i io transactions of royal scottish arboricultural society. 



Observation on Timber Measurement Suggestion. 



This basis for the computation of standing timber in mass 

 has a world-wide use. The practitioner in France uses it 

 extensively, as also does the "timber cruiser" in the Douglas 

 fir forests of the Pacific Coast. Where accurate and reliable 

 Volume Tariffs are not available, a wider use of this type 

 of table is highly desirable. Thornton T. Munger of the 

 U.S.F.S., in explaining the use of this theoretic method, 

 says : — 



" One type of table used by experienced cruisers on the 

 Pacific Coast is based on d.i.b. above the root swell on 

 merchantable height, and on the rate of taper per log. It 

 is a theoretic table in that it is prepared in the office merely 

 by assuming the required set of diameters and height, and a 

 series of tapers, and then applying the corresponding scale 

 (volume in feet, Board Measure) for each log in the tree. It 

 presupposes, however, a uniform taper throughout the length 

 of the merchantable stem, and this is not true to life 

 usually ; hence the table is theoretically slightly off. A table 

 like this has very great advantages. It is a universal table 

 in a sense, in that one table will do for all species. Its 

 cost of construction is almost nothing. . . . However, since it is 

 based on three variables, it would complicate tallying. ... It also 

 requires the exercise of nice judgment. ... In short, a table of 

 this kind cannot well be fitted in with our (U.S.F.S.) established 

 methods of timber surveys." 



A type of table which is widely used in Western and Central 

 France is based on circumference breast-high, the merchantable 

 tree length and taper. 



" Experiments made on a large number of trees after felling 

 have shown that the circumference taken at 150 metres (height 

 of a man breast-high) from the ground, and rounded off to tens, 

 must be reduced by the taper of from 10 per cent, to 25 per cent, 

 to obtain the mean circumference at the middle point of the 

 merchantable stem. The following proportions have been 

 developed : — 



"A. 10 per cent, to 12 per cent, for forest-grown oak • 

 beech; ash; elm; hornbeam; lime; sycamore; 

 plane ; birch ; aspen ; alder. 

 " B. 15 per cent, in certain special cases. 



