A DISEASE OF PINES CAUSED BY CRONARTITJM PYEIFOEME. 15 
The largest infected tree found was 12 feet high and 3 inches in diameter at breast 
height, approximately 22 years old, with the infection occurring 5 feet from the ground. 
In another area here 10 saplings killed by the fungus, with only one living uninfected 
tree, were found. 
One diseased area of Pinus ponderosa at Mills Ranch on the north 
slope of Goosenest Mountain in the Klamath National Forest was 
described by Boyce, which contained at least a hundred acres. The 
largest tree diseased by the fungus in this area was 8 inches in diame- 
ter at breast height. Spindle-shaped swellings were common, but 
more especially on the younger, smaller trees. The girdling effect 
and death of the host tree in the parts above the point of infection 
were very much in evidence in this area. Small trees apparently 
were girdled and killed much sooner than older trees. Wounds caused 
by some gnawing animal, presumably the porcupine, were common 
on trees in areas where the fungous disease occurred. In one of the 
diseased portions of the forest a sample plat was established by 
Boyce and a count of the healthy, infected, dead, and dying trees 
of Pinus ponderosa was made. The result was as follows: Out of 314 
trees in the plat, 153 (48.7 per cent) were apparently healthy, 52 
(16.5 per cent) were plainly diseased by the fungus, 3 (0.9 per cent) 
were dying, and 106 (33.7 per cent) were dead from the effects of the 
fungus. In the words of the report: 
Over 50 per cent of the total number of trees of the sample plat had been infected, 
and nearly two-thirds of the total number infected had already been killed. There is, 
of course, a possibility that the death of some of these might have resulted from other 
causes, but only those trees were included which I was certain in my mind had been 
killed by the fungus. 
Boyce's data corroborate those taken by the senior writer both in 
Pennsylvania and South Dakota. 
Reporting concerning an area of diseased Pinus ponderosa along 
Browns Creek in Trinity National Forest, Boyce says: 
There were many dead trees, undoubtedly killed by the fungus, with spindle-shaped 
swellings on the main stems. On living infected trees the secia were sporulating 
(June 27, 1914), but not very abundantly, not to be compared with the sporulation 
found at Rocky Gulch on May 20. One infected sapling was found in which the 
major portion of the bark had been destroyed either by wood rats or porcupines. 
Where the trunk is not girdled, cankers or catfaces are occasionally 
formed by the death of a portion of the cambium. In such cases 
the continued presence of the fungus in the live tissues beyond the 
dead area stimulates their growth, and the fungus may fruit a number 
of times before the tree is killed. Catfaces on the lodgepole pine 
(Pinus contorta) and on the western yellow pine (Pinus ponderosa) , 
however, are more commonly produced by another species of rust, 
Peridermium Tiarknessii. 
Peridermium pyriforme, when it infects the trunk of a pine tree, 
may spread from the trunk to such limbs as spring from a point near 
