6 



3. Measurement of Small Wood. 



The solid contents of toppings and loppings, and of irregular- 

 shaped pieces from stumps and roots, are obtained by the water 

 method (being equal to the quantity of water they displace when 

 submerged) or by the water-method and weighment combined. 

 For the water-method special vessels, called xylometers, may be 

 employed. In the combined system samples of each kind or class 

 of wood are successively weighed and measured by the water- 

 method, and the contents of the entire quantity in each class are 

 then worked out by means of a simple proportion sum. Figures 

 expressing specific gravity cannot be employed, since the specific 

 gravity of wood varies not only according to the amount of mois- 

 ture present, but even in one and the same tree according to the 

 part from which it is derived. 



The most rapid way of measuring small wood on a large scale is 

 to stack it cut up into billets of one and the same length, the 

 width of each stack being equal to the common length of the 

 billets. The contents of a stack will be equal to length x height 

 X common length of the billets. The length of a stack built up 

 on a slope must be measured horizontally. The above formula will 

 give us only stacked contents ; to reduce these to solid contents, we 

 must determine, by the water-method, or by the combined water 

 and weighment method, the exact volume of a sufficiently large 

 number of stacked units, thereby obtaining the ratio between solid 

 contents and stacked contents. To obtain the solid contents of a 

 stack we have then only to multiply the stacked contents by this 

 ratio, which we may hence term a reducing factor. The following 

 figures may be accepted as average reducing factors for converting 

 stacked into solid contents : — 



For split wood .... 0-60 to 0-80 



„ round billets .... 0'50 „ 0'65 



„ small stuff . . , . 0-30 „ 0-45 



„ wood from stumps and roots . 0*30 „ 0"4.0 



In connection with the determination of the solid contents of 



stacked wood it is obvious— 



(a) That the longer the billets are, or the less carefully built 

 up the stacks are, the less will be the solid contents. 

 In careless stacking billets often lie across one another. 



