Methode du Controle 45 



tree class, 30 per cent, in the medium class, 20 per cent, in the 

 young class. In the following cases, it may be advantageous to 

 change these proportions ; for example, to increase the proportion 

 of older trees if the soil needs protection, or to lessen the older 

 classes according to species and exposure, if more sunlight is 

 needed for the appearance of natural reproduction. 



3. As regards the rate of growth to expect, the beginners of the 

 method counted on obtaining a rate identical with the ordinary 

 agricultural rate, i. e., to reahze 3 per cent on the growing stock. 



We must be careful not to fix the cut too high, so as not to 

 infringe on the growing stock, and must know why and where to 

 apportion the cut. 



This method is much less a method of absolutely mathematical 

 results, applicable to all forests, than a simple process allowing 

 the finding of all necessary information in the forest. 



Advantages of the Method are: 1. (a) An exact account of 

 what is done can be kept, and of the effect produced by the oper- 

 ations carried on, so as to modify future proceedings to suit the 

 object in view, (b) The short period between surveys allows 

 checking, and lessens the chance of overestimating. 



2. It separate? growing stock and increment completely (as 

 money invested and interest on it) ; so a system of really com- 

 mercial books can be kept. The money value secured on the 

 basis of reconnaissance, the cut or yield by calculating increment. 

 All cutting exceeding the allowed cut is considered as a loan taken 

 from the forest. The forester knows exactly how the forest 

 stands and can cut heavily or lightly, or plant as he sees fit. 



3. By use of the per cent, basis, for cut, we rid ourselves of 

 the theoretical and hypothetical idea of an "Age of Exploitability," 

 corresponding for the whole stand, and of notions too general and 

 difficult of application, of fixing the probable increment by a "fac- 

 tor of fertility" necessarily inexact. The method relies on actual 

 data from the forest so there is a minimum chance for error in 

 calculating. 



4. All trees cut for any reason whatever, are considered and 

 figured in the income from the forest. 



5. Though the method uses a diameter limit, this does not pre- 

 vent the practice of good silviculture. It allows the cut to be 

 made in all size classes if that is the better way. 



