Chapter II: Part 2

The Continental Divide is a mighty barrier, a line of consequence that does more than determine watersheds. Its effect in Glacier is dramatic, as a look at the forests will reveal.

Obstructing the eastward flow of the moisture-laden Pacific winds, the Divide extracts a heavy annual tribute of precipitation from the air mass, forcing it to rise up the mountain chain, where it cools and condenses. Chief benefactors are the low western valleys, which respond with a lush growth of Pacific coastal-type forests.

The eastern valleys, however, deprived of abundant annual moisture and exposed to the wind and temperature ravages of the prairie’s continental climate, support a dramatically different kind of forest. Here Engelmann spruce and subalpine fir are the climax trees, contrasted with such trees as the western redcedar and western hemlock of the mild and moist McDonald valley.

Elevation exerts an additional restriction on the distribution of tree species. Since climatic conditions vary with change in elevation—lower temperatures resulting in shorter growing seasons, and increased wind exposure resulting in greater loss of moisture through evaporation—we would expect to find the forest composition change as we ascend a mountain slope. In Glacier, eastern valleys average 240 meters higher than western, and thus even if they had more moisture they would not sustain the redcedars and hemlocks. All plants have range limits, some narrow, some broad; and they excel where their particular set of preferences as to moisture, soil, sunlight, and wind exposure are best met. On sites that do not meet their optimum requirements, they face being crowded out by species better adapted to the prevailing conditions.

Physical features of the land determine vegetation also. Certain trees prefer the moist areas along a streambed—the great black cottonwoods, for example. And on steep hillsides, avalanches prevent the growth of climax trees, permitting instead only shrubby, pliant growth—mountain-ash, mountain maple, alder, menziesia.

Forest communities are named for their dominant tree species. Thus, an area in which Douglas-fir dominates is called a “Douglas-fir forest.” Glacier does have forests in which Douglas-fir is the climax species; these are chiefly dry areas, below 1,800 meters, with south and west exposures. But we usually associate the park with its Engelmann spruce-subalpine fir forests, found extensively between 1,200 and 2,100 meters, and with the western redcedar-western hemlock forests in the McDonald valley.

Because forests mature slowly and change is usually imperceptible, we are tempted to think of them as static and eternal. But since a forest is a community of living things, it responds to changes in the environment. Subtle physical or climatic changes, such as a rising or falling water table or a slight increase or decrease in annual precipitation, will favor some species of trees and hinder others, eventually altering the composition of the forest.

Other changes are more dramatic. Most notable of these is fire.

From Fire to Forest

Heat lightning, glimmering soundless behind the western peaks. Then the first low rumble. At first the flashing had been from cloud to cloud, but now, as the storm nears, the first ground-spears appear, lighting up the night. Here is a big storm, many-celled, engulfing more and more territory beneath its angry bulk. Lightning dances into the dry August forest. In their towers the lookouts stay awake.

Close strike and a flare-up! The ridge snag burns like a Roman candle, sending bright embers down. Valley, ridge, and peak blink on and off with blue light as the storm roars like night-firing artillery.

Passing overhead, the low cloud belly brings a sudden lash of rain. But it is not enough: tomorrow will mean long hours of fire watch.

The next day dawns clear, a morning of heavy dew. The ridge strikes did not ignite the forest. Inspecting the storm path, aircraft and lookouts find no evidence of fire.

But two days later, in a morning of high wind, thin smoke plumes rise upward. Smoldering in the thick duff of the forest floor, a lingering hot spot explodes with the fanning wind. It quickly spreads from a hectare to ten while the quadrants are called in and the hot-shot crews dispatched; then to a hundred, bringing in the smoke jumpers and mobilizing the vast fire-control network. A thousand hectares, perhaps ten thousand might burn this week of big fires.

In the resulting skeleton forest, the scene of devastation is almost overpowering: life seems forevermore excluded from this blackened ruin. But fire is nothing new to forest communities. We may think fire demonic because it takes from our life span this block of mature forest, a sight we will never again see in this place. But nature does not operate in terms of human time scales. This forest is simply pushed back closer to its starting point, to begin again its long progression toward a climax vegetation cover.

