THE FOREST ATLAS. 73 



The atlas sheets show the alienation of lands within 

 National Forests, but it must be understood that data 

 of this kind can not be accepted as final authority, but 

 may be regarded as presumptive evidence. It has re- 

 quired three years to collect the alienation data for the 

 National Forests, and since their status changes from 

 day to day, while the compilation and publication of 

 atlas sheets requires several months, it is evident that a 

 folio can not be issued to forest officers which will be 

 up to date in this respect. It is only by keeping new 

 data posted on the sheets that the office record can be 

 kept up to date. 



Maps are never perfect, nor do they approach perfec- 

 tion unless repeatedly altered and corrected in accord- 

 ance with dicoveries or changed conditions. Although 

 the Forest Atlas sheets are compiled in every case 

 from the best data available, they are often far below 

 the standard which should obtain in forest maps. 

 It will not be regarded as a reflection upon the compiler 

 of a sheet if a large number of corrections are found 

 necessary, and field officers should never hesitate, for 

 this reason, about sending in data. 



The coloring tints which are used in the classification 

 scheme may be prepared as follows from standard inks 

 that will be furnished by the property clerk at Ogden, 

 upon requisition : 



Forest Atlas Color prescriptions, 

 Timberland: 



Less than 2,000 board feet per acre Parts. 



Green ink 2 



Yellow ink 1 



Water 3 



