330 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 
It is now neeessary to give some indication of the Cost of 
Management of the plantation. This is difficult to do with any 
degree of accuracy. If there is only one area to be managed, and 
all of the same age, the expense will be greater than if there are 
several areas of different ages. Taking the area of 640 acres, and 
ealculating from the average of similar plantations, the whole cost of 
management and maintenance may be estimated at 12s. per acre, 
or in all about £360. The thinning at about twenty years of age 
should pay itself, if the plantation is situated in a good locality. 
This is not the case as a general rule, but what the forester and the 
owner have to bear in mind, irrespective of profit from thinnings, 
is to thin in such a manner as will prevent injury from suffocation, 
and allow free circulation of air and light to the soil about the 
roots, so as to strengthen the latter against storms, and the 
possibility of the trees being upset by them. This done in proper 
time, the success of the plantation is assured. 