Forest Succession

Through a series of complex vegetation stages, each characterized by different herbs, trees, and shrubs, the forest slowly returns to the type of vegetation best suited to the physical and climatic conditions of the site; this is called a climax community. The fact that most of Glacier’s forests are in some stage of recovery from fire accounts in part for the mosaic of forest cover found here.

The forest of Huckleberry Mountain on the Camas Creek road was consumed in the 1967 fire. By 1969, among the charred, lifeless trunks of the former forest, lush grass and sunloving fireweed, thistle, and paintbrush were growing. And by 1974 lodgepole pine seedlings along the road were a meter or two high. Lodgepole is a fast-growing tree that requires full sun to germinate. Forest fire is necessary for the regeneration of these trees: the intense heat causes the tightly closed cones to open, releasing the seeds that will establish the forest. So young pines developed among fireweed, spiraea, willow, and mountain maple shrubs.

The lodgepole forest near the western entrance to the park has been developing since 1929, when fire destroyed the redcedar-hemlock forest in the area between Apgar and West Glacier. Beneath the scattered spires of old larch that survived the burn, the lodgepoles have now grown up, forming a canopy that shades the forest floor. Because lodgepole live only about 80 years and will not germinate in shade, this forest will not exist long. Shade-tolerant Douglas-fir, white pine, Engelmann spruce and western redcedar seedlings are now taking hold. But the physical characteristics of this area—the climate, terrain, and soil—are ultimately most favorable for western redcedar and hemlock; and unless other disruptions intervene, this area will eventually again become a dense redcedar-hemlock forest.

But this will not happen quickly. The soil after hundreds of years of collecting debris will again become rich and moist. Young hemlocks will germinate on and near decaying logs. When old larches, firs, and pines fall, the slow-growing redcedars and hemlocks will take their places in the canopy.

Forest succession is a more complicated story than this; it is a fascinating study involving herbs, shrubs, small and large trees, and animal populations. From location to location it will vary; only in its broad outlines is it predictable. It is based on the observation that, given time, a forest—or any other plant community—will progress until it reaches climax—that is, the stage that will perpetuate itself.

■ How then are we to think about fire? Increasingly, experts are concerned not so much with fire suppression as with fire management. For suppression has at least three disadvantages: it allows the accumulation of unburned fuels that can result in “fire storms” when they are finally ignited; an undiversified climax forest is more vulnerable to disease than is a mixed forest; and a dense forest canopy discourages shrub growth, an important food source for deer, wapiti, moose, and smaller animals.

As the well-being of the deer herd depends on the predators that thin its numbers, so the long-term well-being of the forest depends on fire to rejuvenate it periodically. We must realize that wilderness is identified with fire, landslide, avalanche, windfall, and flood. Nature not only has learned to cope with these agents of change—she depends upon them for maintaining the delicate balances between landscape and life. There is in the business of nature, after all, more than the pleasing of man’s eye.

Spruce Morning

Of all times to get a rock in my boot! I had just started out, the morning was still cool in this eastern valley, and the heavy pack was not yet biting into my shoulders. Sitting down beside the trail, I leaned the pack against the base of an old spruce and began unlacing.

I could hear the scratching of the red squirrel descending to investigate, but I didn’t look up until it let go with long indignant chatter at finding its territory invaded. I plunked out the pebble and began relacing my boot. Cautiously the squirrel came down, pausing frequently to scold, its lower jaw quivering with rage and exposing yellow rodent teeth. Neighboring squirrels joined in and soon the trees danced with flicking tails.

Down the squirrel came, almost to the ground, then raced back up the tree, stopping at each lateral branch to deliver a vocal broadside. Finding no danger to themselves, the other squirrels soon quit the uproar and went about their morning business. I was beginning to suspect that I was committing some graver offense than the mere exercise of squatters’ rights—perhaps I threatened its cache of fir cones. Then into the corner of my vision shot another form, streaking soundless as a shadow; the squirrel also saw it—but too late. With a thin terrified squeak, the rodent started to go higher; but the pine marten was above it. The squirrel quickly reversed itself, sending bits of bark showering down.

As the squirrel leaped from the tree in desperation, the marten overtook it in mid-air; they came down together. Clamping the limp creature firmly in its jaws, the marten strode up the incline of a fallen spruce. Before it hopped off onto a shelf of higher ground to disappear, it looked briefly back at me. I fancied I could read, fixed in its eyes, a certain recognition of my having distracted its prey.

