30 
Indian Forest Records. 
[VOL. III. 
Girdlin' 
Yield liow fixed. 
working-plan is divided into a number of “ sub-periods ” accordingly. 
These sub-periods vary from 4 to 8 years, but are usually 5 or 6 years, in 
duration. 
Details of periods and sub-periods in the various working-plans 
will be found in Appendices I and III. 
When teak trees are selected for felling they are at the same time 
“ girdled,” or ringed all round down to the heart- 
wood, the object being to kill them and render 
the timber sufficiently buoyant for floating purposes. Girdling also has 
the effect of seasoning the timber. Actual felling does not commence 
for 3 years after girdling. In the teak working-plans of Burma, there¬ 
fore, instead of annual “felling statements” we find “sub-periodic 
girdling statements.” 
2. Estimates of Yield and Results of Working. 
In all the working-plans where the selection system is prescribed, the 
yield is estimated by the number of trees of ex¬ 
ploitable size which may be girdled in each sub¬ 
period, the average annual yield being also stated. The sub-periodic 
areas, in which alone girdlings may be carried out in the corre¬ 
sponding sub-period, are also defined. The actual selection of trees for 
girdling is carried out under sylvicultural rules. 
As a general rule the working-plans lay down that the sub-periodic 
yield by number of trees is to be regarded as strictly limiting the 
number of trees to be girdled during the sub-period, any excess girdling 
requiring special sanction. In the case of an under-estimate such a 
rigid fixing of the possibility, however, is apt to result in the leaving 
of over-mature trees which ought sylviculturally to be removed, and 
hence in some of the more recent working-plans the estimate of the 
yield is rightly regarded merely as a guide, and may be exceeded in 
moderation without special sanction, provided the necessary sylvi¬ 
cultural rules have been complied with. 
In Appendix IV will be found a summary of figures, compiled from 
statistics regarding working-plans and Control forms, relating to 
yield and outturn. yield and outturn. 
With regard to statistics relating to the results of working, it may be 
said generally that the figures relating to the 
Accuracy of figures. number of trees girdled (co lumn 8) are 
correct, as they are compiled from statements prepared by girdling 
officers. The figures relating to the number of logs and volume of 
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