16 BULLETIN 580, U. S. DEPARTMENT OF AGRICULTURE. 
Counts were made on 17 plots located in situations subject to this 
kind of injury. Of 165 trees above 3 feet in height, and so of a size 
subject to severe damage by rubbing, 36 were seriously injured. Fif- 
teen were so badly rubbed that they would become worthless if the 
rubbing continued, and 2 were moderately rubbed. Thus 22 per 
cent of the trees subject to this class of damage had been severely in- 
jured, and 9 per cent were being subjected to severe damage. In all, 
a total of 31 per cent would in time be killed. This indicates a seri- 
ous condition over certain parts of the yellow-pine type. ‘The sites 
on which such damage is most likely to occur support the best quality 
of timber. 
Damage along sheep driveways.—In the southern part of the Forest 
the only places where pine reproduction seems to be injured are 
around watering places, near the lower boundary of the yellow-pine 
type where reproduction is scattered, and along the Mud Tank sheep 
driveway. This driveway, with an average depth of 1 mile, extends 
about 30 miles through the yellow-pine type. About 75,000 sheep 
are driven over it each year. Besides its use as a driveway, the strip 
is included in sheep and cattle allotments, and would be fairly well 
grazed by stock throughout the season without the additional use by 
transient stock. The first few bands find sufficient feed, but before 
the total number have crossed the feed is so short that sheep are 
forced to eat whatever growth is available, including a great deal of ~ 
yellow-pine reproduction. The damage caused in this way is so 
severe that the boundaries of the driveway can readily be traced by 
the line of severe damage. Conditions on this trail are typical of a 
number of trails in Arizona and New Mexico. Good management re- 
quires that this damage be reduced to the minimum. 
Around watering places and ranches where stock are allowed to 
congregate it is very common to find a majority of the reproduction 
badly deformed and stunted, as a result of browsing and rubbing. 
EFFECTS OF GRAZING INJURIES UPON WESTERN YELLOW-PINE 
REPRODUCTION. 
ESTABLISHMENT OF REPRODUCTION. 
INJURIOUS EFFECTS. 
Abundant reproduction is often found in pastures, while just out- 
side, with no apparent change in natural conditions, it is relatively 
scarce. In all such cases observed the outside range had been subject 
to severe grazing by all classes of stock for a number of years after 
the pasture had been constructed. A comparison of the ages of 
reproduction within and those adjacent to the pastures indicates that 
the effect of severe grazing outside has been not only to prevent the 
establishment of reproduction, but also to kill many of the trees 
already established at the time the fences were built, -This conclu- 
