Siskiyou and Cascade mountains of southwestern Oregon are occupied by
a complex mix of forest types. Forests near the coast
by conifers in the upper portion of the
overstory and hardwoods in the lower portion of the overstory,
while forests nearer the Cascades are dominated by conifers,
with fewer hardwoods. There are relatively few pure stands
of any single species. Because conifers are the commercially
important species, these forests are often lumped together
as “mixed-conifer” forests.
Elevation, distance from the ocean, fire history,
and past management practices all influence these forests.
Near the coast, Douglas-fir and tanoak are the most important species. Golden
chinkapin, Pacific madrone, and canyon live oak are secondary
hardwoods, while sugar
pine, ponderosa pine, and incense-cedar are secondary conifers. Port-Orford-cedar and bigleaf maple occur on
while Jeffrey pine is common on serpentine soils (high
in magnesium). With increasing elevation, hardwoods
become less common, and grand fir and white fir join the mix of conifers.
Near the Cascades, forests
are dominated by mixed stands of Douglas-fir, ponderosa
pine, sugar pine,
incense-cedar, and white fir. This is the
northern-most extension of the mixed-conifer forests that dominate the Sierra
Nevada Mountains of California. Throughout the mixed-conifer
forests, understories are sparse and shrubby with lots
Climate: Climates range from cool and moist
near the coast to hot and dry in the interior. Complex
topography creates a variety of microclimates
supports such diverse forests.