10 



BULLETIN 722, V. S. DEPARTMENT OF AGEICULTUEE. 



acterized in hemlock and grand fir hj its uniformity in occupying 

 the heartwood (figs. 4 and 8). In alpine fir the rot in cross section 

 takes on a somewhat stellar development, due principally to the 

 concentration of the hyphfe along certain of the medullary rays. 



In badly decayed living trees it is invariably the case that the rot 

 not only occupies the entire heartwood of the trunk but the heartwood 

 of the branches as well (fig. 9), extending in some of the larger ones 

 a distance of several feet/ causing the formation of sporophores at 

 some distance from the trunk. 



The advance rot of EcMnodontium tindorium is very difficult of 

 detection and unless accompanied by small brownish discolorations 



or by reddish or 

 brownishstreaks can 

 not be detected with- 

 out a very close ex- 

 amination. In the 

 early stages of the 

 decay the wood as- 

 sumes a faint yel- 

 lowish, spongy tex- 

 ture. Sometimes this 

 stage is intensified 

 by the presence of 

 small, hardly dis- 

 cernible brownish 

 areaSjWhichlater de- 

 velop into the typi- 

 cal rot. The exten- 

 sion of the advance 

 rot beyond the typi- 

 cal rot varies greatly 

 according to the con- 

 ditions. Some accurate data are at hand to determine the average 

 height of the advance rot beyond the typical rot. Such data wiU 

 be found very useful to scalers in determining the amount of cull to 

 deduct from the gross scale in order to cut out all the advance rot 

 which might later develop into the crumbly decay complamed of by 

 dealers in hemlock lumber. Meinecke ^ states that in the white fir 

 (Abies concolor) of this region the advance rot produced by E.tinctorium 

 extends about 2 to 6 feet beyond the typical rot. From the data 

 collected on more than 200 hemlocks of all ages and sizes an exten- 

 sion of 1 to 5 feet has been found to be general. A single figure 



• Weir, J. R. Destructive eflccts of Trametes pini and Ecliinodontiuin tinctorum. In Phytopathol- 

 ogy^ V. 3, no. 2, p. 142. 1913. 



2 Meinecke, E. P. Forest-tree diseases common in California and Nevada, p. 52. 1914. I'nblished by 

 U. S. Department of Agriculture, Forest Service. 



Fig. 7. — Section of hemlock, showing a branch stub as a means of first 

 infection of heart-rot. The decay has commenced spreading into 

 the heartwood from the end of the branch tissue. 



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