cull trees also include the limbs, in sections 4 feet 
long and at least 4.0 inches in diameter inside bark, 
of sound saw-timber-size hardwoods. Scrub oak and 
noncommercial species such as ironwood, blue beech, 
sassafras, etc., are included in this group. 
Rotten cull trees—Live trees of pole-timber and 
saw-timber sizes that fail to meet regional specifica- 
tions of the proportion of sound volume to total 
volume. 
Palms—All species of Sabal 5.0 inches d.b.h. and 
larger with at least 12 feet of clear stem. All palm 
trees were considered to be free of rotten defect. 
Species Groups 
Softwoods—All of the pines, eastern redcedar, 
Atlantic white-cedar, pond cypress, and baldcypress. 
_ Soft-textured hardwoods—Black and water tupe- 
los, sweetgum, soft maple, magnolia, and sweetbay. 
The other soft-textured hardwoods include cotton- 
wood, willow, basswood, and yellow-poplar. 
Hard-textured hardwoods—All of the oaks, hick- 
ories, ash, river birch, elm, hackberry, and sycamore. 
Volume Estimates 
Board-foot volume—The volume in board feet, 
measured by the International %-inch rule, exclusive 
of defect, of that portion of saw-timber trees of 
softwoods 9.0 inches d.b.h. and larger and hardwood 
trees 11.0 inches d.b.h. and larger, between. the 
stump and the upper limit of merchantability for 
sawlogs. 
Volume in cords—The volume in standard cords 
(including bark) of the sound portion of trees 5.0 
inches d.b.h. and larger, between stump and a 
minimum top-stem diameter of 4.0 inches inside bark, 
and the volume in hardwood limbs, in sections 4 
feet long and at least 4.0 inches in diameter inside 
bark. 
Volume in cubic feet—Same as volume shown 
in cords except bark is not included. 
International %-inch log rule—A rule for esti- 
mating the board-foot volume of 4-foot log sections, 
according to the formula V = 0.905 (0.22D? — 
0.71D). The taper allowance for computing the 
volume in log lengths greater than 4 feet is 0.5 
inch per 4-foot section. Allowance for saw kerf is 
¥%/, inch. 
Standard cord—A stacked pile, 4 x 4 x 8 feet, 
of unpeeled round or split bolts, estimated to contain, 
on the average in Florida, 72 cubic feet of softwoods 
(wood only) or 71 cubic feet of hardwoods (wood 
only). 
Gum Naval Stores Conditions 
Round timber—A minimum of 15 longleaf and 
slash pine trees 9.0 inches d.b.h. or larger per acre 
that have never been worked for naval stores. 
W orking—Longleaf and slash pine trees that are 
now being worked for naval stores. 
1. Front-faced—Turpentine tree species on 
which the front or first face is now being 
worked. 
2. Back-faced—Turpentine tree species. on 
which the front face has been worked out 
and on which a back (second or third, etc.) 
face is being worked. 
Resting—Longleaf and slash pine trees with a 
worked-out front face at least 5 feet high and on 
which back-facing has not been started. 
Abandoned—Longleaf and slash pine trees on 
which faces less than 5 feet high were discontinued. 
Worked-out—Longleaf and slash pine trees on 
which two or more faces at least 5 feet high have 
been worked out and with no possibility of supporting 
another face. 
Stocking 
Stocking is the extent to which growing space is 
effectively utilized by present or potential growing- 
stock trees of commercial species. The number of 
stems present by d.b.h. classes was used as a basis 
for stocking classification. Areas having the minimum 
numbers of trees listed below, either in a single 
diameter class or in combinations, were considered 
fully stocked. 
Minimum number 
trees per acre 
D.b.h. (inches) : 
DoE MONS Wey PROTO EAC iy ANS ee re 800 
4 es BS ee SS a a 600 
Gi ee ae ee ed RS er 450 
Git Ba ew) Se ee Ee a Se ey eee 300 
QS eas EP EAE Ren a ee ee 200 
[PD Pt Re GEE aa II SE) A = SI 150 
DA a A ES aT Rn AES ce 110 
Growth and Drain 
Net annual growth of saw timber—The change 
in net board-foot volume during the calendar year in 
the live saw timber on commercial forest land re- 
sulting from natural causes exclusive of catastrophic 
56 Forest Resource Report No. 6, U. S. Department of Agriculture 
