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ANNEXURE M 
THE APPLICATION OF AIR PHOTOGRAPHS TO FORESTRY IN AUSTRALIA 
Introduction 
The use of air photographs is now an integral and important part of forestry 
practice in Australia, The economie situation created by the demands of a growing popu- 
lation for inereased timber supplies has provided the stimulus for the development of more 
efficient methods of forest management, Perhaps the most important of these is the prae- 
tical application of aerial photography. 
Foresters have to deal with a biological population whose extensive geographic 
dimensions have, over the years, posed many difficulties, 
The total forest resources of Australia have never been assessed on a nation- 
wide basis, although this has been recommended at a number of international and interstate 
forestry conferences over the last 20 years. Following overseas experience, aerial 
photos have been adopted for use in the national forest inventory, and have formed the 
very basis for all the work so far completed in this field, 
In the past, vast tracts of land have been considered inaccessible, If the 
increasing demand for timber is to be met, some of these inaccessible areas have to be 
brought into production. How is it possible to decide whether or not an “inaccessible 
area" will be economically productive if expensive access roads are provided? The air 
photo provides a reasonable solution to this problem, and is employed to a very great 
extent in preliminary reconnaissance work, 
Many of the other tasks facing the field officer can be time-consuming and hence 
costly if field work is the normal method by which the necessary information is obtained, 
If the air photo is incorporated into the work where practicable, tremendous savings of 
time and money can be made, and in some cases the precision of a job can be increased, 
Since most forest services are required to adhere to very strict budgets, sav- 
ings of this nature are becoming more necessary if the quantity of wark produced is to 
increase, 
Aerial photos have been used by foresters for over 20 years, but it is only in 
recent years that they have come to appreciate the tremendous assistance to be gained by 
their use, and to change their methods to suit this aid, In fact, in Australia, the 
training of professional foresters has included an introduction to the use of air photos 
in forestry only in the last few years, 
Before considering just how air photos are used by the forester, one most impor- 
tant point should be stressed, Fieldwork cannot be wholly replaced by using photos, but 
a well-balanced integrated programme of field and photo work is essential. 
Forestry's uses of air photos are best considered as falling into the two 
following categories - 
1. Mapping. 
2, Interpretation. 
Mapping 
The techniques of mapping from aerial photographs are well established and will 
not be considered in this report, It is important to mention here that in general it is 
not a function of the forest service to produce base maps, Cadastral, military, plani- 
metric and topographic maps are the responsibility of civil and defence mapping author i- 
ties, and are usually available to forestry. Sometimes however, the absence or unsuita- 
bility of these maps force forestry to produce its own base maps. Under these circumstances, 
recourse is usually made to a combination of a slotted template assenbly and transference 
of detail by relatively simple low order accuracy equipment such as a Sketchmaster or 
Multiscope, or by radial line technique, 
The maps thus produced are not highly accurate, but are quite satisfactory for 
forestry urposes, The forester does not require the same accuracy as the engineer does. 
As Spurr (Aerial Photographs in Forestry - 1948) says, it is pointless to insist on map- 
ping techniques capable of plotting to within 10 feet, if for example, the features to be 
plotted cannot be located any closer than 30 feet on the ground, An example is forest 
type boundaries which are generally rather indefinite, especially in the native Australian 
forest, and difficult to locate accurately on the ground, 
Perhaps the most important mapping function provided by air photographs in