802 TENDIXr, OF OPEN WOODS FOR LARGE TIMBER. 



The pnx'cdure differs coiisideral)!}' according to species and 

 the ol)jects of management. To meet the special requirements 

 of each case a considerahle numher of modifications have been 

 ehiborated. Some of these commence with tlie isohition in 

 early growth, while others during the greater part of the 

 rotation follow the system described in the last chapter, and 

 reserve to its latter part the isolation of the more valuable 

 trees. 



Although the treatment has been recommended for almost 

 all species, it is eas\' to perceive that thinly crowned species, 

 which are generally light demanding, are better adapted for 

 the method than those with a dense crown, as the underwood 

 has a better chance of thriving under the former, and doing 

 justice to the task which it is called upon to perform. In 

 Britain the oak, larch, and Scotch pine have, in a rough way, 

 been treated according to this method for a long time past. 

 On the Continent the treatment has been elaborated in 

 comparatively recent times. 



2. I'riiicijial Foniis <ij' TrcutiiiiiiL 

 Tliese may be enumerated as follows: — 



t>. Isdhttidii of a fi'ir Srlirlnl Tiers, irilhoiif C inlcnroinl. 



A limited number of selected trees are placed in a free 

 position, by removing all surrounding trees which threaten to 

 interfere with them. The system should be applied only in 

 case the nuiin part of the wood consists of a species with full 

 crowns, and where the selected trees are of (juicker height 

 growth than the rest. 



To avoid loss of height growth and the retention of low side 

 bi-iuiches, the operation sliould not be commenced until 

 towards the end of the period of principal height growth. 



The treatment is specially adapted to mixed woods of beech 

 and light deniaiidiiig broad leaved s[)ecies, such as oak. ash, 

 and elm. 



