SILVICULTURE. 



175 



windward side. This "strip method," just as any 

 method which relies upon the seed furnished by a 

 neighboring growth, is more successful with those 

 kinds which have light-winged seeds, easily carried 

 by the winds over the area to be seeded, and which 

 do not require any protection in their infantile 

 stage. It is a method which, on account of the 

 greater concentration in harvest, is probably advis- 

 able in many cases in the United States. 



For heavy-seeded kinds like oaks, beech, hick- 

 ories, and other nut trees, the more complicated 

 method of " regeneration under shelter wood or 

 nurse trees" becomes necessary ; this consists in a 

 series of severe preparatory thinnings of the old 

 crop which is to be reproduced, beginning a year or 

 more before the time when a full seed crop is to be 

 expected, seed years recurring more or less period- 

 ically. These preparatory thinnings are made for 

 the purpose of exposing the soil to atmospheric 

 influences, which hasten the decomposition of the 

 litter, thereby securing a serviceable seed bed. 

 Enough trees of the kind to be reproduced are 

 left on the ground to secure full seeding and 

 shelter and protection of the young crop. When 

 the latter has come up, the nurse trees are gradually 

 removed to give the young seedlings the required 

 light. The whole operation, until the last nurse 

 trees are removed and the young crop is established, 

 may take from three to ten and more years, accord- 

 ing to kinds, soil conditions, climate, and success 



