PA.RT IV.] 
PRUNING AND THINNING. 
213 
tions, a tree cannot have too many branches, 
as the returning sap of each contributes to the 
growth in girthing of all that part of the stem 
which is below it, and to the growth of the root 
both in length and girthing. But pruning, 
like thinning a plantation, cannot be too gradual. 
It should be annual. 
A well-placed but over-large branch should 
be curtailed where it turns up, or where it forks, 
or at the foot of a shoot. It is bad pruning 
to leave a dead stump with no growth beyond 
it, whose descending sap shall deposit over the 
scar. 
In timber-woods, and in plantations, the trees 
should stand close enough to discourage the 
growth of many side-boughs, or of any large 
ones. As the side-boughs are gradually and 
annually overgrown, and before they are actu¬ 
ally killed, they should be removed with a com¬ 
mon saw, set wide for the purpose ; and the 
axe and cross-cut saw should gradually and 
annually thin the plants out to greater distances 
from each other. Timber may thus be reared 
without a single disunited knot; and if we sup¬ 
pose the side-boughs to be taken off each, where 
the stem is eighteen inches in girth, without a 
symptom even of a cross-grain, at a greater 
p 3 
