182 College of Forestry 
The figures given above are striking indeed and show that 
Polyporus pargamenus, as judged by the frequency of its 
occurrence, is the only wood-destroying fungus to be reckoned 
with as yet in this particular locality. The rapidity of the 
infection and growth of this pernicious sap-rotting fungus is 
remarkably well demonstrated by the fact that, out of the 
total (364) standing hardwood trees upon this tract, 57 per 
cent bore fae es of Polyporus pargamenus within one 
year and three months after the area had been burned (Plate 
XXX). Here it may be mentioned that the weather was very 
oe during the two months prior to the survey so that prac- 
tically all the growth of the fungus may be credited to thir- 
Ree months. Of the trees bearing no sporophores of the 
fungus a few were charred so badly near the ground that the 
chances for infection were materially redueed, owing to the 
fact that little or no sapwood was left near the ground, a place 
which offers the optimum moisture conditions for the growth 
of wood-destroying fungi. Moreover, many of the trees 
which do not yet bear sporophores are undoubtedly infected 
by this sap-rot so that, before many more months elapse, a 
much higher percentage of the trees will bear sporophores. 
In addition new trees are constantly becoming infected. The 
white oak is the principal tree on this tract, ean of the 237 
white oak trees recorded, 69 per cent bore sporophores of 
Polyporus pargamenus. It is especially interesting to note 
that the smaller the trees were the less was the percentage 
containing sporophores of this sap-rot. Of the two-inch trees 
only 8 per cent bore sporophores, while of the three-inch trees 
40 per cent bore sporophores. From this point on as the 
diameters of the trees increased so did the percentage that 
bore sporophores, until 100 per cent was obtained for the 
nine, ten and eleven-inch trees which were the largest present 
upon this particular tract. No apparent relations between 
the diameter of the trees and the percentage bearing sporo- 
phores were evident in the other species but there were more 
white oak trees 6n the tract than of all the other species 
combined, so that for this species better and more uniform 
comparisons are to be expected. 
