A BARK BEETLE. 1 27 



for egg-laying, but in these cases it is usual to find the upper 

 branches passed over unless the heap is in shade. 



Attacks by the beetle may be detected by examining the axils 

 of dead twigs or branches where the workings of the insect may 

 be shown by the presence of fine bore dust. 



This investigation adds to the repeatedly emphasised need of 

 burning the litter of brushwood now lying scattered over the 

 country. It is quite conceivable that Cryphalus abietis might 

 become an additional serious insect pest, especially dangerous 

 to young and newly-formed plantations. M. 



19. The Measurement of Timber. 



{With Plate.) 



By John Cape, Statistician, Board of Trade, Timber Supply 



Department, Scotland. 



Since the publication of the report of the Sub-Committee of 

 the Reconstruction Committee appointed by the Government, 

 all interested in forestry are now looking forward to energetic 

 action on the part of the State in the immediate future. In all 

 probability the present year will see the opening of the era of 

 scientific forestry in our country. In the above report one of 

 the duties assigned to the Commission, which the Sub-Committee 

 recommend should be set up, is the " Collection and Prepara- 

 tion of Statistics relating to Forestry." In view of this, the 

 time is surely ripe for the considering of a more satisfactory 

 method of timber measurement than that of the present 

 " Quarter-Girth System." 



Probably about two centuries have elapsed since Hoppus 

 first issued his book on timber measurements, based on the 

 quarter-girth measurement. Since then the system has become 

 universally used by foresters and timber merchants in our 

 country. The quarter-girth measurement is easily obtained, 

 and by referring to the Hoppus tables the contents can be 

 readily found. This has probably been the main reason for 

 the continued use of the system, which has the great dis- 

 advantage of being inaccurate. A closer examination of the 

 method adopted will reveal the inaccuracy referred to : — 



Formula = V = M£_ 

 144 



V = Volume g = the girth or circumference. 