A breeze made me shiver, snapping me back from that swift vision of luxuriant fur, that blinding grace which flashed its orange throat-patch through the trees, and I realized I was sweating. For a moment I had been that squirrel, eyes wide with terror, seeing fate bear down, and powerless before the natural order of things.

The incident got the other squirrels singing again; but the confidence was gone, and soon it was quiet. What dreams do squirrels dream, I wondered, looking around. I saw that place more clearly then, having been caught between a marten and its prey. I saw each spruce: its age, its condition, the onslaughts it had borne; the beargrass coming up in an opening; and down the trail a meadow that was yellow, white, and red with sulphur plant, mariposa, and Indian paintbrush. Bees, flies, spiders, and butterflies worked that little garden tucked among the crowding trees. Countless forms of life beneath the soil and bark, in tunnel, crevice, hole, and pocket, working unseen to sustain their lives, and somehow, when all were added up, maintaining the forest as well.

A flicker called, its loud _Klee-yer_ breaking the forest hush. Birds, mammals, plants, insects—all hide together here, their lives so skillfully embroidered that no loose thread exists that my mind might grasp to unravel and understand the work.

The forest had once been a place that obstructed my view, a great blank to stride through, a few hours of necessary blur before the high lake or pass was reached. Now I was quite content to remain awhile beneath these great-boled trees.

■ A forest, like the mountains themselves, supports various levels of life. The floor and substratum are a great processing plant where bacteria, fungi, and insects work, decomposing the plant and animal litter, recycling dead and discarded tissue back to simpler organic compounds, gases, and minerals, thereby providing sustenance for growing plants. As spiders, shrews, wrens, and thrushes seem to know, there is good hunting on the forest floor.

Just above the forest floor is the herb layer, a seasonal layer of growth including flowers, mushrooms, grasses, and other small plants.

Above that grows the shrub layer, then the understory of young trees awaiting their chance to take a place in the forest’s canopy high above. From the swaying canopy, exposed to the full force of sun and wind, to the dim, moist floor, the forest provides a wide range of habitat.

Relatively few animals live in the treetops. The almost incessant motion makes nesting too hazardous for birds. Red squirrels venture up to cut cones in the canopy, but store their booty and make their nests farther down.

In the mid-range between canopy and understory, goshawks and Cooper’s hawks nest. Woodpeckers, nuthatches, and sapsuckers forage on the tree trunks and nest in cavities they excavate or appropriate. Red squirrels and the nocturnal flying squirrels create a major traffic here, along with the martens and owls that hunt them.

The understory and shrub layers house the greatest numbers of nesting birds. Here the effects of storm and rain are minimized and protective cover is greatest. Vireos, thrushes, warblers, hummingbirds, bluebirds, flycatchers, and others can be found among the tangle of this sometimes impenetrable layer.

The most populated area, the forest floor, supports an astonishing abundance of organisms. Below the busy traffic of mice, shrews, and larger animals is a bewildering array of insects and other invertebrates. The attrition rate in the litter of the forest floor—a continual battleground difficult to comprehend—is enormous. The smaller the organism, the greater its numbers are likely to be. This humus-rich, moist soil teems with bacteria, and a handful will contain surprising numbers of small spiders, pseudo-scorpions and almost microscopic mites.

Each year some two to three thousand kilograms, dry weight, of falling material litter an average hectare of forest. All this plant and animal waste—twigs, leaves, limbs, fallen trees, feathers, hair, feces, and carcasses—is processed by the armies of decomposers that thrive on the forest floor. With the aid of larger creatures that break up the plant and animal tissue, most microscopic bacteria are able to decompose from a hundred to a thousand times their own weight every day.

Few trees die of old age in the forest. The seedling mortality rate is necessarily high, since far greater numbers of seeds germinate each year than can reach maturity. Of those that do, many fall victim to the ever-present dangers of disease, insect infestation, windfall, stream erosion, and fire. Insects alone present a formidable threat to trees, for they have evolved every means of attack—chewing and mining leaves, boring into twigs, eating cambium and heartwood, sucking sap, triggering galls. If the insect world did not police itself, aided by spiders, insectivorous birds and other animals, forests and other plantlife would quickly fade before the chewing, boring, sucking horde.

