84 MEASUREMENT OF FELLED TREES. 



(1) Shape and nature of the pieces ; thick, smooth, and 



straight pieces give more solid contents than thin, hent, 

 uneven pieces. 



(2) Length of pieces; short pieces pack better than long 



ones, hence they give a higher percentage of solid 

 contents. 



(8) Method of stacking; careful stacking causes the per- 

 centage of solid wood to be considerably increased. 



It is evident from the above remarks that no absolutely 

 average data can be given. By way of illustration, it may 

 be mentioned that the coefficients which are officially re- 

 cognized in Hesse-Darmstadt as representing averages, are 

 the following : 



Split firewood . . . ' . , . = ? 

 Round firewood billets under 5" diameter = '6 

 Root and stump wood . . . . = '5 

 Fagot wood stacked (not bound) . . = :2 



That is to say, 100 cubic feet of stacked split firewood 

 contain 70 cubic feet of stolid wood and 30 cubic feet of air, etc. 



3. Volume of the Bark. 



In many cases it is desirable to ascertain the volume of the 

 bark, especially when it is sold separately, as in the case of 

 tanning bark. This can be done stereometrically or xylo- 

 metrically. In the former case the pieces of wood are 

 measured before and after barking, the difference giving the 

 volume of the bark. If a xylometer is used, the bark can 

 be measured separately, or the pieces of wood are measured 

 before and after barking. 



According to species, age, and locality, the bark comprises 

 from 6 to 20 per cent, of the total volume. Schwappach found 

 on a limited number of trees the following results : 



Oak . . . = 15 20J 



Ash . . . = 1214 

 Elm . . . - 911 



Birch . . . = 1317 



Alder . . = 1619 



Lime . . . = 1619 



Aspen . . = 913 



Scotch Pine . . = 1016 



