24 



on fallen trees for several years in succession, possibly omitting a j^ear 

 now and then. As a rule but one set of sporophores is found on one 

 tree. As has already been said, young trees are subject to the attacks 

 of this fungus as well as older ones, although the latter are probably 

 more so, because the points of infection are so much more numerous. 

 Nothing is known as yet of the manner in which the fungus enters 

 the tree, nor of the rate at which it grows within a tree after having 

 obtained a foothold. 



TREES ATTACKED. 



Polyporus schweinitzii was found growing on the roots of the White 

 and Red Spruces, Balsam Fir, and Arbor Vitce. It is likewise com- 

 mon on the White Pine {Pinus strohus). 



METHODS OF COMBATING THIS FUNGUS. 



Because of its destructiveness Polyporus schweinitzii is perhaps the 

 most to be feared, where living trees are concerned. As it spreads 

 through the soil it is difficult to detect, and still more difficult to com- 

 bat. In the European forests a deep trench is dug around an infected 

 tree or group of trees; this trench prevents the spread of the mycelium 

 through the ground to neighboring trees. Such a method can not be 

 recommended for American forest tree conditions, at least not for the 

 present. If a group of infected trees is met wnth in the forest while 

 lumbering it may prove advantageous to cut all trees in the vicinity of 

 the diseased ones. Some of these may produce a hollow sound when 

 hit near the base, an indication that the decay has started. It may not 

 have gone up into the tree very far as yet, so that one or more logs 

 can be obtained from the top. It will not be profitable to hunt out 

 diseased trees as is done in European forests. There is as j^et no 

 evidence that the fungus can infect a tree above ground, consequently 

 it need not be feared in burned-over regions, or such as have been 

 attacked by bark beetles. 



POIiYPORUS PINICOIiA (Swartz) Fr. 



OCCURRENCE. 



This fungus occurs widely distributed over the world, growing on 

 conifers and occasionall}^ on Birches and other deciduous trees. In 

 the New England forests it is one of the most frequent fungi found 

 on living or more often on dead trees of Spruce, Pine, Fir, and Hem- 

 lock. From three to ten of its bright colored sporophores may grow 

 on a single log for several, varying from three to five, years. At the 

 end of that time the mycelium has used up the available food supply 

 in the loo' and dies. 



The sporophores grow on living trees, but these alwa5's appear 

 weakened or sickly. No vigorous, healthy trees were found on which 

 this fungus flourished. It is essentialh^ a wound parasite, entering 



