294 Forestry Quarterly. 



decaying dead portions of trunks and roots of at least forty 

 species, including several conifers; Fomes fasciatus (Sw.) on 

 mature pecan trees and a few other species in the southern states ; 

 Polyporus sulphurens Fr., causing a reddish-brown rot in twenty- 

 eight host species, about one-third of which are conifers; Fomes 

 fraxinophilus Pk. on various species of ash ; and Fomes robiniae 

 Murr. on two of the three American black locusts. 



Coniferous species comprise the greater part of the natural 

 forests of the western United States and it is estimated that two 

 to ten per cent, of the mature trees are attacked by fungi and 

 rendered worthless. In some localities such species as Pinus 

 monticola, Tsuga heterophylla, Abies grandis, A. lasiocarpa, and 

 Pseiidotsuga taxi folia suffer to the extent of fifty to seventy-five 

 per cent. 



The most destructive decay of the heartwood of conifers is the 

 common "pocket rot" due to Trametes pini (Brot.) Fr. This 

 fungus probably occurs on nearly all species of conifers, except 

 junipers. The disease is said to communicate from tree to tree 

 through the roots. Polyporus schweinitzii Fr. stands next in im- 

 portance, producing in many conifers a root and basal trunk rot 

 which is of a red-brown color and breaks up into coarse cubes. 

 Fomes laricis (Jacq.) Murr. is a common heart rot in several 

 conifers, but particularly on the larch in the northwest and pines in 

 the southwest. Polyporus amarus Hedge, which causes the 

 "peckiness" of Incense Cedar in Oregon and California, is found 

 affecting fifty to ninety per cent, of the old trees. 



Of the Hydnaceae two species are mentioned, Bchinodontium 

 tinctorium^ E. & E. being abundant in the west on firs, spruce, 

 Douglas fir, and western hemlock, causing a separation of the 

 annual rings. Among the Agaricaceae a form identical with, or 

 closely related to, Lentinus lepideus Fr. occurs on living and dead 

 conifers. 



The heart rotting fungi of conifers enter largely through 

 wounds, and in the arid southwest the production of sporophores 

 seems very limited. 



Notes on Some Diseases of Trees in our National Forests. II. Phyto- 

 pathology, April 1912. 2 73-80. 



