the 1830's, mentioned that the accounts of the large size of the 

 lakes in the Central Valley were "exaggerated"; neither of the 

 lakes, he stated, was over 100 miles (161 km) long! However, the 

 Freshwater Marsh plant community has become considerably 

 more restricted in its distribution than it was in former times. 

 Much of the decrease in marshlands in the Central Valley has 

 been in response to the increasing aridity of the California climate, 

 but the natural process has been overshadowed by the draining 

 of marshes by man in order to increase the expanse of land avail- 

 able for agriculture, by withdrawing ground water for irrigation 

 purposes, and by the diversion or retention of water by dams in 

 the Sierra and the Coast Ranges. 



Montane Forest (Plate llB-D;Map 4) 



In continuing the eastward transect across northern California, 

 as we move from the grasslands and marshes of the Central Val- 

 ley upward into the foothills of the Sierra Nevada, the first plant 

 community encountered is the Valley and Foothill Woodland, 

 which was discussed earlier since it also occurs in the Coast 

 Ranges as well. After leaving the Valley and Foothill Woodland, 

 with a further increase in elevation coniferous trees begin to ap- 

 pear in abundance. At this point we have entered the Montane 

 Forest. In the Sierra Nevada, the Montane Forest begins at ap- 

 proximately 2,000 feet (610 m) in elevation (depending on lati- 

 tude and local ecological conditions). It may extend up to 8,000 

 feet (2,438 m) in the southern California mountains. Montane 

 Forest also occurs in the North Coast Ranges and the Klamath- 

 Siskiyou region, and extends into northeastern California. Per- 

 haps the most common and conspicuous conifer in the Montane 

 Forest is Ponderosa Pine (Pinus ponderosa). Also present are 

 Incense Cedar (Calocedrus decurrens). White Fir (Abies concolor), 

 Douglas Fir (Pseudotsuga menziesii). Sugar Pine {Pinus lamber- 

 tiana), and in some areas Coulter Pine (P. coulteri). In some por- 

 tions of the Sierra Nevada, the Montane Forest is locally domi- 

 nated by Sierra Big Tree (Sequoiadendron giganteum, Plate 1 ID) 

 which, like its coastal cousin, is a narrow endemic with a long 

 fossil record. The present scattered distribution of Big Tree can 

 be traced back to the patterns of Pleistocene glaciation several 



101 



