152 THE CULTIVATED EVERGREENS 



The wood-rots which attack coniferous trees are too numer- 

 ous to be dealt with in detail, but all conform more or less 

 closely to the general description given above. The following 

 are some of the more important fungi which are responsible 

 for these rots : 



Trametes pini, Fries, causes a destructive rot of fir, spruce, 

 larch, and pine. The heartwood, sapwood, and bark are 

 attacked and trees are often killed. The common name for 

 the disease produced is "ring-shake," on account of the fact 

 that complete annual rings are rotted. 



Fomes pinicola. Fries, occurs less frequently on living trees, 

 but is common on those which have been killed or weakened 

 by other agencies. It causes a sapwood rot in which the wood 

 becomes powdery and red-brown in color. 



Fomes roseus. Fries, attacks fir, juniper, larch, spruce, pine, 

 hemlock, and arbor-vitae, causing a brown heart-rot. 



Echinodontium tindorium, Ellis and Everhart, is important 

 in the West where it causes a peculiar heart-rot in fir, spruce, 

 and western hemlock. The spring wood is particularly at- 

 tacked, causing the annual rings to become separated into 

 disconnected cylinders. Finally the summer wood also is 

 destroyed, leaving the trees hollow. 



Polyporus Schweinitzii, Fries, causes a rot of the heartwood in 

 the roots and butts of pine, fir, spruce, hemlock, larch, and arbor- 

 vitse. It often results in the uprooting of the trees by wind. 



Armillaria mellea, Quelet (Fig. 19), is more common on 

 deciduous trees but attacks pine, larch, and hemlock, causing 

 a rot of the bark and sapwood of the roots. The rot may also 

 extend to the butt. The final result is usually the death of 

 the trees attacked, but this may not occur for several years. 



Fomes juniperinus, Schrenk, is responsible for a heart-rot 

 of junipers which often makes the trees hollow. 



