XC L. MATTSSON. 
breast-high and the cylinder with the same diameter breast-high and the same 
height as the total stem. In the same manner we can get a similar factor 
relating to the part of the stem under breast-height. Then the sum of these 
two factors is the breast-high form-factor generally used. Figures worked out 
in such a manner are to be found in table 31, page 915. 
In quite the same way form-factors for the bark can be made out relating 
to the cylinder inside the bark. The latter, when divided by the former, 
finally gives bark in :percentages of the wood inside it. Such values for 
different form-classes and bark-quotients at the middle of the stem are 
to be found in table 33, page 918. These figures are valid for stems with a bark- 
percentage breast-high of 10 percentages. 
As is to be seen from table 33 the bark from a stem of the form-class 
0.60 and the bark-quotient at the middle of the stem o.6o, makes nearly 21 
percentages of the wood inside it. For the same stem, however, the relation 
between the area inside and outside the bark at breast height is 1007: 1102 
or 100: 121. That is to say, the area of the bark at breast-height is in the 
same ratio to the area of the wood as the volume of the bark to the volume 
of the wood. For such a stem, therefore, the form-factors made out for the 
wood-stem are also applicable to the stem including the bark. 
