38 NATURAL REPRODUCTION OF FORESTS. 
an economic point of view. This may occur at any age ranging 
from 80 to 120 years. But it will depend much upon local 
circumstances, as the ratio of growth and the vigour of the 
trees will be in proportion to the conditions of the climate, soil, 
elevation, aspect, and exposure, 
It is presumed that the forest is fairly drained and securely 
fenced. The first operation, then, is to begin a series of thinnings 
at intervals over the entire forest, adopting at the outset a 
systematic method of selection of reserves at each felling of 
timber. These thinnings should extend over a considerable 
period of years. I would urge that in all cases the first cutting 
be carried out with great caution; and this should be speci- 
ally attended to when the crop upon the ground is dense, as 
all the roots will be weak and superficial in proportion to the 
density. The trees, therefore, cannot have such a hold in the 
soil, and will be liable to suffer injury from boisterous winds. To 
guard against this, a thick sheltering belt ought to be left all 
round the outside of the forest. By so doing it will serve a two- 
fold purpose of some importance. First, to act as a barrier 
against the wind ; and second, to give shelter to the young seed- 
lings. Should the forest be so extensive that it is impossible to 
spread the periodical thinnings over the entire area, it will be 
necessary to adopt another method, viz. to have it done in 
sections or sub-sections as may be found most suitable. In com- 
mencing to fell the timber within the belt that is left for shelter, 
begin at the side which is most exposed to the breeze. By so 
doing the older seedlings will help to shelter the younger from 
the blast. At each thinning it is essential to select the worst 
trees for cutting first, such as those that are stunted in growth 
and deformed ; all that show any signs of decay, as resin bursts, 
foliage changing to a yellowish green, annual growths arrested or 
diminishing, and those which bear great numbers of cones of a 
diminutive size ; these being all indications of approaching decay. 
At each felling, all the loppings of branches and brushwood 
should be gathered into heaps and carted outside the wood, with- 
out delay, to any open spot where they can be burned, so as 
not to injure the foliage of the reserve trees, or any seed that 
may be germinating near the surface of the ground. Should the 
surface of the soil be covered with a tough herbage of grass or 
heath, it will be necessary to go over it, after the brushwood and 
rubbish is removed, and take off large sods, say 18 to 24 inches in 
