186 NATURAL REGENERATION 



thinner canopy is admissible on northern aspects than on 

 southern aspects, if other conditions are similar. 



There is a greater necessity for shelter on southern 

 aspects than on northern aspects, for there is a greater 

 liability to early spring and late autumn frosts ; and humus 

 will disappear more rapidly, and the soil will more quickly 

 get heated. But if there is a reasonable shelter wood, it 

 will of itself, directly, afford protection from frosts, and also 

 indirectly, by preserving humus, and thereby delaying the 

 date of active vegetation in the spring. 



When, however, an area is well seeded, there should be 

 no unnecessary delay in removing the mother trees, and the 

 sooner their shade can prudently be dispensed with, the 

 more moisture will the young crop obtain, in the shape of 

 rain and dew, and also from the soil. But if the removal of 

 the shelter trees were to cause the appearance of grass and 

 weeds, there would be less moisture available for the young 

 seedlings. 



However, when the young crop is once well established, 

 and thick on the ground, it will of itself prevent much of the 

 evil effect that would otherwise result to the soil on account 

 of the removal of the mother trees. 



Natural regeneration sometimes fails owing to a rank 

 growth of grass, which is either due to bad management, or 

 to a seed year having been insufficient, or the quality of the 

 seed being bad, or to some unavoidable circumstance. In 

 such cases, artificial aid in the shape of soil preparation, and 

 usually of planting seedlings, should be given. 



It is not easy to get an even natural regeneration over 

 any large area. It will usually be necessary to complete the 

 process by artificial means. 



Usually a wood is regenerated for one species only, but a 

 mixture can be produced by introducing artificially other 

 species, when the mother trees (or most of them) have been 

 cleared. 



For instance, on an area naturally regenerated for Beech, 

 quick-growing trees, such as Larch, Ash, Poplars, may be 

 planted singly, or in groups or patches, but slow-growing 



