Volume VI No. 4 - September, 1933
Wizard Island: It's Succession Of Life
By Dr. Wm. G. Vinal, Ranger-Naturalist
Wizard Island is never the same twice. As the same moment no two
people see it the same and it is only by continuous observation and
accretion of ideas that the complete story of its origin and life can be
unfolded.
It is evident to an observer on the Watchman, Hillman Peak or Llao
Rock, looking down on the island, that it is made up of the three zones
of volcanic contributions, namely blocks of rough andesitic lava at the
base along the shore line, a coarse undulating lava flow along the
intermediate slopes and the symmetrical conical slopes of ash and
cinders above. Disintegration and decomposition have not contributed
much to the breaking down of these lava slopes. The volcano is so young
geologically that very little progress has been made in converting the
raw slaggy slopes into a soil with humus. A slight covering of volcanic
dust co-mingled with organic material has filled the more gentle slopes
and irregular crevices as the base. It is evident that there is not
sufficient soil nor is the humidity sufficient to invite the growth of
such shade plants as the coral root, trailing raspberry and a host of
other deep wood plants.
Darwin's classical earthworms have not arrived nor could they find
any subsoil to bring up to the surface. The plants on Wizard Island,
therefore, are limited to those forms whose structure allows them to
suffer drought.
The stages in the vegetal conquest of Wizard Island may be the key
to the many successive revegetations of the slopes of Mt. Mazama. What
were the first plants to land and how did they come? After the last
swirling flow of lava and the vanishing of steam there were, as always
before, prevailing westerlies wafting spores of lichens, fungi, and eric
mosses and perhaps the winged seeds of conifers from the Rim. The water
currents undoubtedly floated seeds. Probably 99% of these germs of life
were born for naught as is the great mass of pollen that washes to and
fro today. Many would-be colonizers were destined to land on such
barren, sterile places that they were inevitably doomed to perish.
The only plants today that are succeeding in the glare of light on
the lower rock blocks are the lichens. The golden lichen is a crustose
form which can stand a certain amount of direct sun but must have shade
a part of the day. The gray lichens could also have been early
arrivals. It must have been eons before any crannied wall accumulated
dust particles enough to encourage a moss plant. The lace fern
(Chelianthes gracilliam) grows in pockets on the lower rock
ledges, Woodsie (Woodsia oregana) pokes its rusty fronds from
protected spots on the rocky summit, and the rock brake (Cryptogramma
acrtostichoides) is found in rock clefts in the crater. Those are
the only members of the fern tribe that have succeeded in mastering the
situation. Untold ages had to follow before seed plants could anchor
long enough to send their rootlets down to the water table.
In the meantime what could have been going on in the way of seed
arrivals on the ash pile above the cone? It is a mile from the west rim
across Skell Channel to the crater of Wizard Island. It must have been
a strong west wind that enabled the first mono-planed seeds of the
conifers and the ballooms of the composites and figworts to flutter from
the rim of Crater Lake to the sides of the island cone. There had to be
at least one from each conifer, the mountain hemlock (Tsuga
mertensiana), the white bark pine (Pinus albicaulis), the
western white pine (Pinus monticola), the lodgepole pine
(Pinus contorta), and the shasta red fir (Abies magnifica
shastensis). It may not be sheer accident that the greatest growth
of evergreens is on the west side of the island, that the largest and
possibly oldest western white pines and Shasta red firs are at least
five hundred feet above the lake, or that the best stand (of) lodgepole
and white bark pine is at the summit. In other words, did not the
colonizers come by the air route and land as they would, hit or miss,
but mostly miss? The seeds successful in growing. The ash cone proved
to be the best of the three areas. It was these veterans that lived to
perpetuate each its own kind. They remained to shake their seeds
downward that the forest might grow upward to eventually cover the cone.
The five conifers had a most difficult time in establishing
themselves. The remarkably few evergreen seedlings on the ash slope are
mute testimony to the fate of most seeds which are unfortunate enough to
cast their lot on such a dry, sterile environment. Those which
succeeded in reaching a goodly size still had to fight. About 500 feet
up the cone lava rocks from a fissure flow have imbedded themselves
eighteen inches above the slope in the trunk of a Shasta red fir and at
a still higher altitude a lava rock as large as a man's head has become
wedged between the upright trunks of a white bark pine. Such land
slides are denuding agents for seedlings and surely handicaps to veteran
tree. In one of the larger gullies the larger trees have had their
heads snapped off about twenty feet above ground. The fact that they
held fast with their root systems indicates a deep root system, or that
they were broken by a wind storm which whirled up the valley when the
trees were braced by deep snow. Many a wind-blown tree has lost its
main trunk to start again. The battle is with the elements and not with
each other.
And what of the antecedent herbs? The shade-requiring plants of the
deep forest are few indeed. The small-leaved penstemon, the pine-mat
manzanita and the wintergreens represented by the one-sided pyrola, the
toothed wintergreen and pipsissewa are practically the only arrivals.
