The sampling error for the total cubic-foot com- 
modity drain estimate was +£1.8 percent, as shown 
by the following tabulation: 
Error of cubic- 
foot estimates 
Product: (percent) 
Sa wilog siecle eae ck mic tee eee ea 25 
Bulpwood=t2s ee ie ne ee ae 2D 
NEES oot at telat fe tel eg Sg eon 5.3 
Polesrand: piling =2] Seis eas awe ee 6.3 
FLEW CrOSS?: Gessner = aU cen ree eae 16.4 
re WOO Casati eae 6.1 
(OYA NCS ieee eee eae Se mal a pee 4.4 
Alle productss2= See ese ea 1.8 
This indicates the chances are two out of three 
that the actual commodity drain was within 1.8 per- 
cent of the estimated. Sampling errors shown apply 
only to State totals. As the totals are broken down 
by counties and species groups, their reliability 
diminishes. 
The sampling error was computed only for cubic- 
foot commodity drain. However, the reliability would 
be slightly higher for board-foot commodity drain 
and approximately the same for standard-cord com- 
modity drain. 
The sampling error in the production estimate 
would be very low, since a complete canvass was 
made except in the case of fuel wood, fence posts, 
and farm timbers. Computation of the production 
estimate was mainly a matter of combining indi- 
vidual reports to obtain county and State totals. 
Public Land Ownership 
Information on the forest area and timber volume 
in Federal, State, county, and municipal ownership 
was obtained in the following manner. The area 
under Federal jurisdiction was obtained from super- 
vising agencies. Various Florida State agencies pro- 
vided the figures for forests, parks, and other State- 
owned lands. County and municipal ownerships were 
obtained at county courthouses and city halls. In 
general the boundaries of these tracts were outlined 
on the aerial photographs or Soil Conservation 
Service maps, and dot counts were made to determine 
the acreage of forest and nonforest land. Forest 
plots were classified by forest type and stand class 
in each publicly owned area, thus giving the area by 
these classifications. Average volumes per acre by 
type and stand-size class, derived from survey unit 
summaries, were then applied to obtain volumes. 
Definitions of Terms Used 
Land-Use Classes 
Forest land area—Includes (a) lands which are at 
least 5 percent stocked with trees of any size and 
capable of producing saw timber or other wood 
products, and (b) lands from which the trees de- 
scribed in (a) have been removed to less than 5- 
percent stocking but which have not been developed 
for other use, subdivided into the following classes: 
1. Commercial—Forest land which is (a) pro- 
ducing, or physically capable of producing, 
usable crops of wood (usually saw timber), 
(b) economically available now or in the 
future, and (c) not withdrawn from timber 
utilization. 
with- 
drawn from timber utilization through statute, 
2. Noncommercial—Forest land (a) 
ordinance, or administrative order, but which 
otherwise qualifies as commercial forest land 
and (b) incapable of yielding wood products 
(usually saw timber) because of adverse site 
conditions, or so physically inaccessible as to 
be unavailable economically in the foreseeable 
future. 
Nonforest land—Land that does not qualify as 
forest land, subdivided as follows: 
1. Active agriculture—Land under cultivation 
or in pasture, including farmyards and work 
lots. 
2. Idle agriculture—Land previously cultivated 
or pastured but now idle or abandoned and 
having less than a 5-percent stocking of trees. 
Oo 
. Marsh—Low, wet areas characterized by a 
heavy growth of grass and reeds and -an 
absence of timber. 
4. Sand dunes and beaches—Nonforested sand 
dunes and coastal beaches. 
5. Urban and 
residential and industrial suburban areas, 
schoolyards, cemeteries, roads, railroads, power 
lines, and other rights-of-way. 
other areas—Includes towns, 
6. Water—Includes lakes, bays, and _ estuaries 
over 40 acres in size and streams, canals, 
and sloughs at least one-eighth of a mile in 
width which are classed as “inland water” 
by the Bureau of the Census. Smaller lakes 
and ponds between | acre and 40 acres in size, 
54 Forest Resource Report No. 6, U. S. Department of Agriculture 
