FOREST BESEKVE MANUAL. 43 



reach eiitirel}'' across the valley by shortening their length. 

 In much-broken country, however, where small ravines are 

 numerous, several may be included in one district. In such 

 cases the natural outlet of the timber must be considered, and 

 canyons leading away from each other should not go into the 

 same distrct. 



As a rule, districts should not be less than 2 miles wide or 

 more than 10 miles long, and, except in the case of surveyed 

 land, when townships are considered districts, should not con- 

 tain more than 25 or 30 square miles. 



In order to insure permanence and ease in finding them, as 

 well as to save work in blazing, wherever possible, streams 

 roads, bare ridges, cliffs, or burns should form the boundaries 

 of both blocks and districts. Where, however, the uniformity 

 of the region makes artificial lines necessary, they should be 

 plainly blazed and all blazes stamped with the United States 

 marking hammer, to identify them as the work of forest officers. 



In all cases corners must be marked by posts or monuments 

 and witness trees. The side of the post toward each district 

 should be faced and marked with the initial and number of 

 the district, viz, "D-2,0." The witness tree bears the same 

 mark. 



The areas of the districts need not be computed, nor the 

 boundaries actually measured, although for the purpose of 

 mapping it may often be necessary to record the compass 

 direction of the latter. When a fairly accurate map of the 

 reserve already exists it will be sufficient to outline the dis- 

 tricts upon it, accepting the correctness of the streams and 

 ridges forming the natural boundaries. The surveyed and 

 blazed boundaries may be drawn from their recorded distance 

 and compass direction from some known point on the map. 

 If, for instance, a district is bounded on the east by a stream 

 and on the west by the summit of a parallel ridge, both of 

 which features are shown upon the map, the north and south 

 boundaries should be run by compass and located by measure- 

 ment to some object, such as a fork or bend of the stream, or 

 a road or building, also shown on the map. If no good map 

 of the region exists, a map must be made for each district. 

 Measurement of distances will not be required, but approxi- 

 mations should be made with great care, and triangulation 

 should be done wherever possible. 



