46 FOREST TREE DISEASES. 



INCENSE CEDAR DRY-ROT. 



The dry-rot of incense cedar (called in the East 

 " peckiness " or " pin-rot " (Pis. XI and XII), caused 

 by the fungus Polyporus amarus, is one of the most 

 characteristic tree diseases. The rot consists of brown, 

 oblongated pockets, from one-half inch to several feet 

 long, filled with a brown, charcoal-like mass, and sepa- 

 rated from each other by apparently sound wood (PI. 

 XII). The fungus evidently enters through wounds 

 or knots, destroys the heartwood. but rarely attacks the 

 sapwood. The annual fruiting bodies (PI. XI) are at 

 first extremely soft and mushy, and later become cheesy 

 and somewhat tough. Originally knob-shaped, they 

 soon become bracket-shaped, with rounded tops. Fully 

 developed fruiting bodies resemble a bell cut lengthwise 

 in half. When young they are smooth and tan-colored 

 on top, with the underside a bright sulphur yellow, 

 becoming brown with age. They issue from knot holes, 

 and develop in summer and fall, occasionally after the 

 death of the tree. Being fleshy, they are devoured by 

 squirrels and insects, and the place they once occupied 

 can easily be recognized by the shot -hole effect of the 

 larvse holes in the cup-like depression of the outer bark 

 hollowed out by woodpeckers (p. 23). Seldom is more 

 than one fruiting body found on a living tree at one 

 time. Trees less than 2 feet in diameter are generally 

 free from the disease unless they are badly suppressed. 

 The lower and middle parts are the most affected. 



