3i8 APPENDIX 



young growth is freed (set free) from oppression by removal of woK 

 trees. 



G., Freistellen. F., degager. 



Severance felling or cutting. The clearing of a narrow strip on the 

 border of a young stand to stimulate the root development and reten- 

 tion of branches of the bordering trees, producing a windfirm mantle, 

 and thus preparing them for subsequent exposure to wind when an 

 older stand on the windward side of the strip has to be removed before 

 the utilization of the younger stand. 



Thinning. A cutting made in immature stands after the saphng 

 stage for the purpose of increasing the rate of growth of those trees 

 which are left. 



G., Durchforstung. F., eclaircie. 



Degrees of thinning are indicated by tne following grades. They 

 may be gauged by volume and by number of trees removed. 



Grade A — light. A removal of dead and dying trees. 



Grade B — moderate. A removal, in addition, of all suppressed trees 

 and the poorest intermediate trees. 



Grade C — heavy. A removal, in addition, of the rest of the inter- 

 mediate class of trees. 



Grade D — very heavy. A removal, in addition, of many of the co- 

 dominant trees. 



German and Austrian experiment stations recognize four grades; 

 Gayer 1 recognizes three grades, as follows: 



Light (G., Schwach). Removal of dead and whoUy suppressed. 



Medium (G., Mittelstark). Removal of suppressed and the greater 

 portion of the dominated trees (intermediate class). 



Heavy {G., Stark). In addition, cutting operations in the co-domi- 

 nant class. 



Interlucation. A severe opening up of a stand. Sec fuller definition 

 under its letter. 



Selection thinning. A thinning in which always the stoutest trees 

 are removed, as in the selection method of regeneration (Borggreve). 

 Intermittent management. The management of a forest for a periodic 

 instead of annual yield. 

 G., Aussetzender Betrieb. 



1 Der Waldbau, Dr. Karl Gayer, Berlin, 1888. 



