d. b. h. or more and of saw-timber character 
(mature stands not of this character are ordinarily 
included in the subalpine type); (24) small, most 
dominants less than 16 inches d. b. h., usually a 
young stand on an old burn. 
Nos. 25 and 26. Lodgepole pine: A forest con- 
taining at least 50 percent, by volume, of lodgepole 
pine or knobcone pine, often pure. ‘The two types 
are determined by the size of 50 percent or more of 
the dominant trees: (25) Large, 12 inches d. b. h. 
and more; (26) small, less than 12 inches. 
Nos. 27 and 28. White fir-larch-Douglas-fir: A 
mixed forest of greatly varied composition, con- 
sisting of two or more of the five species western 
larch, white fir, Douglas-fir, ponderosa pine, and 
lodgepole pine, in which ponderosa pine consti- 
tutes not more than 40 percent of the stand; 
limited to the range of western larch and prevalent 
on north and other cool slopes within the ponderosa 
The two types are determined by the 
size of the trees representing most of the volume: 
(27) Large, 20 inches d. b. h. and more; (28) 
small, less than 20 inches. 
Nos. 29 and 30. White fir: Usually a mixed 
forest within the range of ponderosa pine and sugar 
pine zone. 
pine, containing 50 percent or more, by volume, 
of grand fir or white fir. The two types are deter- 
mined by the size of most of the dominant trees: 
(29) Large, more than 20 inches d. b. h. or 150 years 
in age; (30) small, less than 20 inches or 150 years. 
No. 31. Hardwood: A hardwood forest, either 
pure or mixed, consisting predominately of one 
or more species other than oaks or madrone. 
No. 32. Redwood: A forest containing approxi- 
mately 80 percent or more, by volume, of redwood, 
usually with some Douglas-fir and some Pacific 
madrone, tanoak, and other hardwoods. 
No. 33. Subalpine: A forest at the upper limits 
of tree growth, usually unmerchantable because of 
poor form and small size, the principal components 
being alpine fir, mountain hemlock, Shasta red fir, 
lodgepole pine, whitebark pine, western white 
pine, and alpine larch. 
Miscellaneous Types 
No.. 34. This number was used as a prefix to 
type numbers to denote areas clean cut prior to 
1920 or selectively cut at any time. 
10 
No. 35. Nonrestocked cut-over: An area clean- 
cut prior to 1920 on which less than 10 percent of 
the 13.2-foot squares are stocked, not put to other 
than forest use. 
No. 36. Recent cut-over: An area clean-cut 
since the beginning of 1920, regardless of the status 
of regeneration. 
No. 37. Deforested burn: Land not cut over on 
which the stand has been killed by fire and that 
is less than 10 percent restocked. 
No. 38. Noncommercial rocky: An area of any 
species of timber within the range of commercial 
timber and below the range of the subalpine type 
that is too rocky, too steep, or too sterile to produce 
a stand of commercial size, density, and quality; 
ordinarily the stand averages less than 5,000 board 
feet per acre. 
The scale decided on for type mapping was 1 inch 
to the mile. A larger scale would have led to 
excessive detail and made the cost more than was 
contemplated; a smaller one would not have pro- 
vided sufficient space for the field examiner to 
record data of the desired completeness. Obvi- 
ously, areas only a few acres in extent could not be 
mapped on the adopted scale. It was decided that 
all 40-acre or larger areas of commercial forest 
land—that is, land now bearing or capable of pro- 
ducing forests of commercial character—and agri- 
cultural land should be mapped, but that for non- 
commercial-forest land, barrens, etc., the minimum 
should be several hundred acres. Hardwood types, 
owing to their infrequent occurrence, usually as 
‘‘shoestrings’’ along creek and river bottoms, were 
mapped if occupying areas as large as 20 acres. 
These limits are fixed not absolutely but merely as 
In all cases the field examiner was al- 
If he could con- 
veniently map a farm or a patch of conifer timber 
as small as 20 or 30 acres without slowing down the 
a guide. 
lowed to exercise his judgment. 
work he was at liberty to do so; if he was mapping 
an area low in values and difficult of access he was 
allowed to generalize more than if mapping an 
area of high values and easy access. 
Classifications 
Ownership Classes 
Separation of forest type and volume data accord- 
ing to ownership was considered particularly im- 
