THE ROTS OF WESTERN WHITE PINE. 23 
moval of all infected slash on the sale areas. The marking rules 
should provide definite instructions to fit each distinct sale area and 
should include the consideration of the classification of stands in 
the western white-pine type and the methods of cutting employed on 
each. The pathological marking rules should specify the cutting of 
all diseased trees on a sale area where selection cutting is employed 
and the retention on clean-cut areas of seed trees free from all root, 
butt, and trunk rots, as well as from rust and mistletoe. These two 
recommendations will insure a healthier second growth in the case 
of selection or improvement cuttings, and in the case of clean-cut 
areas will insure the reserved seed trees against windfall and wind- 
break due to fungous activity. 1 In the case of the clean-cut area 
the retention of sound seed trees will also prevent distribution of 
diseases by these trees. If seed trees other than western white pine 
are reserved, the selection of sound trees will prevent infection of 
young growth by the rust 2 and mistletoe 3 diseases which are pe- 
culiar to certain tree species, such as Engelmann spruce and western 
larch, found in stands of the western white-pine type. The removal 
of all infected slash left on a sale area after logging is an important 
part of the successful control of fungous diseases. In order to pre- 
vent the spread of the diseases which have caused rot in the trees of 
the stand all infected slash liable to develop sporophores should be 
disposed of in such a manner as to check the development of the 
fungus and thus prevent subsequent sporophore production, or it 
should be destroyed outright in some manner consistent with eco- 
nomic requirements. 
SUMMARY. 
Data obtained in a study of the rots of western white pine show 
the following conclusions as presented in this bulletin : 
The three main wood-destroying fungi in the order of their im- 
portance are Trametes pini, Polyporus schweinitzii, and Formes an-. 
nosus. Most of the rot found in the tree is traceable to T . pini. 
Trametes pirn attacks all portions of the trunk, acting in some 
cases as a typical butt-rot. Polyporus schweinitzii is found to pro- 
duce a typical butt-rot, and Fomes annosus is chiefly confined to the 
roots and butt of the tree. 
1 Hubert, E. E. Fungi as contributory causes of windfall in the Northwest. In Jour. 
Forestry, v. 16, no. 6, pp. 696-714. 1918. Bibliography, pp. 713-714. 
2 Weir, J. R., and Hubert, E. E. Notes on forest-tree rusts. In Phytopathology, v. 8, 
no. 3, pp. 114-118. 1918. 
Notes on the overwintering of forest-tree rusts. In Phytopathology, 
V. 8, no. 2, pp. 55-59. 1918. 
3 Weir, .J. R. Larch mistletoe : Some economic considerations of its injurous effects. 
U. S. Dept. Agr. Bui. 317, 25 p. 1916. 
Some suggestions on the control of mistletoe in the national forests of the 
Northwest. In Forestry Quart., v. 14, no. 4, pp. 567-577. 1916. 
