NATIONAL FOREST RESOURCES 183 



timber the maximum stump height is ordinarily 

 fixed at 18 inches, and merchantable timber must be 

 used to a specified diameter in the tops, which is ad- 

 justed for each species in accordance with local 

 manufacturing and market conditions. The officer 

 in charge of the sale is authorized to vary the stump 

 height and top diameter in individual cases when 

 those specified in the contract are not practicable. 

 The tops must be trimmed up and, as a rule, brush 

 must be piled and burned, or burned without piling 

 under the direction of Forest officers. Merchant- 

 able timber which is not cut and removed and 

 unmarked trees which are cut must be paid for at 

 double the specified stumpage rates. This extra 

 charge serves as a penalty. 



All camps^, buildings, railroads, and other im- 

 provements necessary in logging and manufactur- 

 ing the timber may be constructed upon National 

 Forest land without charge. Railroads which open 

 up inaccessible regions may be required to be made 

 common carriers or to transport logs and lumber 

 for other purchasers or for the Government at 

 reasonable rates. 



Since fire protection is one of the most important 

 duties of the Forest Service, provision is made in 



