110 ELEMENTARY FORESTRY. 
only to burst open again the next winter. This alternate burst- 
ing open and growing over may continue for many years, until 
very conspicuous and peculiar wounds are formed. In such 
cracks insects and rot-producing fungi find favorable lodging 
places, and as a result trees are seriously injured, and are liable 
to decay in the trunk. ‘There are no practical remedies for such 
injuries. 
Wind. Jnjurics from wind are common where thinning is 
done to a great extent at one time about shallow rooted trees, 
such as Spruce growing on moist soil. 
These injuries can be avoided only by 
thinning gradually. In many such 
cases, on timber lands, thinning is im- 
practicable, and it is then best to cut all 
the merchantable timber, for if left it is 
sure to be blown down. 
On our prairies, where the soil is 
light and easily moved by the wind, it 
is not uncommon to have young seed- 
ling trees seriously injured by the blow- 
ing away of the soil around the roots, 
which often leaves them uncovered for 
three or more inches. This injury 
usually takes place in the spring, and 
may be almost entirely prevented by 
seeding the land to oats about the mid- 
dle of July, at the time of the last 
cultivation. Sown at this season the 
oats form a good sod that serves to 
hold the soil in place until spring, 
when it is easily broken up by cultiva- 
tion, but even then the roots prevent 
the blowing away of the soil. Occa- 
sional strips of grass are also a_pre- 
ventive of this injury, or mulching may 
be resorted to. 
Snow Crust. ‘The settling of a 
snow crust that has formed on the top 
MS of deep snow drifts may cause injury to 
young trees by stripping off their 
fuente 26, Old Frost peanolies aid breaking the stems. It 
Cracks in Sugar Maple. Pranc 1 8 
