FOREST PATHOLOGY IN FOREST REGULATION. 21 



because it is so very commonly rendered useless by dry-rot or pin- 

 rot. The numerically and economically most important species of 

 the accessible merchantable national forests in southern Oregon and 

 California are sugar pine, Jeffrey and yellow pine, Douglas fir, white 

 fir, and incense cedar. To these may be added, for certain localities, 

 lodgepole pine, red and Shasta firs, western larch, Sitka spruce, 

 western hemlock, and western red cedar. Of the six main species, 

 all three pines command good prices. They are comparatively free 

 from heart rot. White fir and incense cedar are in general so badly 

 defective that, as Clapp 1 states, they are " under present conditions 

 almost a drug on the market." Douglas fir stands in a class by 

 itself. The value of its timber is well known; in fact, it competes 

 with pine timber as far as quality for many purposes is concerned. 

 On the other hand, Douglas fir is in a far higher degree susceptible 

 to the attacks of several heartwood-destroying fungi, and, although 

 it is not classed among the inferior species, the very prevalence of 

 decay makes it less desirable than the pines, from a silvicultural 

 point'of view. 



Incense cedar and white fir are frankly classed as inferior. Whether 

 this view is correct or not, we must reckon with it as a powerful factor 

 of influence in all timber sates where these species occur. They are 

 the lower grade by-products of the factory, the production of which 

 can not be stopped; it goes on hi spite of what we may wish or what 

 we may do. The logical conclusion appears to be, then, to concen- 

 trate all efforts on detailed and comprehensive studies of the properties 

 of these by-products, desirable or undesirable, and to incorporate 

 the results in a rational system of management, rather than to attempt 

 to stop their production. The attitude of American foresters toward 

 these and similar species is undoubtedly changing. There was a 

 tune when they were considered little better than weeds, to be gotten 

 rid of as soon as possible and to be kept out of the forest wherever 

 possible. This concept is giving room more and more to a considera- 

 tion of how best to regulate the unavoidable reproduction of both 

 species and how best to utilize the timber they produce. 



The so-called inferior or undesirable species have their very definite 

 place in the ecology of the mixed forest, and many examples could 

 be cited from European experience of the disastrous results of an arti- 

 ficial change in representation of species and reduction of the mixed 

 stand to a pure stand composed of an apparently more desirable 

 species, without due consideration to the local soil and climatic condi- 

 tions. Greeley 2 seven years ago expressed the opinion that "it is 



1 Clapp, E. H. Silvicultural systems for western yellow pine. In Proc. Soc. Amer. Forest., v. 7, no. 2, 

 pp. 168-176, 1912. (See p. 175.) 



3 Greeley, W. B. A rough system of management for forest lands in the western Sierras. In Proc. Soc. 

 Amer. Forest., v. 2, no. 2, pp. 103-114, 1907. (See p. 112.) 