■ Through the trees the light on Citadel shows the morning slipping by. As I start to get up I see a garter snake sliding out into the dusty trail, seeking the sun-warmed earth. Moving slowly, alert for danger, it probes the air frequently with its sensitive tongue. But against the lightcolored duff its dark shape offers a fine target, begging attack. A chipmunk, watching from a nearby lookout stump, twitches its tail nervously over its back, curious—perhaps suspicious—at the sight of a snake. Very slightly the snake’s head goes up, its tongue flickering. For a few seconds reptile and rodent regard each other. Then the chipmunk drops back soundlessly into its hollow stump, and the snake lowers its head onto warm ground.

Some day soon, a sparrowhawk or weasel will interrupt the snake’s morning sun-bath. The snake will fuel bird or mammal for a time, as mice, fledgling birds, and insects now sustain the snake. The chipmunk too, rummaging nearby, lives in shadows of talon and tooth.

Until that time of sharp encounter, each has its own niche, a way of life, a shaft of sun, and food enough.

A Walk in the Redcedar Forest

Climax! The word takes on a true significance here, among these broad-based trees. When you enter this forest the road noise does not follow far—as, when you walk into a cave and turn a corner, sound and light are left behind. There is a surprising spaciousness, a feeling of openness in a mature western redcedar forest. With scant understory and the canopy so far above and everywhere complete, it seems like some vast, high-ceilinged catacomb, pillared by the huge, shaggy-barked cedars and the deeply scored trunks of the black cottonwoods. The floor is strewn with fallen giants in magnificent disarray, uplifted roots still grasping fractured rock.

A rainy day is a good time to walk a cedar trail, when the dull light seems to shine from the wet moss, making the underleaves of devil’s-club and Rocky Mountain maple glow. Wind and rain, like light, penetrate with difficulty the latticework of this canopy; thin lines of fog develop over the bogs. The air is fresh with growing plants, snow-cold still when the first spring flowers appear.

Fiddleheads of unfolding lady ferns line the trail in May, pushing up from the hub of last year’s leveled, lifeless fronds. Beds of trillium shine their white, three-pointed flowers like flashlights in the dark recesses. Unlike the small, hidden calypso orchid, which bears its purple spikes and yellow throat low above the moss, the trilliums make no secret of spring growth. They are bold, handsome plants, broad-leaved and tall, with waxy white petals that tinge to purple in their month-long bloom.

Moss covers everything. Boulders are green and weightless-looking, resilient and topped with miniature forests of cedar seedlings. Ancient fallen trees are disguised with blankets of moss, sprouting hemlock here and there. The rich greens that characterize Glacier’s summers seem to begin here amid the moisture-glossed leaves of twinflower, bunchberry and bead-lily.

Later, the spiders will spin thousands of kilometers of gossamer filament among the trees. The orb-weavers will hang their webs high and low, suspended in every opening. Walking through the forest then, you will see shafts of sunlight whirling in the higher webs until they seem like tops set spinning among the treetrunks.

Indianpipes, the “ghost flowers” that need no light to grow, will break through the forest soil. Like mushrooms, with fruiting bodies that are nourished by underground mycelia, these saprophytes absorb their nutrients from a fungus that covers their roots.

Receiving an average of about 18 centimeters more annual precipitation than forests east of the Divide, Glacier’s redcedar-hemlock community hoards its moisture. Its dense growth and the surrounding mountain walls inhibit the circulation of drying winds. Mosses and ferns transpire their moisture, which you can feel; place your hand close, and you will sense a coolness like the air exuding from an ice cave. Draped from the tree limbs are long filaments of squawhair and goatsbeard, black and grey lichen strands that flourish in the damp air.

Except for the black bear, few large animals inhabit the deep forest. Grizzlies find better forage in meadows or along the forest edge. Since shade discourages shrubby undergrowth, deer and wapiti will search elsewhere for browse. In summer, wapiti, grizzlies, and mule deer bucks tend to wander up into high meadows.

