156 CONSTRUCTION OF STANDARD VOLUME TABLES 



These are, 



Soil, origin, whether sedimentary or residual. 



Depth, rock, physical character, sand, etc. 



Exposure and slope. 



Altitude. 



Forest type. 



Character and density of stand. 

 These items involve considerable repetition and are often omitted, 

 or may be written up for groups of trees. But if the material is to be 

 used for investigations, to determine the effect of site factors on form, 

 each tree analysis should be associated with a complete description 

 covering the points enumerated. 



134. Measurements of the Tree Required for Classification. The 

 measurements of the felled tree must be taken before the logs are 

 removed by skidding. These may be divided according to their pur- 

 pose into those needed to 



1. Classify the tree by dimensions and character. 



2. Obtain the volume of the stem and branches. 



The first class of measurements consists of D.B.H., height of stump, 

 total height, crown and bole. The D.B.H. (§ 125) is the most important 

 measurement taken. This point must be located on the butt log of 

 felled trees, unless the D.B.H. has been taken in advance of felling 

 the tree. To the stump height is added the additional height needed 

 to equal 4| feet, which is measured upon the butt log. If the butt cut 

 is slanting, care is taken to measure from the same point on the log as 

 on the stump, thus reproducing the measurement which would be taken 

 on the standing tree — otherwise a slight error is incurred. The D.B.H. 

 and all other measurements of diameter are taken in two directions, 

 at right angles. This is always possible on the felled trees as shown 

 in Fig. 25. 



The average of these two diameters is obtained and recorded to 

 the nearest iVmch, and is never rounded off to the nearest inch. 



The height of stump is taken not only to obtain D.B.H. on felled 

 trees, but as a basis from which merchantable length and contents 

 is figured (Chapter XII). It is recorded in feet and tenths, or in feet 

 and inches*. Stump height is measured vertically from the root collar 

 or point of contact with the ground, and at the average height of this 

 collar. On side hills, this point occurs half way between the upper 

 and lower sides of the stump. 



The total height of every tree measured for volume should be recorded, 

 whether or not it is to be used as a basis of height classification (§ 137). 

 The most accurate method is to stretch a steel tape from the butt to 

 tip of crown, along the stem, although a pole graduated in feet is some- 



