of Oregon > Douglas-fir Forests
forests are the most extensive in Oregon; they’re also the most important
for timber production. Although Douglas-fir is the dominant forest tree
west of the
crest of the Cascades,
it’s also an important component of eastside forests. West of the Cascades, Douglas-fir
often forms vast, nearly pure stands, a result of both natural conditions and
human management. Common associates include western hemlock (the climax species
for much of this region), western redcedar, noble fir, bigleaf maple, and red
alder (the most common early successional species for
most of this region).
East of the Cascades, common associates include
incense-cedar, sugar pine, western white pine, ponderosa pine, grand fir, white
fir, and western larch, depending on moisture
and stand history. Understories vary from dense to sparse depending on the
availability of moisture, but are generally rich in shrubs and herbs. Douglas-fir
is a long-lived, early- to mid-successional
species. This means that it can colonize recently disturbed sites, but continue
to dominate them for hundreds of years.
Climate: Douglas-fir forests grow under a
wide variety of conditions. The climate of westside Douglas-fir forests ranges
from wet and mild in the north to drier and warmer in the south.
Eastside Douglas-fir forests are drier than those of southwestern Oregon and
have more extreme temperature fluctuations, both daily and seasonally.
Management: Prior to human management, Douglas-fir forests
originated following large disturbances such as fire, landslides, and windstorms,
resulting in a combination of even- and uneven-aged stands. Douglas-fir trees
become commercially valuable around
the age of 30 years. Over most of the west side, timber management practices
such as clearcutting and shelterwood harvests followed by planting and thinning
result in even-aged forests. Rotation lengths
range from 30 years to hundreds of years, depending on management objectives.
In drier areas like southwestern and eastern Oregon, management practices
commonly include individual tree and small
group selection harvests, resulting in uneven-aged stands.
hemlock/Sitka spruce forests urban
mixed conifer forests coast
redwood forests hardwood
pine forests subalpine
larch forests western