ESTIMATE BY MEANS OF VOLUME TABLES. 



39 



The follo^Ying table shows the form factors, taken from the 

 Yield Tables in Appendix III., on pages 345 to 379. 



In the case of quarter girth measurements, the form factors may be placed at 

 three-fourths of those for timber in the round. For instance, the form factor 

 for 70 feet high oak would be = •oO x f = ■37. 



In using these tables, it must not be forgotten, that they 

 give the averages of numerous measurements ; hence, they do 

 not give reliable results in calculating the volume of a single 

 tree. Their application should be restricted to the calculation 

 of the volume of a number of trees — in other words, of whole 

 woods — where the differences between the several trees are 

 likely to compensate each other. (See example on pages 60 

 and 61.) 



3. Estimate of Volume hi/ means of J'olume Tables. 



If, instead of giving the form factors only, they are multi- 

 plied by the corresponding heights and basal areas, the 

 volumes of the trees are obtained, which can be arranged into 

 so-called " volume tables." The latter may be defined as tables, 

 which give the volume of single trees arranged according to 

 species, age, diameter and height of tree. 



