FOREST UTILIZATION 25 



timber bars, which are held in place by stone 

 cribs. 



These booms are stretched diagonally across the 

 river. The logs or wood are merely diverted 

 by the boom and forced into an artificial side 

 canal ending in a reservoir near the mill or 

 depot. 



A gridiron or sieve, filtering the river at a water- 

 fall and retaining the wood on the gridiron, has 

 been used in the Tyrol by the Bavarian Govern- 

 ment for many decades. 



(b) The American boom consists of two sections, an 

 upper shear boom spanning diagonally across 

 the stream and a lower storage boom stretch- 

 ing for miles along the river bank, where the 

 water is quiet and ' the current slow. Both 

 booms are floating booms consisting of one or 

 two strings of prime logs, the logs joined by 

 anchor chain. The booms are kept in place 

 either by wire cables ^-inch to an inch in 

 diameter or by stone filled cribs. It is ad- 

 visable to have the storage boom consist of 

 independent sections so that the breakage of 

 the boom empties one section only. 

 Frequently several mill concerns form Boom com- 

 panies. 

 The logs are lifted out of the booms by "jack 



works" or "log hoists." 



VII. Driving and splashing must be considered a backwoods 

 method, applicable to very cheap stumpage. It is not 

 practiced on the Pacific coast, where we have very cheap 

 stumpage, owing to the size of the logs and poor water 

 facilities. Where there are plenty of natural lakes, in a 

 coniferous country as in the Adirondacks, Michigan 

 and Minnesota, the method continues to be practiced. 

 Splashing is the more advisable: 



(a) The smaller the specific gravity of timber. 



(b) The shorter the logs. 



(c) The lower the stumpage price. 



(d) The more reliable the rainy season and the gauge 



of the river. 



(e) The better the natural conditions are at the dam 



sites, in creek bed and at boom site. 



(f) The poorer the natural conditions are for railroad 



building and wagon road building. 



(g) The less land owned by other parties is traversed 



by splashed logs. 



