Coast Range in Oregon. Other important broad- 
leaf trees are bigleaf maple, northern black cotton- 
wood, California laurel, and Oregon ash. Bigleaf 
maple occurs more commonly in mixture or as an 
understory tree in conifer stands than in pure 
stands. Northern black cottonwood often forms 
pure stands on the banks of the larger rivers, on 
gravel bars, and on river islands. 
Forest Site Quality 
The distribution of the 26 million acres of com- 
mercial conifer forest land by site-quality classes 
(p. 12), as in table 5, indicates the relative growth 
capacity of the region. The Douglas-fir site classifi- 
cation was applied to all this area except about 
748,000 acres for which the ponderosa pine clas- 
sification was used. The area of Douglas-fir site 
quality I has been greatly reduced by conversion 
of forest lands to nonforest uses, and by deteriora- 
tion of lands that were logged at an early period 
and have been burned frequently. Land of this 
site class occurs principally on the flats and lower 
slopes of the Coast Range of southwestern Wash- 
ington and northwestern Oregon and in the Cas- 
cade Range north of the Cowlitz River. It is rarely 
found in southern Oregon. 
The 28 percent of commercial areas in Douglas- 
fir site class If is common to the Coast Range and 
the lower elevations of the Cascade Range, except 
in southern Oregon. 
Douglas-fir site class III is the most common in 
this region, including areas of the coarser, shallow 
soils on mountain slopes. In western Oregon, 46 
percent of the total commercial conifer forest land 
is in this site class and 39 percent in western 
Washington. | 
Douglas-fir site class IV includes the areas of 
shallow, coarse soil with much exposed rock and 
the drier exposures on the upper slopes of the 
Cascade Range. Little land of this site class is 
found in the Coast Range except in southwestern 
Oregon. 
More than a million acres is of site class V, the 
lowest in the Douglas-fir classification. Class V 
includes the land bordering subalpine and other 
noncommercial areas, gravel bars along streams, 
swampy areas, and exposed rocky ridges. By far 
28 
Tas ie 5.—Land areas in the Douglas-fir region, forest land areas, 
and commercial conifer areas, by site-quality class 1 
Area Area 
Kind of forest and in in com- 
site-quality class Total area forest | mercial 
land _ | conifers 
Commercial conifer: 
Douglas-fir: Acres Percent | Percent | Percent 
Classi ee i= 520, 398 1, 48 1.79 1.99 
Classilie sts aie eae 7, 224, 513 20, 57 24.91 7. 64 
@lasssi ee eee eee 11, 131, 223 31. 69 38. 38 42. 59 
_| 5, 424, 108 15. 44 18. 70 20. 75 
7 
1, 086, 121 3. 09 3.75 4.16 
Totalit: 2 Soe set 25, 386, 363 | 72.27 | 87.53 97. 13 
23, 602 .07 . 08 09 
159, 781 - 45 . 55 61 
378, 357 1.08 1.31 1.45 
169, 111 .48 . 58 . 65 
14, 657 . 04 -05 . 06 
2,217 .O1 OL .O1 
Total'sst2-2 ene 747, 725 2.13 2. 58 2. 87 
Total commercial conifer_|26, 134,088 | 74.40] 90.11 100. 00 
iodgepolepines=2—= = 273, 064 . 78 
Noncommercial rocky_-_---------_- 504, 355 1. 43 
Subalpinet=-2 ee. == see ee eee 1, 162, 882 3. 31 
Oak-madrones tio senate eee ee 364, 299 1.04 
Hardwood eu 556, 712 1.58 
Pine) woodland“: == =2=s2e es 6, 510 .02 
Totalie = a ss eee 2, 867, 822 8.16 9. 89 |=====-== 
Alivforestity pes see = esate aaa 29,001,910 | 82.56 | 100.00 |----___- 
Nonforestitypessssse=- oe 651:259539) | po 75445 | Se | ee 
| 
Granditotalbess=ssosesse= = 35;.127,;449")|| 100003 Sates Ss | Eee 
| 
1 Deforested areas, types 35, 36, and 37, were classified as to site on the 
basis of original type. For definition of site-quality classes see p. 12. 
the greater part of this land is in the Cascade 
Range and in southwestern Oregon. 
Areas of all six of the site classes commonly used 
in classifying ponderosa pine land were found in 
this region. The ponderosa pine land in the 
Douglas-fir region averages about class III, whereas 
that in eastern Oregon and eastern Washington 
averages about class IV. 
Timber Volume 
The quantity, kind, economic availability, and 
ownership of the timber of the Douglas-fir region 
are matters of national as well as regional impor- 
tance. The largest remaining stand of old-growth 
timber in the United States is here. According to 
