26 BULLETIN r>44, U. S. DEPARTMENT OF AGRICULTURE. 



and fungous attacks. Wet snow and sleet are also responsible foi 

 considerable damage to young spruce. The weight of snow will 

 often bend the young trees over beyond the point where they can 

 recover their erect position, 



FUNGOUS GROWTH. 1 



Spruce is susceptible to injury by fungous growths of many sorts, 

 which gain entrance into the wood through wounds resulting from a 

 variety of causes. Some of the fungi can not thrive on a thrifty 

 growing tree, but are secondary causes of death. Others, however, 

 are unselective as to the thrift of their host. 



Three root parasites 2 which attack the spruce are Polyporus 

 schvjeinitzii, Poria (Polyporus) subacida, and Fomes (Polyporus) 

 annosus. Polyporus sckweiniizii, the worst of these, is very preva- 

 lent throughout the northern spruce and fir forests, where it attacks 

 old and young trees alike, as does also Poria subacida. To what 

 extent Poria subacida is the cause of the death of the tree, however, 

 is not known, nor whether it attacks perfectly healthy trees; but it is 

 known to be particularly destructive to dead timber. Fomes 

 annosus, although very destructive in the forests of Europe, has not 

 been accounted so in our eastern forests up to the present. These 

 fungi usually spread through the soil and gain entrance to the tree 

 through the roots, which makes them difficult to detect and still more 

 difficult to combat. While it will not do to hunt out diseased trees 

 as is done in Europe, it may prove of advantage whenever an infected 

 group of trees is found in lumbering to cut all nearby trees. Decay 

 will not, in many cases, have extended so far up the trunk as to 

 prevent one or two merchantable logs being obtained. 



Three wound parasites 2 which do a great deal of damage to spruce 

 are Trametes pini abietis, Fomes (Polyporus) pinicola, and Polyporus 

 sulpliureus. They gain entrance to the tree above ground through 

 wounds on the trunk and branches, and spread up and down the 

 trunk from the point of infection to the topmost branches and to the 

 roots. Trametes pini abietis very commonly attacks both the 

 heartwood and sapwood of spruce and literally riddles them with 

 small holes. Fomes pinicola, while it attacks living trees, is generally 

 found on those individuals which have a weakened vitality, and is 

 one of the first to si ill'' on such trees as have met death through 

 other causes. Polyporus sulpliureus is found on spruce, but is more 

 prevalent on hardwoods. There are undoubtedly many others of 



1 Those desiring detailed information concerning fungous diseases and how to combat them should com- 

 municate with the Division ol Forest Pathology, Bureau of Planl Industry, Washington, D. C. 



*VonScbre a in: "Some Oisc-iscs of Now England Conifers," U. S. Department ot Agriculture, 



JJiv. of Veg. 1'hys. and Path., Bulletin 25, 1900. 



