January, 1910.] 



&3 



Tim bers. 



class, trees above 1£ feet and up to 2 feet 

 in diameter as 11 class, and trees above 

 2 feet in diameter as I class. 



It thus comes about that 1 class trees 

 are loosely referred to as being either 

 above 6 feet in girth or above 2 feet in 

 diameter, as if these measurements were 

 synonymous. An instance in point oc- 

 curred a few years ago in an important 

 working-plan. The enumerations were 

 done with callipers graduated for 6 

 inch diameter classes, and the results 

 obtained were treated as girth classes 

 and the prescriptions made accordingly. 

 Owing to this, trees in the first coupe 

 above 6 feet in girth which were found 

 available for felling were 2,000 more 

 than the number expected,, for the 

 change from diameter to girth classes 

 really brought more than one-sixth of 

 the trees shown in the enumerations as 

 II class according to diameters into the 

 I class according to girths, i.e., above 

 6 feet in girth. 



Again, the classes mentioned above 

 have practically become, throughout 

 India, standard classes of measurement, 

 and it only remains for it to be decided 

 whether girth classes or diameter classes 

 are to be adopted for the future. Thus, 

 almost all forest officers if asked what a 



I class tree was, would say it was a tree 

 measuring over 6 feet in girth or over 2 

 feet in diameter; some would say the 

 one, some the other, and some, speaking 

 loosely, would speak of the two as 

 synonymous. Thus, a class I tree is 

 practically a standard size, differing 

 only within the above limits. This 

 being so, it is very confusing to find 

 that in some cases trees of other sizes 

 are called I class, and so on. For an 

 instance we refer to page 571 of the 

 October number, where the classes 

 adopted are quite different. Any one 

 after reading the article on this page 

 would, on turning to page 588 of the 

 same number, be puzzled to know what 

 is meant by a III class tree in the last 

 sentence of para 11. 



It is therefore, we consider, most 

 advisable that definite standard classes 

 should be fixed so that it will always be 

 known what is meant by a I class tree, 



II class, and so on. In our opinion girth 

 classes are the most suitable, for the 

 sections of trees are seldom circular, and 

 it is a matter of some difficulty to ascer- 

 tain the exact average diameter of a 

 tree, whereas the exact girth can always 

 be easily ascertained. By this we do 

 not mean that all measurements of trees 

 for marking, etc., should be done by 

 tape. It is easy to have callipers gradu- 

 ated to correspond to the diameters of 

 the 18 inches girth classes, and it is 



usual in practice when using callipers 

 to measure each tree in two directions 

 at right angles. We have found it 

 quite accurate, if it is found that a tree, 

 measured in both directions, falls to the 

 same class, to record it as belonging to 

 that class, but when the measurement 

 in one direction locates a tree in one 

 class, the measurement in the other in 

 another class, we found the simplest way 

 to decide the right class was by girth 

 measurement with a tape. We recom- 

 mend that the girth classes given above 

 be now officially adopted as standard 

 classes, so that in future there will be no 

 doubt as to what is meant by a I class 

 tree, II class, and so on, and as these 

 clasess are already generally known 

 and used, it would be simpler to adopt 

 them than to lay down a revised scale 

 of classes together. 



Of course we recognise the fact that 

 for many working-plans and other pur- 

 poses, the standard classes would not be 

 sufficient, as it is often necessary to dis- 

 criminate between the sizes of trees 

 above 6 feet in girth and to differentiate 

 in more detail between smaller trees. 

 For the latter, subdivisions of the 

 standard classes will generally suffice, 

 but for all other divisions from the 

 standard classes we recommend the 

 adoption of letters to indicate that the 

 class referred to is a special one. Thus.in 

 cases where a minimum exploitable size 

 of above 7| girth is adopted, the class 

 above 1\ feet in girth might conveniently 

 be termed M. class, meaning mature, or 

 by any other appropriate letter. Any 

 officer coming across the mention of an 

 M. class tree for the first time, would at 

 once enquire what it meant and no con- 

 fusion would arise. 



The question as to the height at which 

 the girth measurements should be taken 

 is more complicated, for on account of 

 some species developing large buttresses, 

 they cannot be measured at the usual 

 breast height which is generally taken 

 to be 4| feet above the ground. For 

 practical purposes it will probably be 

 sufficient for the girths to be taken as 

 they are now at breast height where 

 there are no buttresses, and as near 

 above that as the buttresses will allow, if 

 there are no buttresses, except when the 

 buttressed portion is utilised, in which 

 case a correcting factor might possibly 

 be adopted. This matter is one on which 

 some enquiry is necessary before stand- 

 ard rules can be decided on. 



At present in India, so far as we are 

 aware, there are no height classes in 

 general use, and it may be argued that as 

 there are so many different species to 

 be dealt with, it would not be of much 



