THE SIERRAN MONTANE FOREST. 211 



THE SIERRAN MONTANE FOREST 



PINUS ASSOCIATION. 



Extent. — The northern limits of the montane forest of the Pacific coast are 

 extremely difficult to draw, owing to the fact that Pseudotsuga continues into 

 the Coast forest as an important dominant and also occurs with Pinus pon- 

 der osa in both the transition and the Petran montane forest. In general, its 

 northern limit is regarded as determined by the disappearance of Pinus 

 lambertiana, Libocedrus decurrens, and Abies concolor. This forest extends 

 well into southern Oregon on the Siskiyou and Coast ranges and to central 

 Oregon along the Cascade Mountains. It is found on the eastern slope of the 

 Cascades and reaches its eastern limit in the lake region. In northeastern 

 California it is present on both slopes of the Sierras, but southward from Lake 

 Tahoe it is almost confined to the western one. The northern Coast ranges 

 exhibit this community as far south as Lake County, but it yields to the red- 

 wood forest along the coast. It is fragmentary in the southern Coast ranges, 

 but becomes the typical forest at the proper levels in the San Rafael, Sierra 

 Madre, San Bernardino, San Jacinto, and Cuyamaca Mountains. It reaches 

 the southern limit in the San Pedro Martir Mountains of Lower California. 



The range in altitude is exceptionally great. In the Coast ranges of northern 

 California and Oregon the montane forest occurs at altitudes of 1,000 to 3,000 

 feet, while in the Cascades it is found at 2,000 to 6,000. In the central Sierras 

 the general elevation is 3,000 to 6,000, but this increases steadily toward the 

 south and the upper limit reaches 7,000 to 8,000 feet in southern California 

 and 8,000 to 10,000 feet in Lower California. 



DOMINANTS. 



Pinus lambertiana. Pinus ponderosa jeffreyi. Pinus coulteri. 



Pinus ponderosa. Pseudotsuga mucronata Sequoia gigantea. 



Pseudotsuga mucronata. macrocarpa. Cupressus goveniana. 



Abies concolor. Pinus attenuata. Picea breweriana. 

 Libocedrus decurrens. 



The major dominants of the association are Pinus lambertiana, P. ponderosa, 

 Pseudotsuga mucronata, Abies concolor, and Libocedrus decurrens. All of these 

 occur from the northern limit of the area in central or southern Oregon to the 

 San Pedro Martir mountains in Lower California, though the Douglas fir is 

 represented in southern and Lower California by its variety, Pseudotsuga m. 

 macrocarpa. In somewhat similar fashion, Pinus ponderosa is replaced at 

 higher levels by P. p. jeffreyi. The remaining species are all of secondary 

 importance. Pinus attenuata ranges from central Oregon to southern Cali- 

 fornia, and P. coulteri extends from central to Lower California. Both are 

 relatively xeroid and subclimax in character. Sequoia gigantea is the most 

 interesting of the dominants, but it is restricted to scattered groves on the 

 west slopes of the Sierra Nevada from Placer County to Tulare County. These 

 are the survivors of what must have been an extensive consociation in later 

 Tertiary times. Cupressus goveniana occurs sparsely through the Coast 

 region from Ukiah to Dulzura near San Diego. Picea breweriana is localized 

 in northwestern California and adjacent Oregon. 



Three species of broad-leaved trees occur so frequently in the montane 

 forest that they require mention. These are Quercus calif arnica, Q. garryana, 

 and Arbutus menziesii. They are all subclimax in character and occur com- 



