862 JOURNAL Ol- FORESTRY 



Another coniniendable feature of this new type of xylometer is its 

 portabihty. A tank 8 feet long, 2>^ feet wide, and 2 feet high weighs 

 only about 140 pounds. The ease with which such an instrument may 

 be transported, because of its light weight and practical form, is a dis- 

 tinct advantage when the work is done in the forest. In many cases it 

 is easier and more economical to transport the xylometer than the wood 

 material. 



The degree of accuracy which may be attained by using a xylometer 

 recommends this instrument for most scientific investigations requiring 

 an accurate determination of volume. The exclusive use of a xylom- 

 eter is not always recommendable. In many cases it may be satis- 

 factory to use it only intermittently as a check on other less accurate 

 but more practical methods. The following tabulation gives the results 

 obtained by three different methods of computing the contents of seven 

 representative trees selected from a large number comprised in a tree 

 analysis study: 



Tree number Schiffel's formula Smalian'si formula Xylometer^ Xylometer' 



cubic feet cubic feet cubic feet cubic feet 



1 24.70 23.85 24.78 25.05 



2 53-53 55.18 56.95 73-72 



3 4770 48.53 50.70 60.50 



4 16.93 17.07 17-70 21. J2 



5 67.73 81.97 94.91 112. ?6 



6 10.22 11.68 11.49 14.56 



7 36.72 37.50 38.12 40.90 



x\ comparison of the above results shows that the volume obtained by 

 Schiffel's formula is only 87 per cent and that of Smalian's formula 

 only 93.5 per cent of that ascertained by the use of the xylometer in 

 determining the volume of the stem only. A further comparison of 

 columns four and five shows that the branches comprise on an average 

 18.8 per cent of the total tree volume, ranging from i.i per cent in tree 

 number one, which was a suppressed white pine with a very small 

 crown, to 22.8 per cent in tree number two, which was a dominant 

 white pine with high and wide crown. 



Tree number one — a white pine — was manufactured into shingles. 

 It yielded 603 shingles (4x21 inches), which displaced 11.86 cubic 

 feet of water, showing that only 47.3 per cent of the wood originally 

 in the tree remained in the finished product. Tree number seven — a 

 chestnut — was also manufactured into shingles. It produced 908 shin- 

 gles (4x21 inches), which displaced 18.97 cubic feet of water, indi- 



^ Stem only. Sections 4 feet in length. 



' Stem only. 



^ Stem and branches. 



