CONSERVATIVE LUMBERING. 47 



of tops which can not be used should ordinarily be cut 

 away enough to let the tops sink close to the ground, 

 where they will rot as speedily as possible. Dry 

 crowns propped clear of the ground by their branches 

 rot slowly, burn fiercely, and are very dangerous in 

 case of fire. (See PL I.) 



FIG. 30. Skidding with oxen. Washington. 

 SKIDDING. 



When the trunks have been sawed into logs, the lat- 

 ter are dragged away by horses, mules, or oxen, or in 

 some cases by a long wire rope which is wound on 

 the drum of a donkey engine. This is called "skid- 

 ding the logs." In this wa} r they are collected in piles 

 called "roll ways," or assembled in "yards," or other- 

 wise made ready for the next step in their progress to 

 the mill. 



