[Illustration: FIG. 1. Southern oak woodland association. The open
leaf-strewn floor of the woodland lacks shelter for ground-dwelling
rodents and the population of rodents is small. _Peromyscus boylii
rowleyi_ is the commonest rodent. Photo March 10, 1952, in Evey Canyon,
2700 feet elevation.]
[Illustration: FIG. 2. Yellow pine forest association, composed largely
of yellow pines, white fir, and black oak. Photo April 27, 1952, at Big
Pines, 6800 ft. elevation.]