194 ELEMENTS OF SYLVICULTURE. 



It is chiefly in mountainous regions, on the sea 

 coast, or on the edges of unsheltered plateaux, that 

 this rule must be rigidly followed. In the majority 

 of cases it loses its importance in the plains in those 

 forests where the oak is the dominant species. 

 Nevertheless it is always prudent to conform to it, 

 whenever the ages of the different crops are suffi- 

 ciently well graduated not to entail any serious 

 sacrifices. 



Besides the reserves, the underwood also must be 

 taken into account. Though it has nothing to suffer 

 from the violence of the wind, still it has much to 

 fear from the cold dry winds which blow from the 

 north and east. This danger is most marked in the 

 north-east of France, especially on the unsheltered 

 plateau of the Ardennes. This is not, however, a 

 sufficient reason for changing the general direction 

 in which the cuttings ought to succeed each other, 

 It is quite enough to leave a belt on the north-east, 

 which should be worked by selection. Not being 

 exposed to violent wind, this belt may be narrower 

 than in the preceding case, thirty or forty yards for 

 instance. 



KULE IV. In a mountainous country it is the 

 higher parts which are exposed to the wind. The 

 trees there are generally shorter-boled, but more 

 spreading, more firmly rooted, and growing wider 

 apart than in the less elevated situations. Their 

 stability is therefore greater, and their presence is 

 a protection to the trees lower down, which, being 

 taller and less firmly rooted, could not stand without 

 some shelter. This consideration indicates sufficiently 



