338 PRINCIPLES OF BOTANY, ETC. 
The means to prevent wounds are obvious.— 
branches must be taken off with care; cattle ex- 
cluded from the neighbourhood of plantations ; 
trees brought up so, as not to require to be fastened 
to stakes; or, if necessary, to place three or four 
posts or stakes round each, and tie them up very 
gently. In violent storms it is indeed better to let 
them loose and leave them to themselves. Parasitic 
plants must be eradicated. But hurts by the bite, 
especially of smaller animals, and by hail, cannot 
always be prevented. 
§ 306. 
Fractura. Fractures are, when a stem or branches 
break, or are violently divided into many pieces. 
This arises from the violence of the wind; from a 
great abundance of fruit; heavy weights of incum- 
bent snow, and from lightening. It may be men- 
tioned as singular, that lightening runs along dif. 
ferent sorts of trees, almost always in a different 
manner. ‘The birch, (Betula a/bz), is in this re- 
spect different from all other trees, for in it the 
lightening never runs along the stem, but strikes 
only at the top, where it beats off the boughs almost 
ina circular direction. | 
A fracture, if not complicated, and on branches 
or young stems only, may be healed without dif- 
ficulty. ‘But if accompanied by contusion, or hap- 
pening in trunks of old gummy trees, recovery is 
impossible. 
In young trees and branches, even sometimes in 
old ones, when instantly discovered, fractures heal 
| easily, 