The representatives of the open woods are the white hawkweed and the
elephant's head. The few herb and shrubs of the forest indicate that
the stand must be young in its development.
The colonizers of the ash slope are the strong-stemmed, creeping
perennials that are able to battle alone. The amount of heat on the
slope is much greater than on the wooded plateau below. Any plant
growing there must be drought resistant, capable of anchoring tightly,
and able to stand punishment when bombarded by pumicite or when buried
alive by miniature sand dunes. Theirs is a terrific punishment. The
typical plants of this area are arenaria, chalice cup, white buckwheat,
and Newberry's knotweed. All of these hardy pioneers send runners into
the bare ash and are often exposed by the drift of the soil. Their
offshoots, rhizomes, or stolons are controlled by gravity and swing like
cables down the slope. This may be thought of as a linear migration (as
opposed to radial migration) and new plants spring up just below the
parent plant. As many as eight successive offspring were counted on one
cable which had been sent out by white buckwheat (Eriogonum
ovalifolium).
Interspersed with the "cable" growths are such hoary and stemless
plants as the silver leafed senecio, and sulphur flower, and the
root-storing carrot (Cogswellia martindalei). In protected spots
the fireweed, Englemann's aster, the alpine, false dandelion, arnica,
and wood rush have made appearance and stand ready to furnish the
strands of crosswise vegetation as soon as the "cable" plants get
stabilized. The vegetation on the ash lope has hardly reached the stage
of being able to weave a mat or turf.
A third zone of herbaceous plants appears near the top of the
island. Although the island does not reach into alpine heights it has a
few plants which are typically montane in character. At the crater a
few yellow mountain daisies (Hulsea nana) grow just outside the
rim on the south side in loose red cinders. A few feet across the
crest, but within the crater and on the north facing slope, is the
heart-leafed arnica (Arnica cordifolia) and the more widely
spread alpine saxifrage (Saxifraga tolmei). This little
saxifrage starts as a tuft in back of a rock and in due time forms a
dense mat. The silver-leafed senecio (Raillardella argentea)
grows on the dry ash of the north slope outside the cone and penstemons
adorn the inner slope. While in the "cable" plant district it is
largely ability to adapt to a small amount of moisture and shifting
soils around the crater it is a matter of little moisture and direct or
indirect sunlight.
The trees are herbaceous plants listed are those whose seeds could
have been brought by the wind. The shrub plants with berried fruits
also came by the air route except that they borrowed their wings. Only
two shrubs of red berried elder (Sambucus racemosa) were noted on
the cone. One was at an altitude of 6650 feet and the other at the
bottom of the crater. Four little offspring are growing near the base
of the crater specimen. A solitary gooseberry bush was found at an
altitude of 6250 feet in the forest. The scattered appearance of the
many-stemmed mountain ash (Sorbus sitchensis) with its berry-like
apple, the pine-mat manzanita, and the mazama currant have all appeared
above the encroaching forest. The pine mistletoe (Arcenthobium)
could well have taken the bird express to the white bark and lodgepole
pines on the rim of the crater.
The pine mistletoe could not arrive before its host. The same is
true of parasitic paint brushes. The aphids in the rolled red-leaves of
manzanita had to wait for the hosts' arrival. The tiny craters of the
"doodlebugs" (Ant Lions) found at such widely separated stations as the
first trees above shoreline (6207 feet), the upper limit of the shady
forest (6437 feet), the fissure flow at 6610 feet in altitude and the
top of the rim (6940 feet) show that such barriers as Skell Channel,
bare lava rocks, or ash deserts are not insurmountable. These
carnivorous insects must have followed the advent of required food as
was the case of the dozens of dragon flies hovering over the crater
(August 10, 1993). And how about the toads sitting patiently in the
crater waiting for food to pass by? Were they and the dragonflies and
the mosquitoes crater-born or channel-born? Wizard Island may thus be
compared to the House-That-Jack-Built, for this is the ant lion that ate
the ant that lived in the tree that came from the seed that grew in the
pumice that was blown out of the crater that Wizard Island built. Or,
this is the egg, laid by the beetle that came from the grub, that
infested the bar, that belonged to the lodgepole, that had the "rumor",
caused by the spores that came from the parasite that lived on the
paintbrush (for four generations) that grew on the slope, beside the
trail that Jack built. And so one may go on ad liberatum.
An abundant insect life readily invites bird inhabitants. The
mountain blue bird family on the rim would indicate that a pair had
nested thereabouts. The redbreasted nuthatches and Oregon Juncos
appeared busy and happy. The Calliope humming-bird was observed sipping
nectar from phacelia and fireweed, the Clark nutcracker probing the
cones of the white bark pine on the rim, the marks of the sapsucker on a
white bark pine, and the Cassin purple finch and Audubon warbler feeding
along the evergreened base, the toads near the snow bank, the coney
making hay in the rock slide at the bottom of the crater, the three
golden-mantled ground squirrels near the domicile of the coney were all
dependent "on things" that must have come before.
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