values in the stand tables, particularly between the horizontal 
values, change rapidly, interpolation is best accomplished from 
& curve. 
It should be clearly understood that the percentages given in 
the stand tables do not hold for any stands that are not normally 
stocked. That too absolute a reliance should not be placed on 
the tables even in normal stands is suggested by the fact that 
the tables give data for 2-inch intervals only. 
DEFINITION AND EXPLANATION OF TERMS. USED 
GENERAL TERMS. 
Age.—The average age of the dominant trees in a stand is 
taken as the age of the stand. Average age is based on ring 
counts made on several dominant trees covering a good range of 
sizes. 
Ring counts may be made on stumps or by taking increment 
cores at breastheight. In figuring total age, 3 years must be 
added to the breastheight age of loblolly, shortleaf, and slash 
and 7 years to that of longleaf. If age determinations are made 
at a stump height of 1 foot, 2 years is added for total age of 
loblolly, shortleaf, and slash and 5 years for total age of longleaf. 
Average diameier, breast high. The breast-high diameter of the 
tree of average basal area. 
Average dominant tree.-—Dominant trees include the codomi- 
nants also. The average dominant is a tree having a basal area 
equal to the average basal area of the dominant stand. 
Cords.—Cords are of 4-foot wood. Converting factors from 
cubic feet to cords are given for trees of different diameters in 
Table 171. 
Diameter class——Each inch-class includes diameters 0.4 inch 
or less below and 0.5 inch or less above the even inch; for example, 
the 9-inch class comprises all trees 8.6 to 9.5 inches, inclusive. 
Height, total—Total height is reckoned to the extreme tip of 
the tallest branch, not simply to the upper limit of utilization. 
One and one-fourth logs —The smallest tree considered in this 
bulletin to have a board-foot volume contains one 1€-foot log to 
the top diameter specified (5 inches inside the bark in the inter- 
national tables, 6 inches in the Scribner tables, and 7 inches in 
the Doyle tables). Since all l-log trees would have the same 
volume, regardless of diameter at breastheight, the shortest trees 
for which volumes are given contain 144 logs. This value is the 
midpoint between 1 and 1} logs; 114 logs is the lower limit of the 
2-log class. Volumes for trees intermediate in log length between 
oe shown in the tables may of course be obtained by interpo- 
ation. 
Site index.—Sites are designated by the height attained on each 
by the average dominant tree in a 50-year-old stand; this height. 
15 
