THE ROTS OF WESTERN WHITE PIlirE. 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.^ In the case of the clean-cut area 

 the retention of sound seed trees will also prevent distribution of 

 diseases hj 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^ and mistletoe^ 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 mfected 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 destroj'ecl 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, Polypoi^s schweinitzii, and Fomes an- 

 nosus. Most of the rot found in the tree is traceable to T. pini. 



Trcumetes pini attacks all portions of the trunk, acting in some 

 cases as a typical butt-rot. Polypo^ms schioeinitzii 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 Xortbwest. In Jour. 

 Forestry, v. 16, no. 6, pp. 696-714. 1918. Bibliography, pp. 713-714. 



2 Weir, J. R., and Hubert, B. 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. 



2 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. 