Contrasted to the noisy, conspicuous birds of the prairie—meadowlarks and bobolinks—birds of the forest seem elusive and secretive. Although numerous, the varied thrushes, Townsend’s solitaires, and Swainson’s thrushes are seldom seen; but when approached, they fly silently off and are swallowed by the forest shadow.

There seems to be serenity in a mature forest, as though the struggle for life is somehow suspended, the needs of the animals here less urgent, muffled. The towering redcedar forest seems to be no battlefield at all, but rather a monument to what Earth can do.

The Perpendicular Night

Behind Avalanche campground a trail leads back toward Lake McDonald Lodge. I decided to follow it one June evening, to experience the sensation of the deep forest changing into night. With the nearby mountain wall intercepting the sun, dusk comes early to this valley. On the prairie, night passes across the landscape in an even line, forthright as a waxing tide; you can almost feel the globe in its turning from the sun. There is reassurance in the night’s coming, its steady purple doming over the sky.

But here darkness seems to sprout from the earth. It collects beneath the hemlock clumps, bridges the creekbottoms. It seems to flit from place to place. You look about, uneasy, trying to catch it here or there, but always miss its infiltrations. It captures the narrow clearings when you look away; pockets of tree-darkness join together, forcing the light upward until the tree-tops seem impossibly bright and distant.

Through the trees I could see a dozen fires dance in the growing shadow, wood-smoke and camp sounds filling the air. Turning uptrail, I felt a reluctance to leave the presence of those fires—a senseless feeling, but strong. A growing forest-dread impelled me almost physically backward to those circles of firelight. I felt the need to be near a fire, to be reassured by heat and light. Fire was our greatest friend, our greatest weapon. With it we beat the long ages of ice and held the forest gloom away. There was no harm here, only silence; yet the longer I walked, with beard-moss hanging down like daggers all around, the more I craved the comradeship of fire.

_Continued on p. 104_

The Vital Predator

The merciless law of predation might at first thought seem cruel;
but the predator plays a vital part in maintaining the balance of
the biotic community. Without the controlling factor of predation,
prey species quickly enlarge their populations. If plant eaters are
not checked, the resulting excess population exceeds the carrying
capacity of the range. Food supply rapidly diminishes. In a damaged
range, competition and stress result, usually culminating in a
massive die-off through starvation and disease.

Ironically, predators thus provide a service to their prey. First to
fall to the predator are the old, the diseased, the unwary, and the
young. By removing many young and old deer from a typical herd,
cougars lessen competition among the deer for choice range, thus
tending to keep herbivore numbers at parity with the land’s carrying
capacity. Only the strongest and wariest deer survive, ensuring that
the fittest will continue the species. When man upsets this delicate
balance—destroying predators in the hope of increasing numbers of
game animals—the result is ecological disaster. In the 1930s, in a
misguided attempt to “preserve” the whitetail deer herds of the
park’s North Fork area, many coyotes and cougars were exterminated.
In 1935 alone, 50 cougars were killed. Relieved of the pressure of
predation, the deer flourished. In a few years, however, the
normally adequate range was severely overbrowsed. Suffering also
from this imbalance were wapiti (“elk”) and moose, ungulates that
share the winter range with deer.

Some predators are more specialized than others. The Canada lynx,
for example, has oversize feet, an adaptation that helps it move
across deep snow without breaking the surface. As a result, it is an
efficient predator of the snowshoe hare, another large-footed
animal. Relying on this adaptation, the lynx feeds almost
exclusively on snowshoe hares. Consequently, its numbers inevitably
fluctuate with the 10-year “boom and bust” cycle of the snowshoe.

The coyote, on the other hand, is a generalized predator, exploiting
whatever prey is currently abundant. Should mice or ground squirrels
be in short supply, it will subsist on anything from grasshoppers to
berries until favored prey again becomes available. (Animals that
normally eat both plant and animal food are referred to as
omnivores.) Generalized predators are thus better equipped to
survive temporary ecological imbalances, maintaining their numbers
at relatively consistent levels from year to year.

Carnivores all, the animals on these pages illustrate various
adaptations for capturing prey.

Protective Coloration

To escape extermination, each species must in some manner foil its
enemies. Protective coloration is one of the more common adaptations
helping to do this. Most animals resemble their environment to some
extent. The conspicuous markings of some, like the bitter-tasting
monarch butterfly or the striped skunk, seem to function as a
warning to prospective predators that it is in their best interest
to look elsewhere for a meal.

