Periodical Literature 755 



stem diameter the error becomes larger, and with increasing top 

 diameter also. Differences in spruce vary fromO to— 2.5 per cent 

 for a 20 cm b.h.d. and 12 cm top diameter, and down to — 8.5 per 

 cent for a 60 cw b.h.d. and 42 cm top diameter. The butt section 

 with its root collar influences especially the higher result of the 

 sectioning method. The different species show differences in this 

 comparison: the ftdl-bodied fir compared with the spruce shows a 

 more rapid increase of volume based on middle diameter, still more 

 so the beech, so that, e.g., for the 18 cm top diameter the latter 

 volume may be even larger than that obtained by sectioning. 



To avoid practical difficulties in the use of the tables, these, 

 instead of giving the volumes determined by sectioning, bring the 

 assortment volimies determined by middle diameter and length 

 percentically to the timberwood volimie; but the basic timber- 

 wood volimies are those derived from sectioning. 



To gain an insight into results when a long piece is cut into 

 shorter pieces and measiu^ed by middle diameters, a table shows 

 the percentic relation between the measurements by 2 w section- 

 ing and by 6 w sections for the various top diameters and breast 

 high diameters. This shows differences of 1.5 to 8.5 per cent for 

 spruce (6 m measurement below 2 m sectioning), for fir between 

 1 and 8 per cent; for beech between +1.3 and —4.5 per cent. 



The complete tables for single stems then are constructed, 

 with the following headings, in columns: colvmin 1 gives b.h.d. 

 and diameters at 5 m corresponding to different height classes in 

 column 2; column 3 gives timberwood contents of stem for each 

 height class; columns 4 to 9 give in bold face type, in single line, 

 the assortment per cents for different top diameters and under- 

 neath in ordinary type their actual voliunes for each height class ; 

 columns 10 to 16 give lengths and middle diameters of assortments 

 related to top diameters and corresponding to height classes; the 

 middle diameters are given only for the highest and lowest height 

 class, the differences being so small that the intermediate figures 

 can be readily interpolated; the last column gives the length of 

 timberwood, the useful portion, or merchantable length as a 

 per cent of total height. Certain portions of the stem, varying 

 from 4 to 8 m in length for various top diameters, had to be neg- 

 lected, e.g., in the 34 cm class of spruce no entry is made for the 

 32 cm top assortment, because it is too short. 



An example of the use of the table may make the arrangement 



