scale of photographs. On larger scale it was for height 5 meters, crown 
closure 2 0%, crown diameter 5m, volume in three classes. On smaller 
scales the limit for height was 10 meters, crown closure in three classes 
and three volume classes. 
Aerial photo-interpretation proved very useful in delineating 
areas of various resource categories. Areas such as blanks and degraded 
type of forests not contributing any growing stock could be separated 
easily on 1:40,000 scale, TIWARI ( 10 ). Delineation into height and 
crown closure classes indicated various categories of existing resources. 
One of the main useful purposes was for volume class stratification a 
basic parameter used in designing of forest inventories. This was even 
attempted down to scales of 1:60,000 for East Godavary Survey by V.K. 
Seth and M.S. Tomar ( 6 ) with significant results. However as a 
general experience volume class stratification on scales larger than 
1:20, 000 could be done easily with sufficient accuracy, TIWARI ( 8 ) „ 
One of the objective method where the stratification into volume classes 
could be done based on forest type with photo height and crown closure 
on 1:40, 000 scale photographs through pilot survey was done by TIWARI 
( 10 ) for Karimnagar forest resources survey. Photo stratification into 
height and crown closure classes was made and volume per unit area in 
each of the types was measured on the ground on predetermined sample 
plots. These types were then grouped into three volume classes on the 
basis of mean volume and variation by Duncan's multiple range test and 
an objective basis was developed for rest of the area whereby the volume 
class could be assigned by recognition of forest type. When applied 
for broad regional area the stratification was significant and gave saving 
in cost and time. 
TOMAR and MASLEKAR ( 13 ) have given a comprehensive 
classification system to be adopted for forest type classification for 
resources survey by photo-interpretation techniques. Their system is 
mainly based on their experience in Pre-investment Survey of Forest 
Resources where in mostly medium to small scales were used. One of 
the main draw backs of the system is that they have used undue weight 
to the scale of the photographs and recognition possibilities of various 
parameters which may overshadow the entire objectives of the survey. 
Aerial photographs are tools to achieve a classification and any such 
system which is based on tools cannot serve the purpose and be a 
standard. Further they do not distinguish between various intensities of 
resource survey and therefore are one sided approach. It is well to be 
seen that it is very difficult to make a standard classification as the 
objectives of the survey are a prime consideration which differ from 
survey to survey. Any attempt to generalize may not cater to all the 
requirements. However the approach and broad categories applicable to 
Indian conditions can be given which may serve the purpose in the 
initial stage and later on the inventory designer may give final shape to 
the classification to be adopted in a particular survey. To this end in 
view, the methodology adopted in Pre-investment Survey organisation has 
been a sound one. 
Wherever the important species could be recognised, they were 
separated out and on larger scales division into percentage classes was 
also given.