40 DISEASES OF DECIDUOUS FOREST TREES. 



the affected wood, and it differs very materially from a somewhat 

 similar disease caused by Stereum frustulosum, described later on, by 

 the fact that the white areas in the present disease are not sharply 

 defined, but appear as more or less regular white lines in the mass of 

 the wood. 



A disease very similar to the one just described for oaks has repeat- 

 edly been found by the senior writer in young chestnut trees, par- 

 ticularly in New York and New Jersey. (PL V, fig. 2.) In both the 

 chestnut and the oak the disease first manifests itself in the center 

 of the tree, extending outward until it reaches the sapwood. The 

 white masses, consisting of cellulose fibers, are at first confined 

 entirely to the spring wood of each annual ring. As the disease 

 progresses the changes brought about by the fungus spread into the 

 summer wood of each annual ring, and in advanced stages the entire 

 mass of wood fibers is affected. 



Trees of all ages having heartwood are affected with the piped-rot. 

 A number of instances were found of young chestnut trees growing 

 in a vigorous stand which were badly diseased when but from 25 to 

 30 } T ears old. In the case of the chestnut, the disease frequently 

 starts near the ground line, extending up into the trunk. This is 

 probably due to the fact that the fungus causing the disease obtains 

 entrance into the young chestnut through the old stump from which 

 so many young chestnut trees sprout in the form of coppice shoots. 

 In the oaks the disease is more frequently found originating in the» 

 top and extending downward into the trunk. 



There has been much discussion as to what fungus is responsible 

 for the piped-rot. In a great majority of cases no fruiting body of 

 any fungus can be found on diseased trees. In many localities in 

 Missouri and adjoining States, where the oaks are severely affected, 

 one frequently finds as many as 50 per cent of the young trees of the 

 second growth affected with this disease; but in spite of this fact not 

 a single fruiting body of any form has been found on the trees. 



The piped-rot is especially important in the chestnut. Preventive 

 measures with the chestnut involve coating the stumps of old trees 

 with some preservative, such as coal-tar creosote, so as to prevent the 

 entrance of mycelium into the old stump and thence into the young 

 trees growing from the stump. This coating should be applied very 

 soon after the tree is cut, because after the fungus has once obtained 

 a foothold in the stump it is almost impossible to get rid of it. This, 

 of course, will hold only where chestnut regeneration is brought about 

 by coppice formation. In the case of the oaks the preventive meas- 

 ures suggested for the false-tinder fungus will hold good. 



149 



