INVESTIGATIONS OF THE ROTTING OF SLASH IN ARKANSAS. 5 
BRUSH WHEN PILED. 
White-oak brush piles were examined, ranging from 1 to 5 years 
in age. During the first year after the trees were cut but little evi- 
dence of rot could be seen except a discoloration of the sapwood. By 
the end of the second or third year all of the leaves had fallen from 
the twigs which were exposed to the sun's rays, and the brush at the 
tops and sides of the piles where exposed to the sunlight had rotted 
to some extent, while the slash in the middle of the piles not in actual 
contact with the ground and yet protected from the sunlight was 
rotted but slightty, if at all. The twigs and small branches at the 
bottoms of the piles were more or less rotted by certain other fungi 
(called "ground" fungi in this bulletin), which apparently entered 
these branches from the soil. These ground fungi seem to rot the 
brush more rapidly and more thoroughly than the regular slash-; 
rotting fungi. 
Usually there is but little evidence of rot in the center of the piles 
during the first four years after piling. However, around the edges 
and through crevices in the top the sunlight sometimes penetrates 
sufficiently to permit slight fungous growth. Nevertheless, there is a 
marked difference between the rotting of the brush in the center of 
the piles not adjacent to the ground and that at the top and bottom 
of the pile. 
By the end of five years the top and bottom of the piles have rotted 
to a considerable extent, while the brush in the center of the piles, 
where it had become more or less exposed to the sun's rays, was 
beginning to rot. 
For the brush in the center of the piles to rot completely it appar- 
ently (1) must be brought within range of the soil moisture by the 
rotting of the brush below it and by the settling of the pile, or (2) 
the upper portion must disintegrate sufficiently for the sun's rays to 
reach the center of the pile. Undoubtedly, both conditions finally 
develop and aid in the rotting of the brush which was originally in 
the center of the piles. 
In a white-oak brush pile the layer of brush at the bottom would 
be the only one even in partial contact with the soil, while the 
remainder of the pile would be held from the soil by this first layer 
and therefore could not receive any benefit from the soil moisture. 
Neither are the piles dense or compact enough to raise the moisture 
content of the air around the brush in the piles sufficiently to encour- 
age the growth of the ground fungi in branches not in actual contact 
with the soil. On the other hand, the brush not in contact with the 
soil in the piles and yet sheltered from sunlight is deprived of the 
activity of the fungi which normally rot slash in the open ; that is, 
slash when left as it falls in the tree tops. 
