DRY-ROT OF INCENSE CEDAR. 23 



dish purple, usually began at the ground level, extending up the heart- 

 wood to a minimum height of 2.6 feet and a maximum height of 31.4 

 feet. Of these trees 39 had open or healed-over wounds, mainly 

 caused by fire, offering or having offered a means of access for the 

 dry-rot, but the remaining 45 were without indications of wounds, 

 the only possible mode of entrance for the decay being through 

 branch stubs. It would be highly improbable that all of these trees 

 could be infected by the dry-rot fungus without showing any indica- 

 tions of decay, so the conclusion is obvious that purple coloration 

 may exist unaccompanied by Polyporus amarus. 



In all, 510 trees with typical dry-rot alone or in conjunction with 

 secondary decay were worked up at Sloat, Strawberry, and Crockers 

 Station. Notes on 25 of these were incomplete so far as purple 

 coloration is concerned, so they drop out of consideration. All but 

 17 of the remaining 485 had purple coloration accompanying the 

 decay. In certain cases the coloration did not extend over the entire 

 decayed area, running out before the decay ended, or else isolated 

 pockets of dry-rot were found outside the area of coloration. In the 

 17 cases of dry-rot unaccompanied by any coloration, the decay as a 

 rule was negligible. In four of these trees, however, there was a loss 

 in volume caused by the dry-rot of 7.1, 21.3, 39, and 67 per cent, 

 respectively, without any coloration being visible, indicating that 

 serious decay can exist apart from the purple coloration. 



Of the 59 infections of the Trametes pini decay, 4 became impos- 

 sible of consideration because of incomplete notes. Of the remaining 

 55, 12 were unaccompanied by purple coloration, but all of these 

 except two were very superficial infections. Even in these two the 

 amount of cull was very small. This decay had already been shown 

 almost invariably to follow wounds in the trees; hence, it becomes 

 quite reasonable to presume that the absence of purple coloration 

 was brought about in most instances by the change in the physical or 

 chemical condition of the heartwood induced by the influence of the 

 wounds. 



Where the typical decay and the Trametes pini decay were inter- 

 mingled the coloration was almost invariably present, although not 

 always throughout the entire infected wood. This was also the case 

 with the brown dotlike pockets. However, these data should not be 

 judged as more valuable than indications, since the number of cases 

 available was relatively few. 



Secondary rots comprised 43 infections; only 12 of these were in 

 conjunction with purple coloration. The 31 without coloration only 

 yielded one cull case; the amount of unmerchantable volume was 

 very small, and furthermore these secondary rots were almost invari- 

 ably in connection with healed or open wounds. 



