CHAPTER XVII. 



WOEDS AND PHRASES, 



Absolute Forest Land. Land fit only for forest growth. 



Accident Yield. Trees which are cut on account of ac- 

 cident, as, for example, damage by wind, snow, insects 

 or fire. 



Accretion. Increase in diameter or height; distinguished 

 from increment, increase in volume. 



Accretion Borer. An instrument for determining the 

 growth in diameter of standing trees. It consists of a 

 hollow auger, which when bored into a tree, extracts 

 a section showing the annual rings. 



Accretion Thinning. A thinning made specifically to in- 

 crease the rate of growth in diameter of the trees 

 which are left standing. See thinning. 



Actual Merchantable Length. See used length. 



Actual Merchantable Volume. See used volume. 



Advance Growth. Young trees which have sprung up 

 in accidental openings in the forest, or under the 

 forest cover before reproduction cuttings are begun. 

 See volunteer growth. 



After Growth. Young trees which have sprung up as 

 the result of reproduction cuttings. 



Age Class. All trees in a stand whose ages are within 

 a given limit. 



Alder Grab. The stem of an alder, or other small tree, 

 which is bent over and plugged into a hole bored In 

 a boom stick, or secured in some other way, to hold 

 a boom of logs inshore. 



Alligator. 1. A boat used in handling floating logs. 

 It can be moved overland from one body of water to 

 another by its own power, usually applied through 

 drum and cable. 2. A device, often made from the 

 fork of a tree, on which the front end of a log is 

 placed to facilitate skidding on swampy ground. 



Anchor Line. A line attached to a small buoy and to 

 one fluke of an anchor used in towing a raft of logs. 

 It is employed to free the anchor when fast to rocks 

 or snags. 



Annual Ring. The layer of wood produced by the di- 

 ameter growth of a tree in one year, as seen on a 

 cross section. See false ring. 



Apron. 1. A platform projecting down stream from 

 the sluiceway of a dam to launch well into the stream 



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