Volume XXIII - 1992 90th Anniversary Edition
Biodiversity in Red Blanket Canyon
By Steve Mark
Virtually all of the canyons in Crater Lake National Park are worth
exploring. Many contain pinnacles or other interesting geological
formations, but all of them are good hikes. As stream habitats, they
harbor a greater diversity of life than the meadows, nonriparian
forests, or pumice fields. The term biological diversity has been used
to express the variety and variability among living organisms and the
ecological complexes in which they occur. Diversity can be defined as
the number of different items and their relative frequency. These items
are organized at many levels, ranging from complete ecosystems
(ecosystem diversity) to the chemical structures that are the molecular
basis of heredity (genetic diversity).
Between ecosystem and genetic diversity lies species diversity,
which refers to the variety of living organisms on earth. The most
commonly accepted definition of a species is a population of organisms
that can at least potentially breed with one another but that do not
breed with other populations. Species diversity is a function of what
the surrounding habitat allows. Wetlands and streams have long been
known to harbor the greatest species diversity among the various habitat
types. This is particularly evident as one hikes along the streams
within Crater Lake National Park. For example, one could contrast the
stream that originates at Boundary Springs with the adjacent lodgepole
pine (Pinus contorta) forest.
Of all the habitats within Crater Lake National Park, species
diversity is greatest in Red Blanket Canyon. Only a small fraction of
the canyon is within the park's boundaries, but this is an environment
very different from the subalpine, snow-adapted forest of Mountain
hemlock (Tsuga mertsensiana) and true firs (Abies concolor, A.
Iasiocarpa, and the A. magnifica-procera complex) that
dominate so much of the park. The 4200 foot elevation of the park's
southwest corner is suitable for the growth and development of a mixed
conifer forest. Its presence in the vicinity of Red Blanket Canyon was
largely determined before 1900 through historic fire disturbances and
the habitat type common to the Prospect area.
Some of the forest at the lower elevations in the canyon can be
labeled old-growth, the kind of forest which once dominated the area
between the Pacific Ocean and the crest of Oregon's Cascade Range. Exact
ecological definitions for these forests remain elusive, yet several of
their structural components are easily discernable: large live trees,
large snags, large logs on the ground, and large logs in streams.
Greater structural diversity is evident than in younger stands, as
old-growth trees have a much greater range of diameters, tend toward
more heterogeneous spacing, and exhibit greater patchiness with respect
to their understory vegetation.
The upper three miles of Red Blanket Canyon have a different species
composition and function than the heavily logged forests of the lower
Red Blanket drainage and the Prospect Flat area. As an old-growth
forest, the upper canyon also displays differences in the rate and paths
of energy flow. Likewise, it is distinct from stands further downstream
in water and nutrient cycling. Maintenance of a large conifer overstory
is critical to the survival of species not found in the younger forests,
such as the Northern spotted owl (Strix occidentalis caurina) and
the Pacific yew (Taxus brevifolia). These species are fairly
easy to discern and relatively large, characteristics which have been
used as indicators in gauging the health of an increasingly fragmented
life support system.
Red Blanket Canyon is accessible from Prospect or by using the trail
system in Crater Lake National Park south of Highway 62. Most visitors
go east of Prospect on Red Blanket Road to Forest Service Road 6205. The
head of the canyon is roughly four miles up the gravel road, past a gate
which is closed during the winter months. As one proceeds toward the Red
Blanket trailhead located at road's end, several regenerating clearcuts
are periodically apparent near the stream. Roughly two miles short of
the Red Blanket trailhead is a sign marking one end of the Varmint
trail, which climbs through an old-growth forest and up the canyon's
north wall. Lightly used, the Varmint trail allows hikers to see the
last roadless area adjacent to Crater Lake National Park not having
legal wilderness designation.
The southwest corner of the park is encountered within a half mile
of the Red Blanket trailhead. At just over 4,000 feet in elevation, the
corner marker is located in a lush old-growth forest. The trail
straddles the park boundary for its first mile and a quarter, generally
staying above Red Blanket Creek but occasionally beckoning the walker to
explore small tributary drainages on the canyon's north side. The most
prominent stream drains the southwest slope of Union Peak, which is an
unseen promontory from the canyon floor.
Karl J. Belser in Blue Interval, Ernest G. Moll,
Metropolitan Press, Portland, 1935.
In its second mile, the Red Blanket trail veers away from the park
and hugs a side of the creek as the canyon narrows. Red Blanket Falls is
one of the most spectacular places in the Sky Lakes Wilderness, an area
adjacent to the park and is under national forest administration. At an
elevation of about 5,000 feet, the falls are the head of Red Blanket
Canyon. The transition to a subalpine forest where prolonged snow
conditions are the rule is apparent once out of the canyon. As hikers
continue along the trail toward Stuart Falls and the park boundary,
trees are more often twisted into the pronounced L-shape so common along
the Cascade Divide.
There are fewer resident plant and animal species at the higher
elevations, largely because of the approximately one degree celsius
decrease in average annual temperature for every thousand feet gained in
elevation. Yet a hiker will more often obtain sweeping views of the
surrounding area. Bald Top is one of the points in the park from where
the entirety of Red Blanket Canyon can be seen. Little known even among
park rangers, Bald Top is a product of the once active Union Peak
volcano. That volcano preceded Mazama and its glaciers carved Red
Blanket Canyon, as evidenced by the distinctive U-shape. The other
canyons in the park are more recent and bear the mark of Mount Mazama's
climactic eruption to a far more obvious degree. Nevertheless, they also
play a important role in perpetuating the biodiversity of the greater
Mount Mazama ecosystem.
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