16 MISC. PUBLICATION 162, U. S: DEPT. OF AGRICULTURE 
by protecting the sources of water utilized for irrigation, for city 
water supplies, and for other purposes, are performing a function of 
even higher value to the Nation than the production of wood (fig. 10). 
Wisely managed, they can continue to perform both functions—pro- 
tection of watersheds and production of timber. 
The species most utilized are the valuable western white pine of 
the northern Rockies and the ponderosa pine which is scattered 
throughout the whole Rocky Mountain region. 
Rocky Mountain forests are made up mostly of coniferous species. 
Among these, in addition to the two just mentioned, are Douglas-fir; 
western larch; western redcedar; western and mountain hemlock; 
lodgepole, mber, whitebark, bristlecone, and pinon pines; alpine, 
F -33406A 
FicuRE 10.—A forest-covered watershed in the Rocky Mountains. The forests 
of this region play an important part in watershed protection. 
white, and lowland white firs; Engelmann, blue, and white spruces; 
junipers; cedars; and cypresses. Aspens, cottonwoods, oaks, walnut, 
sycamore, alder, and boxelder are some of the few hardwoods of this 
region. 
Paciric Coast Forest REGION 
The Pacific coast forest region extends from the Canadian border 
through the western half of Washington and Oregon and into Cali- 
fornia. In the southern portion of California the timbered lands are 
on the higher elevations, surrounded by areas of low brush-type forest 
or chaparral. 
What are perhaps the heaviest stands of timber in the world are to 
be found in the Pacific Coast States. They contain the last great 
commercial bodies of softwood virgin timber remaining in the United 
