42 FOREST EESKKVE MANUAL. 



* 



only does ability to refer accurately to the location, charac- 

 ter, and amount of any timber applied for save much time in the 

 handling of the application by those in the field, but it is of 

 the utmost importance in order that the central office may be 

 prompt in final action upon the proposed sale. 



For this reason all land within the reserves which bears 

 commercial timber applied for, is to be surveyed into ' ' blocks " 

 and "districts" and mapped, estimated, and described in a 

 systematic manner. This work is to be done by the super- 

 visors or head rangers, with such assistance from the ranger 

 force as is necessary. 



Compasses, chains, blanks, and other necessary equipment 

 will be supplied the supervisors or head rangers, who will be 

 held responsible for them in case of loss, but not for unavoid- 

 able wear or breakage. In case the supervisor is not able to 

 do the required surveying and mapping, or has no rangers 

 who can do it, he should promptly inform the central office 

 and request the provision of a competent assistant. 



DISTKICTS AND DIVISIONS. 



The chief object in the creation of districts, is to simplify 

 specifications relative to the location of the blocks, each to 

 contain approximately 160 acres, the reference to which, with- 

 out classification into larger divisions, would entail unneces- 

 sary numbering and confusion. The district should seldom 

 contain more than 100 blocks, except when the region has 

 been legally subdivided into townships and sections, in which 

 case the district will consist of one township, 6 miles square, 

 containing 144 blocks of a quarter section each. 



In the case of unsurveyed land the form of the block should 

 be determined by the topography of the region. Valleys or 

 drainage basins usually form the best limits, not only because 

 they are easily mapped and referred to, but because all 

 blocks thus included are apt to be reached by the same road 

 or driving stream. For instance, one of the simplest and 

 most desirable forms is that of a district 2 or 3 miles wide 

 from rim rock to rim rock, and about 10 miles long, the stream 

 running longitudinally through the center. Should the valley 

 be much wider than this, it is better to make a long district 

 on either side the stream, each comprising one slope from 

 stream to top of ridge, than to attempt to make the districts 



