64 THE BOOK OF FORESTRY 
forty-five years would be none too long to produce 
timber of this size. Such cultural methods are 
worth while and are being adopted by progressive land- 
owners in this country. Among the methods of man- 
aging the forest and increasing its growth ‘‘improve- 
ment cuttings’’ ranks as one of the most important. 
By improvement cuttings, we mean removal of timber 
from immature stands for the purpose of hastening 
growth, reducing competition, and improving the mix- 
ture of trees in the forest. In some eases cuttings may 
be made in stands of small sprouts where the material 
is too small to pay for the cost of removal, but such 
cuttings, or cleanings, as they are called, are hardly 
practicable in the United States, on account of the 
high labor cost and the comparatively low value re- 
ceived for timber. In fact cleanings may cost from one 
dollar and fifty cents to three dollars per acre. 
Under the average conditions in this country it is 
advisable to allow a young forest to grow untouched 
until the trees are large enough to pay for the cost of 
removal. Then a thinning can be made which will re- 
move competing trees, defective and diseased specimens 
and “weed trees,” as the species of no commercial value 
are called. The trees of desirable species remaining 
upon the ground receive more light, more food and 
moisture and consequently commence to grow much 
faster. For instance, in our Eastern forests such trees 
as ash, basswood, tulip, poplar, red oak, etc., are gen- 
erally favored over the slower-growing and less desirable 
beech, maple, black oak, horn beam (forest weeds), ete. 
Rapid-growing conifers like pine and spruce are to be 
preferred to the slower-growing and less valuable species, 
like hemlock and white cedar, although in each case the 
kind of soil must control the species to be favored. 
