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surveys for the purpose of improvement of the technology of evaluation work has 
begun. Large-scaled survey with the aid of helicopter survey of test sites with 
the simultaneous use of two cameras allows one to obtain data about the 
characteristics of vegetation with high accuracy by direct measurement and on 
the base of interconnections between estimation interpretation indices. Some 
indices, like heights of trees, diameters of crowns, and their lengths have 
been measured on the basis of aerial photos even with higher accuracy, than 
in the case of ground experimental work. 
The combination of large-scaled and medium-scaled survey allows 
one to improve the process and to increase the accuracy, and at the same 
time to decrease the labour - consuming character of ground work. 
In the USSR the surveying materials and aerial methods are used 
for the investigation of the health condition of forests, especially for the 
purpose of discovering damage to vegetation by pests, disease and so on. 
False color multispectral films have appeared to be the most promising for 
this purpose, as they allow not only the detection of damaged vegetation and 
trees but to classify vegetation in accordance with the degree of damage. 
During the last years some original investigations were carried out regarding 
the identification, using false color multispectral aerial materials (SN-6M) 
of the degree of damage to vegetation due to air pollution and industrial 
gases or vegetation damage due to entomological pests. 
For example, studying aerial photos with a scale 1:3000 and 
1:5000, four degrees of vital activity of trees were readily identified: 
good trees, slightly damaged trees, greatly damaged trees and dead trees in 
the growing cover, damaged by industrial emmissions [9]. 
The investigations in the zone of expanse of Siberian bombyx 
with the aid of aerial photos (scale 1:3500 u 1:3500) showed that it is quite 
possible by means of interpretation to identify the damaged vegetation and 
estimate the degree of their damage (the error is ± 7%). In addition, on the 
basis of photos of both the scales, the degree of damage of vegetation was 
estimated with high accuracy and there followed the classification into five 
groups. For the detailed estimation of trees, large-scaled photos appeared 
to be more promising. 
The materials of aerial survey find their application in 
mapping of forest soils and types of conditions of forest sites, based on the 
landscape method, taking into account the relations of different types of 
soils and conditions of forest site to the certain forms of relief, and 
complex of direct and indirect indication [2, 12]. 
The modern level of the theory of forest estimation interpret 
ation, the development of aerial methods and technical cybernetics can be 
the basis for future evolution of the measuring interpretation of aerial 
photograph and automatization of main processes of interpretation. 
For the purpose of increasing the objectivity and maintaining 
the quantity indicators of interpretation, microphotogrammetric methods can 
be quite progressive.