such cases crown diameter measurements are not reliable due to various
factors. Better results could be obtained in coniferous forests of
Himalayas and with Sal and Teak species provided suitable scale and
quality of photographs are available. The use of this parameter has
been discouraged in forest type classification in forest inventories.
"Crown Closure Estimations"
The parameter has provided a good substitute for conventional
ground density and has been practiced in India in 2 0% classes. On
medium and large scales it has given good results while on small
scales it had to be limited to three classes only. Usual methods of
dot grid and artificial nomograms provided reliable results. It was
commonly used for forest type delineation and for stand aerial volume
tables. JOSHI ( 4 ) found no significant difference on scales 1:5 000
to 1:2 0000 and photo crown closure and ground density estimations were
within 2 0%. It is experienced that better estimates are obtained on
aerial photographs than from the ground due to better appreciation of
the overall stocking of the crowns on photo. This is true for the bulk
of deciduous forests of India where the forests are varied and irregular
and have a tendency to occur in clusters and poor overall impression is
experienced on the ground.
"Tree Counts"
The experience is in general agreement that counting of trees
on aerial photographs is under estimated. On medium and small scale
photographs the count has never bettered than 6 0 % of the total trees.
On larger scale (larger than 1:10,000) tree counts were successful upto
9 0% (Allapalli teak forests). As a part of resource inventories this
parameter on aerial photos has not been given any importance.
"Tree Aerial Volume Tables"
Poor individual tree species identification possibilities on
panchromatic films have restricted the scope of preparation of tree aerial
volume tables. Of the species which can be identified an attempt has
been made for Teak. The important limitations being the availability of
good quality, larger scale and recent photographs. GUPTA ( 3 ) used
photo height and crown diameter as initial independent variables and
correlated with ground tree volume as dependent variable of 148 teak
trees on 1:10,000 scale. A number of equations between photo height
and ground height, photo height and ground dbh, photo height and ground
volume and also photo crown diameter with ground height, dbh and volume
were tried with initial stratification into converted and non-converted
crop. No significant result with crown diameter was obtained and best
results were obtained with photo height and ground volume. The S.E.
of theregression line ranged from 4% to 24% at 95% probability level
with a correlation coefficient of 0.4 to 0.8. Efforts for the preparation
of tree aerial volume tables of Sal and Chirpine are in progress.
"Stand Aerial Volume Tables"
The scope for the use and preparation of stand aerial volume
tables is better than tree aerial volume tables. GUPTA ( 3 ) attempted