Some animals, such as the white-tailed ptarmigan and the snowshoe
hare, have seasonal changes in plumage or pelage, wearing white in
winter and brown in summer. Even predators, such as longtail and
shorttail weasels, benefit from seasonal camouflage. Protective
coloration makes them less noticeable to prey species and to larger
predators.

Many insects, too, change coloration with the season. Bright green
grasshoppers of early summer become more brown with each molt,
matching the changes in the surrounding vegetation.

_Obliterative shading_ is especially important to animals that
frequent more than one habitat. Seen from above, turtles match their
dark background; from below, because of their lighter underbody
shading they blend into the bright skylight.

_Disruptive coloration_ aids in breaking up an animal’s outline.
Butterflies and moths commonly have disruptive wing markings. The
distinctive shapes of eyes can be concealed. Eye coloration may
mimic body color—as in the green katydid—or the eye may continue
disruptive body markings.

Ground-nesting birds are especially vulnerable to attack. Their eggs
tend to be heavily blotched with earthy colors, making them less
conspicuous. Chicks also carry these disruptive colorations on natal
down.

Most mammals, with coats of brown or gray, are inconspicuous when
motionless. Deer fawns are endowed with speckled coats, mimicking
the sun-flecked forest floor; this disruptive coloration, coupled
with absence of scent and their instinctive “freezing” behavior,
makes it difficult for predators to detect them.

The whitetail deer not only uses its white “flag” to warn others in
the herd of danger; it also allows a pursuing predator to use it as
a target. When the tail is suddenly dropped—abruptly obliterating
the bright white patch—the deer seems to disappear into its dim
surroundings.

Since overly conspicuous animals are prone to predation, natural
selection favors development of appropriate camouflage.

_Ursus arctos horribilus_: The Vulnerable King

At the apex of the food pyramid, this great beast is unquestionably
the king of Glacier’s biotic community. Yet the long-range future of
the grizzly bear is uncertain. With the grizzly exterminated from
most of its former range—which once extended into the midcontinent
and south into Mexico—its numbers have dwindled in proportion to its
diminished range. Present concentrations in the contiguous United
States remain in and around Yellowstone and Glacier National Parks.
Probably fewer than 200 of these magnificent creatures live in
Glacier National Park.

Grizzlies are easily distinguished from the more common black bear.
In addition to larger size and heavier build, grizzlies have a
characteristic shoulder hump; long, conspicuous claws; and a broad,
concave face that gives them a “dished-in” appearance. Fur is
usually brown; like the fur of the black bear, however, color may
range from black to yellowish. Light tipped hairs make the fur
appear frosted, giving rise to the nickname, “silvertip.”

Grizzlies, popularly considered arch predators, are more accurately
described as omnivores. Carrion, grasses, cow parsnip, and several
species of berries, bulbs, and tubers make up a grizzly’s diet,
along with insects, small mammals, and an occasional ungulate that
it can catch. As a result, grizzlies play several roles in the
biotic community, functioning as herbivore, scavenger, and predator.

Ranging widely in all life zones, grizzlies follow the spring
snowmelt up to the alpine meadows, returning to lower elevations to
hibernate from November until April. One to three cubs are born in
midwinter during hibernation. Since the maternal bond lasts two
years, a sow will accept a mate only every other year. Mortality of
subadults is high, resulting principally from competition among the
bears themselves. As with most animals, range—habitat—appears to be
the limiting factor of grizzly populations.

The grizzly is normally shy and fearful of man—but highly
unpredictable. Wounded or sick bears, sows defending cubs, young
adults, and bears that have become conditioned to human scent are
the most dangerous. As humans continue to encroach on grizzly
territory, odds of confrontation also increase. Recent fatalities
and personal injuries inflicted by grizzlies pose a vexing problem
to the National Park Service, which is charged with visitor safety
on the one hand and protection of the park’s remaining grizzly
population on the other. Continuing study of grizzly ecology and
increasingly enlightened bear management programs will, it is hoped,
allow man and bear to co-exist in a wilderness both require.

