120 
Journal of Agricultural Research 
Vol. I, No. a 
A comparison of the average height of this rot in the chestnut (5.4 feet) 
with its average height in the white oak (3.9 feet) shows that it extends 
higher up the bole in chestnut than it does in white oak. This difference 
is still further accentuated by the difference between the average diameter 
of the diseased chestnut trees (16.6 inches) and that of the diseased 
white oak (25.6 inches). The average age of the chestnut was probably 
not over 100 years, while that of the white oak was about 250 years. The 
very large and numerous vessels in the chestnut made it possible for the 
fungus to travel to greater heights in this wood in a given time than it 
could in the white oak, which is a much denser, slower growing wood. Of 
course, the amount of rainfall and other environmental factors would 
have to be taken into consideration when comparing the relative heights 
of this rot in the chestnut and oak. 
On the same area in New York where the chestnut mentioned above 
was studied, a record was made of 477 felled white oaks. Of this number 
only 4, or less than 1 per cent, had the piped rot so common in the 
chestnut. Its average height in these 4 trees was 3 feet, its average 
diameter was 8 inches, and the average diameter of the affected trees 
was 15 inches. This small percentage of infection was probably due to 
the fact that no fires had been allowed in these woods and therefore 
practically no opening into the heartwood of the trees was offered and 
to the further fact that the oaks did not originate from a coppice growth. 
On an area in Virginia which had been in timber for about 60 years the 
writer checked the stumps of 565 chestnut trees which had been recently 
cut. The majority of these trees originated from sprouts and had made 
a vigorous growth, the average age of the trees being about 50 years. Of 
the 565 chestnut trees only 18, or 3 per cent, had piped rot in the butts. 
Of this same area 201 white-oak stumps were also checked, of which 
number 13, or 6 per cent, had piped rot in the butts. This area was an 
old abandoned field which had been used as a pasture for many years 
and, so far as the writer could ascertain, had not been burned over in 
50 years. 
The rate of growth of the various rots in individual trees, as shown by 
the records made in the Ozarks, varies greatly. For instance, Polyporus 
sulphureus had been in one white oak 200 years and had made a growth 
in height of only 6 inches during that time, while the same fungus had 
been in another white oak for 50 years and had made a growth in height 
during that time of 3 feet. A similar wide range in growth is found for 
the rot produced by P. pilotae in white oak, where it was in one tree for 
280 years and had made a growth in height of only 6 inches, while in 
another white oak the same fungus had made a growth of 4 feet in only 
60 years. However, taking into consideration the average and maximum 
height of each of these rots and their average rate of growth in a tree, it 
is evident that they do not grow with any thing like the rapidity—at 
least in white oak—that might be expected. 
