Nature Notes From Crater Lake
Volume 25, 1994
An Overlooked Legacy at Oregon
Caves
By Steve Mark
Virtually all of the structures at
Oregon Caves National Monument are sheathed in bark of the Port Orford-cedar,
Chamaecyparis lawsoniana.
This detail is part of a site design aimed at blending buildings with
their surroundings. Port Orford-cedar (the name is hyphenated because it
is not a member of the genus Cedrus, or true cedar) occurs from the
eastern Siskiyou Mountains to the coast. Although its relative abundance
at one time has been greatly reduced by disease, fire, and logging, a
number of stream drainages in the vicinity of Oregon Caves contain
enough cedar to draw tree lovers.

All buildings at Oregon Caves Natonal Monument are
sheathed in cedar bark, including the Chateau, seen here in this 1937
photo by Francis Lange.
Below the cave entrance area, Port
Orford-cedar can be seen on Cave Creek as you leave the monument and
follow the trail toward Cave Creek Campground. The remaining trees are
along the fringe of several clearcuts, but there are enough of them to
make a worthwhile walk. In this part of the Siskiyou National Forest,
Port Orford-cedar is found in riparian areas or places where seepage is
a foot or less below the surface. The tree can be identified by
elegantly sweeping boughs and lacy foliage, as well as by a red brown
fluted bark that can weather to a slight silver tinge with age. In this
setting, Port Orford-cedar is often associated with an attractive
understory of Pacific rhododendron,
Rhododendron macrophyllum, or western azalea, R. occidentale.
Many visitors to Oregon Caves are
unaware that they can see Port Orford-cedar on the trail to Big Tree.
The "cedar" occurs throughout this part of the monument's mixed conifer
forest, though many visitors focus on the large Douglas-fir,
Pseudotsuga menziesii, such as Big Tree or sugar pine, Pinus
lambertiana. A young stand of cedar can be seen amid the Douglas-fir
and Bigleaf maple, Acer macrophyllum,
in Panther Creek downslope of Big Tree with some off-trailhiking. More
impressive stands can be seen by taking the longer segment of the loop
trail to Big Tree. Although sometimes steep, this route also provides
access to Mount Elijah or a return to the cave entrance area.
The most serious threat to Port Orford-cedar's
survival throughout its range is the pathogen Phytophthora lateralis,
a root rot fungus. It has infected several stands just three miles from
Oregon Caves, killing a number of trees. The cedar is particularly
susceptible to Phytophthora's waterborne spores because its roots
intermingle with those of other trees in drainages downslope of where
infection has occurred. U.S. Forest Service researchers hope that Port
Orford-cedar's genetic variability may allow for some resistance to the
disease even in heavily infected areas.
Other than small numbers occurring in
Redwood National Park, no unit of the National Park System perpetuates
Port Orford-cedar apart from Oregon Caves National Monument. The cedar
population in the 480 acre monument is so close to infected areas that
measures are needed to prevent the root rot's spread to the park. One
preventative measure is to keep hikers and vehicles out of places where
the fungus spores can be transported into uninfected areas. This is
especially important in the spring, when wet boots and tires can become
agents for transmitting the fungus.
Phytophthora has considerably less
chance of infecting Port Orford-cedar in summer, but another threat -
wildfire- increases as fuel moisture levels d op. Catastrophic fires can
occur throughout the cedar's range wherever the explosive combination of
low fuel moisture, high winds, fuel loads, and an ignition source
occurs. Although mature Port Orford-cedar can survive low intensity fire
with its thick bark, it was only prompt action by fire crews that
stopped the Caves Fire of 1989 from engulfing the monument.
If the Caves Fire had not been
contained, more then the commercial and aesthetic qualities of a forest
with some Port Orford-cedar component would have been lost. Oregon Caves
National Monument has some of the finest rustic architecture in the
national park system. One structure, the Oregon Caves Chateau, is a
national historic landmark. It and four others comprise a district
listed on the National Register of Historic Places. The bark on these
and other structures has proven to be exceptionally durable, requiring
only occasional replacement after 50 or more years. Port Orford-cedar's
durability and past availability are factors in the survival of some
pioneer cabins in the Illinois Valley. With age, the wood bleaches white
and is why the tree is sometimes called "white cedar." Several examples
of cabins that utilized white cedar are on display at the Kerbyville
Museum.
Interestingly enough, the landscape
architect who proposed that the monument's buildings make use of cedar
bark also was concerned about the rapid cutting of Port Orford-cedar on
the Oregon Coast as early as 1925. He and other proponents of a state
park thought it to be as distinctive as coast redwood, Sequoia
sempervirens, and knew that the Port Orford-cedar shares some
similar attributes with redwood. Efforts to establish a state park
stalled, so the U.S. Forest Service set aside two areas on the Coquille
River in Coos County as research natural areas in 1938.
Feasibility studies for a Port Orford-cedar
national monument by the National Park Service were the impetus for
attempts to expand Oregon Caves National Monument in the 1940s. A fine
sample of Port Orford- cedar existed along the ridgeline from the
national monument to Grayback Campground, but logging during the 1960s
and 1970s dealt a severe blow to hopes for a larger park. Nevertheless,
part of Grayback Creek is still lined with Port Orford-cedar, as any
adventurous motorist will discover if they take the road toward Low
Divide and Williams.

Port Orford-cedar branch and cone Cedar
branch: George Seedworth, Forest trees of the Pacific Slope,
Washington, DC: U.S. Government Printing Office, 1909, p. 173;
Cone: Hickman, p. 113. |
Stands that Elijah Davidson would have
seen on his way from Williams to discover Oregon Caves in 1874 persist,
but in dwindling numbers. The cumulative impacts of disease, fire, and
logging are compounded by the practice of replacing Port Orford-cedar in
managed forest with other conifers. Consequently, the perpetuation of
the tree in its native habitat will be difficult because its standing
volume has been reduced to 15 percent of what it was estimated to be in
1850.
Although timber cruisers are quick to
recognize Port Orford-cedar's value because it has commanded the highest
stumpage price of any commercial softwood for the past 40 years, it
remains relatively unknown by the public. Unlike the coast redwood, Port
Orford-cedar does not dwarf its surrounding conifers and rarely occurs
in pure stands. In addition, Port Orford-cedar and Incense-cedar,
Calocedrus decurrens
are often confused with each other. Indeed, the Port Orford-cedar is
so highly imitative in adapting to a wide range of environments that
many tree lovers do not suspect that it occurs among the coast redwood
of Jedediah Smith Redwoods State Park. As a result, Port Orford-cedar's
significance has been largely overlooked. It can only be hoped, however,
that the tree does not become a lost legacy.