110 AN AUSTRALIAN STUDY OF AMERICAN FORESTRY. 
Their fundamental purpose is to record timber sales and working plan 
data, and their development is correlated, therefore, with the collection by 
the Offices of Silviculture, Lands, Operations, and Grazing, of information 
with regard to stumpage (royalty) appraisals, forest types, age classes, site 
qualities, soil classification, forage types, fire protection, permanent improve- 
ments, silvicultural provisions, timber estimates, and any other purposes 
requisite for effective management. 
For the present the work is to be restricted to areas where operations 
are in progress or in prospect, or in which there is danger of exceeding the 
requirements of established plants, or the interests of local communities. 
A skeleton map of the area to be surveyed is prepared on a 20-chain 
scale, and on it is plotted all existing data. 
This map becomes the “camp map.” 
A preliminary field inspection is then carried out by the chief of party, 
accompanied generally by the forest supervisor and perhaps also by a member 
of the district office. 
It covers the following points :— 
(1.) The desirability and probability of an immediate sale. 
(2.) The specific problems on the forest. : 
(3.) The area which should be covered by reconnaissance. 
(4.) In detail, what data will be necessary, and exactly how they 
will be obtained. 
(5.) The plan of topographic control. 
(6.) The percentage (5 per cent. or 10 per cent.) which should be 
estimated. 
(7.) The size and organisation of the party. 
(8.) The necessary equipment, transportation facilities, trail con- 
struction required, possible camp sites, etc. 
(9.) A tentative division of the area into blocks and chances and, if 
possible, its relation to the forest as a whole. 
(10.) Deviations, if considered advisable, from the district instrue- 
tions. 
(Instructions for intensive reconnaissance, 1914.) 
As a result of this preliminary inspection, a complete plan of work is 
prepared in the form of a letter of instruction to the supervisor, and is 
submitted to the district forester for his approval and signature. 
United States of America Forest Service mapping combine the features 
of both cadastral and topographic surveying. 
There are three divisions of the work, viz., primary, secondary, and 
tertiary control. 
Primary control has as its object the orientation of the survey on the 
earth’s surface. 
It is seldom necessary in forest practice because of the foundational work 
of the geological and lands surveys. 
Secondary control consists of the horizontal and vertical extension from 
the primary control, of a framework of traverses upon which to hang the 
topographic details. 
