4. 



GIRDLING, FRILL. A single line of axe cuts overlapping downward 

 and leaving a frill into which toxic materials may be 

 poured. (SAF) 



GROWING STOCK. The sum, by number or volume, of all the trees 

 growing in the forest or a specified part of it. (BCFT) 



HERBICIDE. A phytotoxic chemical used for killing or inhibiting 

 the growth of plants. (SAF) 



HUMUS The well decomposed organic matter of the soil which may 

 form a separate layer or be intimately mixed with the 

 mineral particles. (BCFT) (See Duff and Litter.) 



IMPROVEMENT TREATMENT. This is a special form of thinning which 

 applies particularly to stands that have been mismanaged 

 or not previously managed and which may be accomplished 

 by cutting, girdling, or chemical methods.* 



INCREMENT. The increase in diameter, basal area, height, volume, 

 quality or value of individual trees or crops during a 

 given period. (BCFT) 



LIBERATION. An operation to free a young stand, not past the sap- 

 ling stage, from the competition of older overtopping 

 individuals. Release may be accomplished by cutting, 

 girdling, or chemical methods. (SAF modified) (See Appendix.) 



LITTER. The uppermost layer of organic debris on a forest floor, 

 freshly fallen or only slightly decomposed, and consist- 

 ing chiefly of leaves but also including bark fragments, 

 twigs, etc. (BCFT) 



LOAM. A soil composed of sand, silt, and clay in such propor- 

 tions that the properties of the soil are not dominated 

 by any one of them. Loam is characterized by a friable 

 structure. (BCFT) 



MANAGEMENT PERIOD. The period for which detailed prescriptions 

 are laid down in the management plan.* 



MANAGEMENT PLAN. The means by which forest policy, aims, and 



objectives are translated into a continuity of specific 

 treatments for a particular forest area.* 



MANAGEMENT SYSTEM. A set of procedures co-ordinated for the attain- 

 ment of the management objectives.* 



MANAGEMENT UNIT. A forest area under one ownership or assigned 

 rights to the timber thereon, organized for efficient 

 administration and control and operated according to one 

 management plan.* 



MERCHANTABLE TIMBER. Those portions of a tree or crop which can 

 be marketed under given eccnor.-' <* ~o"ditions. (BCFT) 



