NATURAL REGENERATION. 139 



considered a most important cultural measure. At the 

 same time it is expensive, and should be executed 

 only when necessary. 



ii. STRENGTHENING THE SHELTER TREES. 



After the ground has actually become stocked with 

 seedlings, only a certain number of the trees forming 

 the original wood will remain on the ground to afford 

 shelter to the young crop a^id the soil. If all the rest 

 of the wood were removed at one cutting, so that the 

 above-mentioned shelter trees were suddenly brought 

 from a crowded into a comparatively open position, they 

 would probably be thrown by the first gale. To avoid 

 this they must only gradually be placed in a more 

 open position, so as to obtain a firmer hold of the 

 ground. This is done by the preparatory cuttings. 



The trees which are to form the ultimate shelter-wood 

 must be selected from the beginning ; they should 

 be trees with neither exceptionally broad nor narrow 

 crowns, but healthy trees with medium crowns. These 

 must gradually be led over from a crowded to a more 

 open state. It follows that, from this point of view, the 

 preparatory cuttings are of more importance in the case 

 of shallow- rooted species and very dense woods than 

 under opposite conditions. 



iii. STIMULATING THE PRODUCTION OF SEED. 



In some cases placing the trees in a more open 

 position has a beneficial effect upon the production of 

 seed, but this cannot always be relied on, as frequently 

 such a measure is followed by increased production of 

 wood instead of seed. 



