16 BULLETIN 418, U. S. DEPARTMENT OF AGRICULTURE. 
Drought in combination with severe winter weather, particularly 
desiccating winds at a time when the ground is frozen after a dry 
autumn, sometimes does a good deal of damage to yellow pines in 
exposed situations. It occasionally happens that strips of timber 
adjoining the open country or in other particularly bleak and dry 
situations turn brown in the winter or early spring, all the old needles 
fall, and the trees are apparently winterkilled, but leaf out as 
usual after the growing season begins. To this form of injury the 
name "red-belt disease" has been given. Yellow pine does not 
suffer any more than its associates, and possibly less than Douglas 
fir. In the winter of 1909 the foliage on several thousands of acres 
in Morrow County (and to a less extent in Crook and Grant Counties) , 
chiefly on the north slopes adjoining the open country, turned brown, 
and the trees were apparently winterkilled, but recovered and seem 
to be in no way permanently injured. 
"Spike-top," or "stag-headedness," is commonly an indirect 
result of drought, and is usually an accompaniment of old age. In 
the virgin stands of yellow pine in Oregon, as elsewhere in this tree's 
range, there is a good deal of this defect, often from 10 to 15 per cent 
of the merchantable trees being affected. This is natural, since in 
the primeval forest such a large proportion of the trees are very old 
and past maturity. "Spike-top " considerably reduces a tree's value, 
both because the dead tip of the tree is worthless and because it is 
an entering place for decay. 
In certain regions, particularly on tne pumice soils of central 
Oregon, the soil in the forest "heaves" in the spring and autumn 
and lifts young seedlings out of the ground. This occurs here to 
such an extent as to make it difficult for reproduction (either natural 
or planted seedlings) to get a good start; some of the seedlings are 
killed outright, and many do not recover for years from the root 
injuries which they receive when young. 
Thunder storms are not infrequent in the Cascade and Blue Moun- 
tain regions of Oregon, and often yellow pines are struck by lightning. 
They are then scarred in such a way as to detract from their com- 
mercial value and occasionally are shattered or killed outright. It is 
not unusual for a group of half a dozen trees to be struck at the same 
time, so that the ground over half an acre is littered with chunks of 
bark and splinters. 
ANIMAL LIFE. 
Yellow pine suffers comparatively little injury from animals. 
Porcupines and other rodents gnaw the bark of saplings and small 
poles, and occasionally seriously damage or kill them. Sapsuckers 
and woodpeckers seem to confine their activities chiefly to dead and 
insect-infested trees Of this species and do no damage to the wood; 
in fact, they undoubtedly do a great deal of good by destroying 
harmful insects. 
