AN AUSTRALIAN STUDY OF AMERICAN FORESTRY. 113 
“The unit of estimation is the 40-acre block. Tallies are kept separate 
by types and logging areas, and in even-aged stands by age classes.” In 
uneven-aged stands estimates include (a) all merchantable timber; (6) where 
needed for regulation a division of the stand into age classes based on dia- 
meters ; (c) data on age classes below merchantable size for determination of 
increment and purposes of management. 
The officer in charge deals with the more difficult questions such as 
logging costs, silvicultural systems, cutting policies, etc. 
All the topographic detail collected is fitted into the camp map and 
inked in by the topographer before the party leaves the field, so that the final 
maps can be prepared forthwith by the district office drafting staff. 
Timber types and other special data for the project are not shown on the 
camp map, which is regarded purely as a topographical base map. 
The final maps are prepared from the camp maps, either in the form of 
tracings from which white prints are made, or as photolithos by photo reduc- 
tion. It is these white prints which are used to record timber cover, soil, and 
grazing data. 
The final result is four maps. showing respectively— 
(1.) Topography and culture; 
(2.) Types and age classes ; 
(3.) Timber estimates by 40-acre “sections”; and 
(4.) Improvements planned. 
The estimates are computed and checked in the field or as soon after as 
possible. For convenience in stumpage appraisals they are summarised by 
blocks and logging areas and where deemed advisable by age classes for each 
type, giving in all cases the amounts to be cut and to be reserved. 
In map-making, a standard scheme of colours, signs, and symbols has 
been designed and adopted. 
Drainage is shown in blue, contours in brown, and “ culture” in black. 
Lo) 3 3 
There are separate type “legends” for land classification; logging; 
planting; fire; and grazing. 
The basis of the land classification legend is not the forest type, but the 
density of stocking. 
There are five density types, shown in five shades of green, and varying 
from 2,000 to 50.000 feet (sawn output) per acre. Woodland, scrub, waste, 
burns, etc. are shown in other colours. The progress of exploitation is shown 
by hatchings, and the status of land by initial letter symbols. 
Forest types are indicated by a very clever scheme of alpha-numeric 
symbols. which show the composition, character, and stand of any forest, and 
which is so much simpler and more effective than the symbolisation table I 
designed for assessment work in the north-west of New South Wales in 1912 
that I have no hesitation in recommending its adoption in lieu thereof. 
The svmbolisation is by letters and numbers instead of by hieroglyphs, 
and follows a carefully devised plan for assisting the memory. 
