18 Miscellaneous Circular b8, U. S. Dept. of Agriculture 



mining camps. Added to this is the damage caused by smelter 

 fumes. Old-time methods of smelting involved the use of wood and 

 charcoal, both of which admitted of cutting the forests absolutely 

 clean. The deadening of the forests through the use of fire so cheap- 

 ened the work of cutting that it was customary to keep the fires 

 burning two or three years ahead of cutting operations. 



Near Anaconda the timber on thousands and thousands of acres 

 has been entirely killed by smelter fumes. Practically all of this 

 timber that was suitable for use in the mines has been taken out, but 

 utilization is less complete than formerly, because there is no longer 

 need for charcoal. The continued presence of the fumes prevents 

 reproduction. These areas are therefore lost for timber growing. 



Fig. 11. 



-A mine tunnel on the Jefferson National Forest. A prospector may stake 

 a claim wherever he finds evidences of valuable minerals 



The elements in the smelter fumes that are destructive to trees con- 

 sist almost entirely of sulphur dioxide and trioxide gases, which are 

 produced in the smelting of sulphide copper ores. 



Through improved methods of smelting, the damage to the forests 

 is being somewhat reduced. This, with the prevention of fires 

 through national forest administration, is resulting in bringing some 

 of the land back to forest production. At the same time all clean 

 cutting has been stopped by the Forest Service. The creation of 

 national forests has therefore contributed greatly to the permanence 

 of the near-by timber supply for mining purposes, as well as to 

 stream-flow regulation by keeping a constant forest coyer on water- 

 sheds. 



