AMEEICAX SYLVICULTURE 



type is bastardized with the cleared group type or with the shelter- 

 wood group tj'pe, 



IIL The type as a means of regeneration, in its purity, is possi- 

 ble only where 



a. The compartments contain a mixture of all age classes, 

 with the hypermature classes not too badly prevailing; 



b. The species to be regenerated is an intense shade-bearer; 



c. The soil is strong enough to allow light-demanding seedlings 

 a chance at surviving a long period of partial suppression. 



IV. The species removed — presumably the most valuable species 

 — has its prospects of propagating reduced, struggling against com- 

 peting species, the nvmiber of its seed trees being relatively 

 decreased. 



V. Small chance for reinforcing. 



VI. Impossibility of protection against fires under headway. 



Paragraph XLVII. Types in which lumbering 

 coincides with N. S. R. 



In these types of natural seed regeneration — so-called shelter- 

 wood types — lumbering and reseeding go hand in hand, both pro- 

 gressing seriatim, slowly, cautiously. In the pure types, no tree is 

 removed, unless the removal has a distinct bearing — or is expected 

 to have it — on the production of a progeny or on its further develop- 

 ment. Seedlings less than hve years old usually stand within a 

 few yards of their mothers. This distance is gradually increased — 

 in the course of up to fifty years — until the youngsters do not 

 require any more, or rather despise, the benefit of the parents' 

 presence. 



Lumbering operations are carried on — in one and the same 

 limited lot — during a number of years. 



Where the mother trees are very rapidly removed, after re- 

 seeding, from the proximity of the youngsters, the shelterwood 

 types approach the types of cleared compartments, cleared 

 strips, etc. 



Where the mother trees are very slowly removed, after reseed- 

 ing, from the proximity of the youngster, the shelterwood types 

 approach, or bastardize with, the advance growth types. 



A. The chances for success depend on: 



I. Sylvicultural talents of the forester in charge and of his 

 staff, also on the size of the ranges. 

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