260 COLLECTION OF STATISTICS. 



done by professional surveyors ; the following remarks refer 

 only to those points in which the forester must participate. 



Before the survey is commenced, various preliminary 

 matters must be attended to, such as : 



(1) Regulation 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, pas- 

 tures, 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 con- 



sisting of different species, or -different ages, or 

 different quality classes. The latter is only neces- 

 sary in very valuable forests. 



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

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

 accurate 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 staff. 

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

 partments, 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 



