INVESTIGATIONS OF THE ROTTING OF SLASH IN ARKANSAS. 9 



bottom of the piles must disintegrate sufficiently to expose the center 

 of the pile either to the sunlight or to the moisture of the soil. This 

 would probably add from three to five years at least to the length of 

 time it would take to rot the slash in the brush pile as compared to 

 that required if pulled or scattered. 



BRUSH WHEN SCATTERED. 



Practically the same conditions hold for shortleaf-pine slash when 

 lopped and scattered as for oak slash; that is, the same groups of 

 fungi which attack the pulled pine slash will attack the slash when 

 scattered on the ground unless it be covered with leaf debris. Ground 

 fungi will also attack that portion of the brush immediately in con- 

 tact with the soil, provided the area under consideration is not too 

 dry, like the south and southeast slopes of steep hillsides. In such 

 locations no evidence was found of ground fungi attacking the scat- 

 tered brush, or even the brush in the bottom of the piles. This means 

 that the pine brush when lopped and scattered will rot much quicker 

 than when it is piled, and on some sites slightly quicker than when 

 left attached to the tops or pulled. 



THE GROWTH OF WOOD-ROTTING FUNGI. 



There is this physical factor to be kept in mind when considering 

 the rotting of slash, viz, that the quantity of water which a limb or 

 branch obtains is practically limited to the precipitation which that 

 limb or branch receives and is able to absorb through its bark into the 

 sapwood and that, so far as the amount of moisture in the wood itself 

 is concerned, the humidity of the air around the branch would not 

 be an important factor, since conditions would have to be very unique 

 which would enable a branch covered with bark to absorb from the 

 surrounding air a sufficient quantity of water to make any appreci- 

 able difference in the water content of the branch or limb. This 

 would mean that the distance the branch was from the ground, 

 whether 1 foot or 5 feet, would make but little difference in the rela- 

 tive supply of moisture obtainable from the atmosphere which the 

 wood-rotting fungi in the branch could utilize. It might, however, 

 determine to a slight extent the amount of moisture which the limbs 

 could lose, especially in the bottoms of the piles. In regions of heavy 

 dews the brush lying within 1 or 2 feet of the ground might obtain 

 more moisture than brush farther from the ground. 



This indicates that the slash would have to be practically in con- 

 tact with the soil to gain any appreciable quantity of moisture other 

 than that obtained from precipitation, and from the very nature of 

 the oak brush only small portions of any given limb would be thus 

 placed. 



