable. As we go northward, or upward in the moun- 

 tains, we find the forest increasing in importance. In the central 

 Coast Ranges it is the regular covering of the steeper north-facing 

 slopes, the chaparral being confined to south slopes and summits. 

 In the San Francisco Bay region the two are roughly equal in impor- 

 tance, and still farther northward the forest continues to gain. 

 Here, however, a new complication arises. Pseudotsuga mucronata 

 is present in the most mesophytic situations and rapidly increases 

 in importance northward. In some places it forms pure growth, but 

 oftener occurs in mixture with the broad-sclerophyll trees, the chapar- 

 ral still holding the south slopes, but steadily decreasing in impor- 

 tance. Finally, we encounter a clear dominance of Pseudotsuga, 

 with the broad-sclerophyll trees forming an understory. Ascending 

 one of the southern mountain ranges, we meet with a similar tran- 

 sition, the broad-sclerophyll forest gaining over the chaparral and 

 finally merging with a forest of Pseudotsuga, the species of the last 

 being different (P. macrocarpa) , but to a degree ecologically equiva- 

 lent to the northern one. In short, the broad-sclerophyll forest is 

 plainly unable to control in the south; it increases in relative impor- 

 tance northward and upward, but just as it begins to show decided 

 signs of dominance over the chaparral, it comes into competition 

 with a coniferous element, to which it soon becomes subsidiary. 



