20 BULLETIN 153, U. S. DEPARTMENT OF AGRICULTURE. 
Snow and frost may also cause considerable damage; the former 
weighs down and breaks off branches and leaders; the latter, when 
occurring late in spring or early In autumn, may kill the succulent 
wood. Damage from snow is less likely with hardwood trees than 
with conifers, because the bare branches of the former do not permit 
as much of it to accumulate. Frost damage may be partly avoided 
by planting hardy species or by utilizing sites on north, northeast, or 
northwest slopes, where growth begins comparatively late in spring 
and stops early im the fall. Low sites on which there is poor circu- 
lation of air should be avoided. 
GRAZING ANIMALS. 
Sheep, cattle, or horses should never be allowed in a young planta- 
tion. They browse upon leaves and tender shoots and trample the 
trees, which become crooked, branchy, and dwarfed. If pasturing is 
continued the trees will eventually be killed. Bulletin 200 of the 
Wooster (Ohio) Agricultural Experiment Station, sums up, for Ohio, 
the damage from this source: 
The acres of young forest which have been needlessly destroyed within the State 
foot up into the millions. Their value, had they been protected from live stock, would 
to-day amount to double the sum which has been realized from the pasture. This is 
demonstrable, for the investigations of the experiment station have shown that the 
value of young forest-tree growth exceeds the value of woodland pasture more than 
two toone. There isno such thing as profitable woodland pasture. The combination 
of grass and ferest is incompatible. Cattle derive but little, if any, benefit from brows- 
ing or from the shaded innutritious grasses, but they do damage the trees. The losses 
from this practice are largér to-day than ever before because of the constantly increas- 
ing value of the trees which are destroyed. 
In a plantation of green ash at Kanawha, lowa, trees which had 
been protected from cattle were from 10 to 17 feet high, while others 
of the same age which had been browsed by cattle were for the most 
part only 4 feet high. Jn a 5-year-old plantation of black locust in 
Michigan, grazed by both sheep and cattle, ungrazed trees had 
reached an average height of from 8 to 14 feet, when those browsed 
by the stock were only from 2 to 3 feet high. In a 10-year-old plan- 
tation of black walnut in Indiana, grazed by cattle, 25 per cent of the 
living trees had been broken by stock, and averaged from 5 to 6 feet 
in height; the unbroken trees were from 19 to 25 feet high. The 
owner stated that the trees were pretty well tramped out at one time, | 
which accounts for the fact that of the trees originally planted 78 per 
cent are now Missing. 
In older plantations the damage done by stock consists largely m 
packing of the soil. As a result of the stock running at large, the 
humus is destroyed and the roots of the trees exposed and perhaps 
wounded, while the soil becomes impervious to water. The stand, of 
course, suffers accordingly. Moreover, fungi may enter the trees 
through wounds around the base or in the roots. 
