HOW THE FOREST IS GUARDED 105 
vegetable, as man does to the animal, kingdom; the 
highest, the most perfect of its type. 
Wind, Ice and Snow.—Of wind, ice, and frost much 
could be said. Shallow-rooted species like spruce and 
lodgepole pine of the Rockies are very subject to wind 
throw. Snow or sleet storms may cause great damage 
especially in young stands by bending and breaking 
the leaders and branches, thus ruining the shape of the 
tree or at least making fungus infection through broken 
limbs quite probable. During frosty nights trees may 
crack open owing to unequal contraction of wood and 
bark and these ‘‘frost ribs’’ reduce the value of the 
lumber. 
Wind, while a friend of the forest and a great help 
in assisting trees to spread to and hold new areas of 
land, nevertheless can inflict heavy damage upon the 
forest communities. Shallow-rooted species like spruce 
or the lodgepole pine are subject to severe damage 
from windthrow and only by careful cuttings in such 
forests can heavy losses be avoided. In the Southern 
pine forests over which terrific tornadoes from the Gulf 
of Mexico sweep from time to time, the loss 1s quite 
heavy, especially if a forest of long-leaf pine has been 
‘‘boxed’’ for turpentine (see Chapter XI), for this box- 
ing greatly weakens the trunk. Even though the trees 
are not actually blown down, heavy gales may inflict 
considerable damage, for if the bark of a tree, which 
serves aS a protective covering like our own skin, is 
broken by a torn limb, the spores of some tree disease 
may enter and ultimately cause the death of the tree. 
The method of preventing wind damage is easy to 
state but often hard to secure. It consists in cutting 
very lightly in dangerous situations or in forests subject 
to windthrow. The German foresters sometimes plant 
