METHOD OF THINNINGS. . 41 



From the first periodical thinning until the trees 

 have attained their utmost height, the thinnings 

 should be moderate for nearly every species, that is 

 to say, while gradually allowing to each crown the 

 necessary space for its regular development, the leaf- 

 canopy must be opened out but slightly every time ; 

 even after this stage, while the growth is telling on 

 the diameter, this will still hold good for the beech, 

 the silver and spruce firs, &c., all of which species 

 grow by nature thickly together and the timber of 

 which has nothing to gain, and, in the case of conifers 

 may even lose, in quality, by a rapid growth. 



But in the case of trees whose quality and density 

 are proportional to the rapidity of growth, especially 

 the oak, it becomes advisable to open out the leaf- 

 canopy freely, when the requisite height of bole has 

 been attained. In this case it is necessary to thin 

 heavily. 



The last thinning, which precedes the regeneration 

 cuttings, is generally severe, whatever be the kind of 

 tree operated upon. But then it is no longer a sim- 

 ple improvement cutting ; it is rather a real primary 

 cutting. This is technically termed a very close 

 primary cutting. Its effect is to open out the crop 

 while still preserving the continuous leaf-canopy, 

 and it differs from a severe thinning in requiring the 

 removal of low shrubby growth from the soil. The 

 advantages of working thus are all the greater, as 

 regeneration is longer and harder to obtain accord- 

 ing to local conditions. 



In mixed crops, a thinning may always have the 

 character of a cleaning. In a mixture of oak and 



