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The approach to the selection of the optimum wave 
length range is as follows. Since the large variance of 
the radio-brightness temperatures of the boggy areas is 
caused by the non-uniform wetting, then at the selected 
wavelength the vegetation layer should be transparent or 
semi-transparent in order to screen the soil and the water 
areas of small size. At the same time the terrain resolu 
tion should be not much more than the characteristic size 
of nonuniformities £ . The terrain resolution D depends on 
parameters of the antenna and wavelength. Thus, relation 
ships (3) should be supplemented with the restraint of the 
type I>(A,d) « K a P 
(6) 
where d - is the vector of antenna parameters; 
Kci-is the constant determined by the three-dimen 
sional spectrum of electrophysical heterogeneity 
of the object causing fluctuations of radio 
brightness temperatures. 
Just as in the earlier case selection of polariza 
tion has become biased in favour of the horizontal one not 
only because of the less absorption in the vegetation 
layer but also because of large differences in the radio 
brightness temperatures under the same variation of elect 
rophysical parameters. 
In our opinion, the joint use of the microwave radio- 
metrical and multizonal measurements are highly promising 
in studying forests. One of such problems here is the 
assessment of fire-hazardness of forests. 
From the results of the joint processing of the aerial 
photos and synchronous microwave radiometrical measurements 
we have developed the technique for assessing fire hazard- 
ness of forests. The appropriate ground measurements were 
conducted synchronously which included determination of 
the level of ground water, detailed forest-estimation 
description of the route being investigated and assessment 
of fire hazardness with the use of standard methods. The 
algorithm developed on the basis of the obtained informa 
tion makes it possible to estimate the fire-hazardness