Bald Eagles and Kokanee Salmon: A Recent Gathering

In 1916 the kokanee salmon, a small, land-locked form of the Pacific
coast species, was planted in the Flathead drainage. With the first
planting augmented by additional stockings, the fish thrived in
cold, deep Flathead Lake, and, to a lesser extent, in Lake McDonald.
The salmon fed almost exclusively on zooplankton.

By the mid-1930s, salmon runs were becoming established. The outlet
of Lake McDonald provides an ideal spawning site for the salmon. The
fast-flowing water is clear, cold, and shallow, and the creek bed is
gravelly.

Averaging 0.3 meters in length and weighing less than a half-kilo,
the 4-year-old adult salmon cease feeding and begin to migrate. Many
thousands swim the 100 kilometers from Flathead Lake to McDonald
Creek. Males appear in the creek first, arriving in late September,
and are soon followed by the females.

Using her tail to dig a redd (a shallow nest depression), the female
deposits about 650 eggs. After fertilization by the male, the eggs
are covered over. The adults die within three weeks after spawning,
their bodies exhausted from the rigorous migration journey and the
weeks-long lack of sustenance.

Egg fatalities are high, due to stream erosion and disturbance by
other spawning salmon. Hatching in late March, the fry work their
way out of the gravel and migrate downstream.

Attracted to the 75,000-150,000 salmon concentrated in a 3-kilometer
stretch of shallow water, bald eagles begin gathering at McDonald
Creek in October. It is not known where the eagles come from or
where they go after the spawning run. Glacier has fewer than 20
summer-resident bald eagles, and these are distributed among the
remote lakes of the North Fork area.

In 1939, 37 bald eagles were counted along the creek. By 1969, 373
were reported, representing approximately 10 percent of that year’s
estimated winter population for the contiguous United States. Since
1960, the count has averaged 240 birds. (In 1977 there were 444.)

Eagles feed by swooping down to pluck salmon from the water or by
wading out to grab a fish stranded on a shallow riffle. An eagle may
consume as many as six fish a day. Immature birds are not as adept
at catching fish and may harry adults or other immatures into
releasing their catch.

A Triumph of Many Colors

Grassland, meadow, tundra, or any other area in Glacier suitable for
plant growth and supplied with abundant sunlight produces an
extravagance of wildflowers. This display of various shapes and
colors is neither an accident nor a mere decoration of nature. Nor
would Earth’s recent explosion of mammal and bird species have been
possible without the evolution of flowering plants.

Two hundred million years ago, early in the Age of Reptiles,
angiosperms (flowering plants) had not yet evolved. Plant
reproduction still relied on spores and cones. Then, during the
Cretaceous Period, the last sediments were being laid down in the
inland sea that covered most of Montana. (It was these sediments
that the ancient Precambrian rocks of Glacier’s mountains later
overrode, forming the Lewis Overthrust.) During this period the
evolutionary miracle occurred: flowering plants—grasses, vines,
shrubs, broadleaf trees, wildflowers—inherited the Earth.

The timing was important. As Earth’s tropical climate gradually
changed to temperate extremes during this period, the domination of
cold-blooded dinosaurs ended and the moisture-demanding coniferous
forests that had covered the earth in green monotony began to
shrink. Angiosperms provided a solution to the ecological void:
grasses and forbs grew where trees no longer could. Most important,
relationships evolved between this new class of plants and the
relatively few species of insects then existing.

Insects began to use the pollen of flowering plants; the
angiosperms, in turn, evolved bright petals and nectar that
exploited visiting insects for the plants’ own reproductive
purposes. This partnership allowed insects to diversify rapidly,
evolving new, specialized forms such as bees, moths, and
butterflies. As a result, predatory forms of insects and arachnids
also rapidly diversified.

The most dramatic change, however, involved warm-blooded birds and
mammals, whose high rates of metabolism required high-energy fuels.
Unlike gymnosperm seeds, which contain no protective covering,
angiosperm seeds are surrounded by a fruit. The development of these
highly nutritious seeds, and the attendant explosion of insect
species, ensured survival of the newly evolved birds.

As birds diversified into seed-eaters, insectivores, and carnivores,
mammals, then uncertain little ratlike creatures darting among the
feet of dinosaurs, began a rapid rise to dominance; grasslands
promoted an explosion of herbivorous and carnivorous species.

