56 ELEMENTS OF SYLVICULTURE. 



quently found in mountainous country, where it has 

 to bear the weight of superincumbent snow and hoar 

 frost, compels us to postpone the moment for 

 thinning out the stock. The first periodical thinning 

 then is not to be made until the crop has distinctly 

 attained the size of low poles. At this stage the well 

 marked difference in size of the suppressed trees will 

 point them out as having to fall, and there will not 

 be much risk of making any gross mistake. Until 

 the trees have attained their full height, the thinnings 

 should remain moderate. From this time forwards 

 it will prove expedient to open out the stock rather 

 more without ever going so far as to thin severely. 



III. TEEATMENT OF HIGH FOEEST OF OAK AND 

 BEECH MIXED. 



ADVANTAGES OF THE MIXTUEE. From the nature 

 of the soil suitable to the beech, it is chiefly with 

 the sessile-flowered oak that we find it naturally as- 

 sociated. Many are the advantages of this mixture. 



(i.) The two trees require the same climatic 

 conditions, and though the beech is not so long lived 

 as the oak, it suffers no harm from having to wait 

 until the latter is old enough to be exploitable. 



(ii.) Their roots penetrate the soil in different direc- 

 tions, and this allows a greater number of trees tc 

 flourish on a given area without injury to each 

 other. 



(iii.) The cover of the beech is dense, and comes in 

 as a corrective to the baneful influence exercised on 

 the soil by the light cover of pure oak. 



