Major Plant Communities in a Transect of the Sierra Nevada Mountains of California

Abstract

Among the ecological problems in the Sierra Nevada Mountains of eastern California are the contrasts of physiography, climate, and vegetation on the two sides of the mountains, the differences due to their wide range in altitude. and the interactions between local environments and plant communities. A large amount of information pertaining to these problems is to be found in the works of Jepson ('IO, '25), Abrams ('23), Smiley ('I5, '2I), Merriam ('98), Tidestrom ('25), Shantz ('25), Sampson ('25), Sudworth ('o8), Clements ('20), Harshberger ('I I), and others. The recent book on the animal life of the Yosemite by Grinnell and Storer ('24) describes conditions in a belt across the Sierra some distance north of the transect here presented, which traverses the middle part of the range. Some of this region was already known to the writer before beginning, in the spring and summer of I926, the determination and mapping of the major plant communities in a representative belt transect. This was intended from the outset to constitute a foundation survey on which additional and more detailed investigations might be based. The location of the transect chosen as typical of the middle Sierra Nevada is shown in figure I. Except for its west end, it is included in the Sierra National Forest and the Inyo National Forest. Most of it is in Fresno County, although a part of Madera, Mono, and Inyo counties is included. The transect is 7 miles wide and 8o miles long, extending from, the floor of the Great Valley on the west to the Owens River Gorge on the east. It is very nearly at right angles to the long axis of the range, and therefore lies in a southwest to northeast position. The country within this strip is considered typical of the middle Sierra Nevada rather than of the southern Sierra.