FORESTRY IN FRANCE. BOT 
Pl. IX. After the main features, such as the streams, ridges, and 
roads, have been laid down on the map, the temporary plots, and 
the descriptions of them, are made as before. The forest might, in 
the present case, be divided into three sections, the upper of which 
being on the crest of the hill, is required to be kept as dense as 
possible, and will not be dealt with in the working plan, as dead or 
dying trees alone will be removed from it. Suppose that the annual 
yield of the central section, which is 150 acres in extent, has been 
fixed, with reference to the estimated rate of growth and degree of 
completeness of the stock, at 50 cubic feet per acre, and that trees 
of marketable girth within it contain on an average 100 cubic feet 
of timber, it follows that the number of such trees which may be 
- «150 by 50 : 
removed annually from the section is “[ =75. Theoretically 
this number should be taken one here and one there over the whole 
area ; but this would be very inconvenient, so the forest is divided 
into twelve or any other convenient number of equal or nearly 
equal blocks, from each of which, in succession, the entire number 
of trees is to be cut ; after taking windfalls, the choice falls on the 
ripest trees, those which are dead or dying being selected first. The 
section below the road is in another zone of vegetation ; it is 100 
acres in extent, and its annual yield is calculated at the rate of 60 
cubic feet per acre. Suppose, then, that the trees of marketable 
girth contain on an average 110 cubic feet of timber, the number 
of such trees to be cut annually is ae 54, The section will 
then be divided into blocks,—in the instance illustrated by the map 
the number is ten,—from each of which in succession the entire 
number of trees is taken. In this manner each zone of altitude 
may be dealt with on its own merits, while, at the same time, the 
annual fellings, being localised, are easy to supervise, and the wood 
can be disposed of more readily and more profitably than if the 
trees had been felled here and there over the entire area. The 
working plan for a forest under conversion would, of course, differ 
from any of the above; but this somewhat complicated question 
will not be dealt with here. It is only by an arrangement similar 
to one of those above briefly sketched, that a permanent annual 
yield of a particular class of produce can be assured, and that the 
forest ean be secured against the risk of gradual extinction. 
A special branch of the Forest Department is charged with the 
preparation of working plans, which are not made by the local 
officers, except in the case of small forests, the plans for which they 
