THINNING OF MIXED WOODS. 297 



individuals for the final crop. In mixed woods a third con- 

 sideration iDresents' itself in the preservation of a suitable 

 mixture without interfering with the maintenance of a sufficient 

 leaf canopy ; this often leads to deviations from the theory as 

 indicated above. 



In the case of mixed woods it may often be necessary to 

 remove a dominating tree of one species, because it threatens 

 to suppress a tree of another species, which must be preserved 

 for the sake of the mixture. To guard against an interruption 

 of the cover in such cases the dominated and even suppressed 

 trees must be more carefully husbanded than in pure woods, 

 until, with the advancing age of the wood, the mixture has 

 l)een secured. Frequent and light thinnings are in such 

 cases indicated. Their actual degree depends much on the 

 light requirements of the more valuable species in mixture. 

 The operation is facilitated if the several species are mixed by 

 groups instead of by alternating single trees. 



Where a valuable timber species is mixed with a less 

 valuable one, the former must be favoured from an early age, 

 so as to bring it to the highest possible development, if neces- 

 sary at the expense of the less valuable species. As long as 

 the valuable species is of quicker growth than the other, the 

 operation is comparatively simple ; but if it is of slower growth, 

 all individuals of the secondary species which threaten to over- 

 top it must be cut away, until the principal species is secure. 



5. Tliinniiig of Coppice Woods. 

 These thinnings are conducted according to the same 

 principles as in high forest, whenever the number of shoots 

 is so great that there is not enough growing space for all. 

 More especially in oak coppice the quality and quantity of 

 bark may be considerably influenced by leaving on each stool 

 only the two or three best shoots and removing the others. 

 Such thinnings are generally made in the second half of the 

 rotation. In coppice with standards, such thinnings are 

 frequently required to set free seedling plants growing 

 amongst the coppice. 



