136 



The exploitable age.— The manner in which the exploit- 

 able age has been calculated, and the facts on which the 

 calculation has been based, should be stated. As already- 

 indicated these facts or considerations relate to the products 

 required, the object with which the forest should be worked, 

 the rate of growth, the prices realised and the net value of 

 the trees standing in the forest. 



Erample — .It has been stated that the object with which this forest should be 

 worked is to supplj' fuel and timber for the neighbouring population, and it has been 

 decided that this end may best be accomplished under the coppice method of treat- 

 ment. It has been shown that the fuel billets required should not exceed 4 inches in 

 diameter, as, if larger, it becomes necessary to split them, and they bring in a lower 

 nett price. From the rate of growth of the coppice it is known that this size is 

 attained in about 12 years. It is, therefore, proposed to exploit the forest on a 

 rotation of 12 years. As regards the standards, we have seen that trees of 1 foot in 

 diameter furnish the required small timber, and that they attain this size in about 

 60 years. It is, therefore, proposed to retain a certain number of the standards of 

 each coupe for five rotations of the coppice. 



General scheme of working and calculation of the possibility. — 

 The calculation of the possibility should be based on the 

 analysis of the crops, or, where an enumeration survey has 

 been made, of the standing stock in the forest. 



The general scheme of working and the method of cal- 

 culation having been explained and the possibility deter- 

 mined, the condition of the stock as regards its suflB.ciency 

 or insufficiency, the arrangement of the age-classes and so 

 forth, should be discussed. The length of the preparatory 

 period, during which it may be necessary to reconstitute the 

 crop or lead it on to normal condition, should also be 

 explained. 



^a!(»»!^(e.— It is proposed to exploit the principal species, teak, by the selection 

 method ; and the length of the felling rotation adopted is 20 years or half the period 

 (40 years) required for a tree of the lowest dimensions of Class II to attain the lowest 

 dimensions of Class I. The valuation surveys show that the age<classes are a& 

 follows : — 



Class I 65,871 trees. 



..II 87,846 „ 



,, III 63,000 „ 



., IV 927,000 „ 



It may be assumed that, as there are 87,846 trees of the 2nd Class, the greater 

 proportion of which will attain exploitable dimensions in the course of 40 yeais, the 

 number of trees which will become exploitable each year is something less than 87,846-^ 

 40 or about 2,000 trees. Under a telling rotation of 20 years, the normal exploitable 

 stock on the ground should therefore be :— 



In the area first felled over 20 years ago ■ ^'^- X 20. 

 » next „ 19 years ago -^^ x 19. 



etc., etc., etc. 



I i 1 2,oco , 



» last „ 1 year ago —^ x 1. 



The normal exploitable stock would, therefore, be 100 ^ (20 -|- 19 + &c. + 1) sa 

 21,000 trees. 



