6 BULLETIN 496, U. S. DEPARTMENT OF AGRICULTURE. 



Since piles more than five years old were not found, the writer 

 can not state positively the length of time necessary for a medium- 

 sized compact brush pile of white oak to rot completely. Apparently 

 it would take from three to six years longer than if the brush were 

 either pulled or scattered. However, if the piles are very small, the 

 brush will rot with about the same rapidity as when the tops are 

 left unlopped, since the sunlight can then penetrate to the bottom. 



SPOEOPHOEE DEVELOPMENT ON PILED BRUSH. 



The difference between the development of sporophores at the top, 

 middle, and bottom of brush piles is very marked. Practically every 

 twig and limb at the top of the pile bore the characteristic sporo- 

 phores of Stereum rameale, S. umbrinum, and S. versi forme on the 

 rotting limbs, while no sporophores whatever were found on branches 

 in the center of brush piles which were large and compact enough to 

 'exclude the sunlight. Very rarely were any sporophores of wood- 

 rotting fungi found on the material at the bottom of the piles, 

 although sterile mycelium was frequently present on the brush so 

 situated. It was therefore difficult to determine what fungi were con- 

 cerned in the rotting of the brush in the bottom of the piles. How- 

 ever, sporophores were found of Merulius tremellosus, Peniphora 

 flavido-alba, Odontia sp., Poria pulcliella, and two unidentified 

 species of Poria. r 



BRUSH WHEN SCATTERED. 



When the brush is lopped and scattered it rots much more quickly 

 than when piled, and in some localities somewhat more quickly than 

 when left attached to the tops. On the areas examined the gain in 

 the rotting of brush when scattered compared to that when pulled 

 was usually about one year. 



When white-oak brush is scattered, only small portions of the limbs 

 are actually in contact with the soil. The same fungi, therefore, that 

 rot the unlopped brush will also rot most of the scattered brush, and 

 with about the same rapidity. 



Brush lying on the ground sometimes absorbs from the soil suffi- 

 cient moisture for the growth of ground fungi in those portions of 

 the limbs which are in actual contact with the soil. On many of the 

 areas examined the additional moisture obtained from the soil by the 

 scattered brush was not sufficient to cause the 'ground fungi to attack 

 the prostrate limbs. 



The influence of soil moisture on the branches lying on the ground 

 usually does not extend more than 4 to 6 inches from the point where 

 the limb is in contact with the soil. This means that the benefit to be 

 derived from the ground fungi rotting a branch is limited to that por- 

 tion directly in contact with the soil. On account of the small quan- 



