WORDS AND PHRASES 471 



Crib. Specifically, a raft of logs; loosely applied to a 

 boom of logs. 



Crib Logs. To surround floating logs with a boom and 

 draw them by a windlass on a raft, or to tow them 

 with a steamboat. 



Cross Chains. Chains connecting the front and rear 

 sleds of a logging sled. 



Cross Cutter. See bucker. 



Cross Haul. 1. The cleared space in which a team 

 moves when cross hauling. 2. To load cars or sleds 

 with logs by horse power and crotch or loading chain. 



Crotch. To cut notches on opposite sides of a log near 

 the end, into which dogs are fastened. 



Crotch Chain. A tackle for loading logs on sleds, cars, 

 or skidways by cross hauling. 



Crotch Tongue. Two pieces of wood, in the form of a 

 V, joining the front and rear sleds of a logging sled. 



CrowTi. In silvics, the upper part of a tree, including 

 the living branches with their foliage. In forest 

 measurements the use of the term varies with the kind 

 of tree and the purpose of the measurements. For 

 example, crown may be used to designate the whole 

 leaf and branch system or that portion of it above a 

 dead or a growing branch of a given size. In tree 

 description the crown is described as long or short, 

 broad or narrow, compact or ragged, conical or flat. 



CroAvn Class. All trees in a stand occupying a similar 

 position in the crown cover. Dominant, intermediate, 

 overtopped, and suppressed trees each constitute a 

 crown class. 



Crown Cover. The canopy formed by the crowns of all 

 the trees in a forest, or, in an irregular forest, by the 

 crowns of all trees in a special crown class. 



Crown Density. The density of the crowns of the trees 

 in a forest; it is usually measured by the extent to 

 which the ground is shaded. The degrees of crown 

 density in a forest are expressed in the following 

 terms: Closed. "When the crowns form an uninter- 

 rupted cover and permit little or no sunlight to reach 

 the ground. Dense. When three-fourths or more of 

 the ground is shaded. Thin. When three-fourths to one- 

 half of the ground is shaded by the crowns. Open. 

 When less than one-half the ground is shaded by the 

 crowns. Park forest is a forest in which shade occurs 

 only in isolated patches, under single trees or small 

 groups. 



CrowTJ Fire. See forest fire. 



