212 THE I'RIKCIPI.F.S f)F HANDLING WOODLANDS 



Other hand, the presence of :i great number of small trees 

 increases the difficiiltx- of fellinp; the trees and makinir up 

 the wood, and oflers a distinct hindrance to removintj; 

 the logs and wood. 



Practical Application of Thinnings in this Country. 

 — The principles outlined in the preceding pages serve 

 as a guide for practise. In actual application they are 

 necessarih' subject to considerable variation. The exact 

 measures to be used and the details of selecting the trees 

 must in every case depend on the requirements of the 

 given stand. The forester must diagnose the stand and 

 make the cuttings according to its peCLilinr needs. 

 Knowing the specific life characteristics and requirements 

 of the species and their capabilities under the gix'en site 

 conditions, he makes his thinning so as to accomplish m 

 the highest measure the objects of management. 



As regards the time at which to begin the real thin- 

 nings Dr. Mayr specifies from the .Ulth to the 40th 

 )ears in the life of the stand. The statement means, 

 however, that this is an average for a stand well estab- 

 lished, in which the necessary work of cleaning in earl\' 

 youth has already been made. It means also that this is 

 the period when thinnings ought ordinariK- to begin, it 

 often happens even in Kurope that it will not pav to make 

 thinnings even at 30 or 40 vears of age, on account of 

 poor market and logging conditions. 



There are man\- instances of \oung mixed stands 

 in which valuable species are being badiv crowded and 

 injured b\- those less x'ahiable, and in the long riin the 



