174 THE USE BOOK. 



Under this head will come also the cost of turn-outs, retaining 

 walls, side ditches, and all other items pertaining to the roadbed. 



Cost per mile for culverts and other small waterways. 

 With the necessary size noted it is an easy matter to estimate 

 the cost of each culvert and bridge. 



Cost of powder, tools, and other supplies. 



TRAILS. 



There is urgent need of more and better trails on 

 most of the National Forests. They are of capital im- 

 portance, because they are not only the best insurance 

 against fire, but one of Ihe chief means by which the 

 Forests can be seen and used. 



A general system or scheme of trails for the whole Forest 

 should first be carefully thought out and decided upon, and 

 those of the greatest immediate importance for protection and 

 patrol should be built first. Trails urgently needed may be 

 made good enough for ordinary saddle-horse or pack-train travel 

 at once, with a view to improvement and permanence later on. 



The most important part of trail work, and that for which 

 the supervisor will be held directly responsible, is the pre- 

 Jiminary location .of the line. and grade. The location of a traTl 

 should always begin From the^ summit which is to be reached or 

 crossed by it, and the lineshould be located toward the foot of 

 the grade. Location from the bottom toward the top should 

 never be attempted. Construction work should not begin until 

 satisfied that the best route has been selected. 



The maximum grade of all Forest trails should be 20 per 

 cent^ unless the^ expense of keeping within this limit is^ab- 

 sohiteJjIIprohjbiJLiie. When it is found necessary to build 

 switch backs, the turns should be level and wide enough to give 

 plenty of room for a loaded pack^mimal. 



"Logs7 snags, brush, or limbs that require turn-outs on a trav- 

 eled trail will be considered as marks of inefficiency on the part 

 of the ranger in whose district they are found, 



