SURVEY AND DETERMINATION OF AREAS. 219 



Before the survey is commenced, various preliminary matters 

 must be attended to, such as : — 



(1.) Eegulation and demarcation of the boundaries of .the 

 forest, and of those parts, which are subject to 

 servitudes. 

 (2.) Demarcation of all areas, which are not destined for the 

 production of wood, such as fields, meadows, pastures, 

 swamps, rocky parts and other areas unfit for growing 

 woods. 

 (3.) The laying out of a suitable system of roads and rides, 

 in so far as it can be done without a map, or with the 

 help of a sketch map. What cannot be done in this 

 respect before the commencement of the survey, should, 

 if possible, be done during its progress, that is to say, 

 as soon as the necessary data become available. If 

 any part cannot be done until a map becomes available, 

 an additional survey will be necessary. 

 (4.) Demarcation of the boundaries between woods of 

 difierent species, ages, or qualities. The latter is 

 necessary only in valuable forests. 

 The method of survey depends on the value of the forest, as 

 represented by its returns ; the higher the latter, the more 

 minute should be the survey. Generally speaking, all main 

 lines, such as the boundaries of the property and of the areas 

 subject to servitudes, the roads and principal rides, should be 

 surveyed with the theodolite and chain or measuring staft'. 

 The details, such as the limits of woods and of sub-compart- 

 ments, may be done with the plane table or prismatic compass. 

 The area of the whole forest and its main parts should be 

 ascertained by the method of co-ordinates ; the area of the 

 compartments or woods may be ascertained with the plani- 

 meter, or a network of squares, each of which represents 

 a fixed area. 



Whenever practical, the survey should be based upon a 

 previous triangulation. 



The preparation of the maps will be dealt with in the last 



