— 351 — 
tulip-tree, hickory, sycamore, and other species must be deferred until 
more measurements are secured in this region. It is realized that the 
number of black and white oak trees is small, but it is believed that the 
figures are reliable for the area covered by our map. 
Stem ANALYSIS 
For the benefit of those who are not familiar with the field measure- 
ments taken on an individual felled tree, a stem analysis blank such as was 
used is reproduced on page 352, filled out as it was in the field by a party 
of three men. Two men make the required measurements for each section 
of the tree as sawn by the choppers, and a third makes the record. The 
diameter at 41%4 feet above the ground (D.B.H.) can be taken with 
calipers before felling, or measured with a 414 foot stick held on the bole 
of the tree after felling. 
It will be seen that this sheet contains all of the data necessary to 
a calculation of the growth of the tree in height, diameter, and volume, 
so the rest of the work can be done in the office. We have also the 
growth at different ages as shown at different heights above the ground. 
Since we know the diameter inside the bark and the length of each sec- 
tion, we have all the data needed to scale the logs by any log rule or to 
compute in cubic feet the volume of the separate logs, stump, or top. It 
will be noticed that the fifth section of this tree, left in the woods on 
account of crook, had a length of 12 feet and diameters at the ends inside 
the bark of 16.3 and 12.9 inches respectively, and that it scaled 61 board 
feet, and measured 9.84 cubic feet by the Smalian formula for com- 
puting volumes. By adding together the contents of all the unused pieces 
for the whole number of trees analyzed, a very reliable discount or “cull 
factor” for crook or rot can be obtained for any species, and this can be 
applied to the total estimate for that species. 
The procedure in the office is as follows, and Graphs I (p. 372), III, 
IV, V, and VI illustrate some of the steps taken. 
1. Separate the blanks into classes based on their D. B. H. (diameter 
breast-high) ; for example, putting 10.6-inch trees into the 11-inch class, 
10.5-inch trees into the 10-inch class. 
2. Make curves of height and D. I. B. (diameter inside bark) for 
each D. B. H. class represented, plotting D. I. B. at the top of each sec- 
tion as recorded, including the stump. 
3. From the curves thus plotted, read off sets of D. I. B. tables for 
logs at 8, 10, 12, 14, etc., feet above an average stump height of 2 feet. 
4. Harmonize the last readings by making curves for each 2- or 4- 
foot section, based on diameters breast-high. Read off for final taper-table 
(see Table XII, App.), giving the D. 1. B. at different heights above the 
