APPENDIX 321 



G., normal. F., normal. 



Normal age classes. The presence of a complete series of age classes 

 corresponding to the rotation (see Age class). 



Normal age class distribution. Such distribution of age classes as 

 will permit annual or periodic fellings to be made without damage to 

 adjoining stands. 



Syn. : normal age class arrangement. 



Normal increment. The best average increment attainable by given 

 species on given sites, as represented in normal yield tables. 



Normal forest. A standard with which to compare an actual forest 

 to bring out its deficiencies for sustained yield management ; the con- 

 ception of an ideally regulated or organized forest; a forest with 

 normal increment, normal age classes in size and distribution, and 

 normal stock. 



Normal growing stock or Normal stock. The amount of material 

 represented by the stands in a normal forest ; practically, the contents 

 of the normal age classes as represented in normal yield tables. 



Normal yield table. An accepted standard yield table with which 

 to compare actual yields. The statements of a normal yield table are 

 derived as an average from the best producing fully stocked areas for 

 given species and sites. If a normal forest were not merely an idea, 

 but actually attainable, the normal yield table would represent its pro- 

 ductivity and stock. 



Normal stand. A stand fully stocked and in proper growing 

 conditions, conforming to the yield table and having normal incre- 

 ment. 



Normal form factor. See Form factor. 



Nurse tree. A tree which protects or fosters the growth of another in 

 youth. 



G., Schutzholz. F., essence d'abri. 

 Nursery. See Forest tree nursery. 

 Old growth. See Virgin forest. 

 Open, a. See Crown density. 

 Oppressed. See Crown class. 

 Organization. See Forest organization. 

 Over-cut. The cutting of a quantity of timber in excess of the annual 



growth of the forest or of the annual felling budget. 

 Overmature forest. Forest on which, as the result of age, growth has 



