Nature Notes From Crater Lake
Volume 23, 1992
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.