PINE DISEASES 291 



with the occurrence of the disease. So far no satisfactory 

 work has been carried on to explain the real factors involved. 



Refeeenceb 



Graves, A. H. A preliminary note on a new bark disease of the white 



pine. Mycologia 6 : 84-87, pi. 120. 1914. 

 Haasis, F. W. Dying of young pines in circles about anthills. Jour. 



Forestry 16 : 763-771, figs. 1-5. 1917. 



Pecky Wood-Rot 



Caused by Trameies pini Fries 



This is the most destructive wood-rot of conifers in the 

 forests of the United States. It is commonly known as ring- 

 shake, red-rot, pecky wood-rot or peckiness. The ring-shake 

 character of this rot is more common in pine than in the other 

 conifers affected. Infection takes place at branch wounds 

 where heartwood is exposed. The mycelium penetrates 

 through the wood of the branch stub into the heart of the tree. 

 Here it spreads rapidly upward and downward but in the radial 

 direction it spreads more slowly. The result is that a few 

 annual rings of the wood are often destroyed before the wood 

 within and without the affected layers is penetrated. The 

 common name ring-shake is, therefore, appropriate. In the 

 other conifers, however, the mycelium is usually less restricted 

 and often no shake is produced. The pine wood, being rich 

 in resinous materials, escapes the damaging action of this fungus 

 in the sapwood and bark ; and pines, therefore, are rarely killed 

 by it. As the mycelium advances toward the bark, quantities 

 of resin are liberated. It accumulates in the sapwood and bark, 

 making these tissues immune to the further penetration of the 

 fungus. The white lined pockets of decay occur in the heart- 

 wood. The discussion of this fungus as given under spruce 

 diseases (see page 324) is in every way applicable to the pine, 

 except as to the points mentioned above. The sapwood and 



