ON THINNING PLANTATIONS. 91 
fully half the number of plants inserted per acre should be 
removed by the time that the most valuable portion is twenty 
feet high. When they attain the height of thirty feet, they 
should stand on an average fully seven feet asunder, or about 
800 per acre. At the height of forty feet, which is generally 
that number of years’ growth, the trunks are formed to a 
considerable height; and at this stage of their progress it 
becomes necessary to furnish considerable space for the deve- 
lopment of the leaves of the trees which are to occupy the 
ground, in order that their trunks may possess a girth corre- 
sponding to their height ; therefore, generally speaking, they 
should stand from eleven to twelve feet asunder, or at the 
rate of from 300 to 350 trees per acre. 
An acre of ash, of elm, or of sycamore, at the age of forty 
years, in favourable soil, is generally found to contain from 
2000 to 3000 cubical feet of timber, and at the age of sixty 
about double that extent of measurable timber. This is 
exclusive of the thinnings, which are gradually removed up to 
this period ; which, even while plantations are young, form in 
many localities a source of great profit. The oak is found to 
be of rather slower growth from plants than the kinds last 
named, but its growth from stools of former trees is equal 
to these kinds) When oak and other trees, which spring 
from the root, are felled, it is of advantage to the succeeding 
growth to dress the surface of the stools into a convex form 
with an adze, so that they may not retain water. It is also 
necessary, in some parts, to remove a turf around the base of 
the old trunk, to admit the influence of the weather and pro- 
mote the young growths, the strongest of which, after having 
advanced a few feet in length, should be selected, and the others 
cut off. 
At all stages of a plantation, space should be gradually al- 
lowed, according to the growth of the trees, which, with some. 
sorts, in favourable situations, extends till the plantation is 
eighty years of age. But before this period, the trees, in 
plantations of hardwood, generally became irregular in size, 
and in their distances asunder, and the forest assumes the 
