REGENERATION FROM ADJOINING WOODS. 249 



c. SecurHij (ujainst crfernal Ddnijcis. 

 These are chieflj^ frost, drought, and a growth of weeds. 

 Some protection will be given by the adjoining wood, but the 

 amount depends on the breadth of the area under regeneration 

 at one time, and the relative position of the mother trees. 



(1. Extent of the (J tear inn . 



The smaller the regeneration area is, the more satisfactory 

 will be the results. On large areas a period of 10. 20, or more 

 years may be required to complete the new crop, which will 

 be very uneven, and in the majority of cases artificial sowing 

 and planting has to step in. 



The chances of success are much greater if the regeneration 

 area has the shape of a narrow strip running along the edge 

 of the mother trees. The breadth of such strips should not 

 exceed the height of the mother trees, so that the area may 

 l^e quickly and fully stocked, and better protection provided 

 for the young crop against climatic dangers ; the soil keeps 

 also fresher. 



Such protection is further increased if successive clearings 

 do not adjoin each other, but are separated by older woods. 

 Sometimes the clearings represent patches situated in the 

 middle of old woods. Arrangements of this kind lead, how- 

 ever, to a verj' complicated system of management ; lienee 

 they occur only where groups of trees have been thrown by 

 wind or snow, or killed by insects. If patches are cut 

 purposely, they often lead to the group system described 

 above. 



2. Merits of the System. 



Owing to the uncertainty of the seeding and the injuries to 

 which young tender plants are exposed, the system can be 

 recommended only under favourable conditions of the locality 

 and in case of hardy, quick growing species. Damage by 

 insects, especially the cockchafer, Hylesinus, and Hyhirgus, 

 further narrows the limits of applicability. 



