112 
Journal of Agricultural Research 
Vol. I, No. 2 
Table I .—Data on jive types of butt-rots found in white oak (Quercus alba L.)— Contd. 
SUMMARY. 
Average— 
Total 
Name of rot. 
Cause. 
Diameter 
of stump. 
Diameter 
of rot in 
stump. 
Height 
of rot in 
butt. 
Age oi rot. 
number 
of trees 
infected. 
Hollow-producing 
Hydnum erinaceus 
Inches . 
26. O 
Inches. 
12 . 6 
Feet. 
3-9 
Years. 
648 
rot. 
Pocketed or piped 
Polyporus pilotae.. 
25. 6 
I 3 - 7 
3*9 
156 
408 
rot. 
Brown, checked 
Polyporus sulphu- 
25-8 
13. 6 
3 -o 
270 
rot. 
String and ray rot.. 
reus. 
Polyporus berke- 
28. O 
19. 0 
3 - 5 
190 
57 
Straw-colored rot.. 
leyi. 
Polyporus frondo- 
27. O 
14. O 
2 - 3 
12 
sus. 
In the above summary are given certain data for each of the most 
important butt-rotting fungi in white oaks, and from them some 
idea can be obtained as to the amount of damage done by these heart- 
rotting fungi in the virgin timber of the Ozark National Forest. All of 
the rots listed in the table are also found in black oak (<Quercus velutina 
Lam.), as well as in white oak, but on account of the limited number of 
trees of this species examined no data are now given for it. All height 
and diameter measurements given in this article, unless otherwise stated, 
were taken from the tops of stumps 12 inches high. 
In determining the age of the rot only trees were used in which the 
fungus had undoubtedly entered at an old fire scar long since healed over. 
The annual rings of wood were counted from the point where the callus had 
completely closed the wound, so that the heart-rotting fungus must have 
entered before the wound was covered. Therefore, the figures given here 
represent the minimum age for each infection. The rot might have 
entered sooner and therefore be older, but it could not have entered 
later and therefore be younger, as the callus had closed the wound. No 
stumps with open wounds of any kind were used in estimating the age 
of the rot. 
The writer realizes that this method of determining the length of time 
the fungus has been in a tree is open to the following criticism: 
(1) The fungus might have entered underground through injuries 
which reached to the heartwood of the root and thence moved upward 
into the bole of the tree; (2) the wound made by the fire may have healed 
above ground, but not below on the stool and roots of the tree, thus 