The evolution of angiosperms, and the animal revolution it made
possible, came with amazing speed. Most significant, it was a vital
first step upon which the meteoric rise of man depended.

Fire Succession: Key to Continuity

Most of Glacier’s fires are lightning-caused. Strikes may flare up
immediately; or fires may smolder in the forest duff for days until
fanned into flame by wind. _Ground fires_ may race through the
forest understory, causing minor damage; or they may bridge the
understory and reach the canopy, thus becoming rapidly spreading
_crown fires_. Under certain conditions, uncontrollable infernos may
develop, generating terrific winds and heat. These rare
conflagrations are called _fire storms_.

Every type of forest habitat has _climax vegetation_—trees and
shrubs that are best suited to the site and thus maintain themselves
indefinitely if not disrupted.

After a major fire, habitat conditions are usually so altered that
the site must pass through several _seral stages_ before conditions
are such that climax vegetation can return. A _sere_ is a series of
plant communities that follow one another in orderly fashion until
climax conditions are again reached.

Sudden hammering made me jump. Above the forest darkness, a pileated woodpecker leaned out from a high larch snag, braced against the trunk by its specialized, stiff tail feathers. This was the first time I had seen this big white-and-black bird, the “cock-of-the-woods.” There was ample evidence of his work: the deep, oblong excavations in the trunk and the pile of large wood chips at its base, both characteristic of this species. Again he hammered, and I could see the chips falling. After a little edge-work around the hole, he extracted a grub and flew off, yammering against the advancing dark.

Near a stream I stopped to sit down, to listen to the water and maybe catch sight of some small animal. Across the narrow defile, from a slope dense with young hemlock, came the buzzing note of a varied thrush. Several notes followed, all on a different pitch, all drawn out, level and clear; the quality was pure but songless, disjointed, deliberate, like someone testing the reed of a strange woodwind. There seemed no gladness in the heart of this thrush. The song was dark, haunting, lonely.

On the trail ahead I could make out a bird hopping rapidly along. After passing the spot I could hear its song. There couldn’t be a hundred meters between us, yet it seemed to be coming from a great distance. I listened for as long as it would sing. I tried to hear it for what it was, a male Swainson’s thrush proclaiming its territory. But the ethereal, flute-like phrases seemed an evensong made not for man’s ears but only for the forest itself.

I hurried on after the bird had ceased. It was getting dark beneath the trees, but I was beginning to be aware of creatures underfoot, the mad dartings of shrew and vole, more imagined than seen. When a deer mouse jumped away I got out my flashlight. Soon the beam caught a woodrat sitting atop a fallen log. The light didn’t bother him in the least; as I approached, he picked up his bushy tail in his forepaws. Whiskers twitching, he looked more caricature than real. Then he bounded off the log with graceful, arching hops, and disappeared into the night.

Against a patch of sky that appeared in a clearing, I could make out bats, circling and dipping like swallows. Locating a hovering moth, I kept the light beam on it until it vanished into a furry streak of silence. It was time to head back.

By now it had become utterly dark within the trees, a moonless, sightless, alien world, given over to the marble-black eyes of the small night mammals and the creatures that hunt them. I thought of the strange, unseen societies of the flying squirrels, the nocturnal counterparts of red squirrels; of the great-horned owls, inspecting the same ground the goshawks scanned during the day. Perhaps a foraging red fox moved through the darkness nearby, or a coyote on night patrol.

The flashlight beam probed ahead along the trail. The exposed roots were given unnatural shading and they seemed to thicken and squirm as I approached. On either side the tree trunks appeared to step backward from the dim glow of the light. I felt lost in this night, thinking of the great darkness in all the timbered ridges that ran westward from the Divide. In this vast cathedral of crowded tree and peak, night was stood on end, the stars shrunken to a circle overhead, as if seen from the bottom of a well. Mouselike, shivering, insignificant in this wilderness, I scurried back to find a fire and fill my empty senses with its heat and snap and light, holding off the fright of night and thinking of tomorrow’s sun.

Scrub-Forest

The crowning beauty of Glacier—the high, cirqueheld meadows that scent the wind with wildflower and waterfall—belongs to the zone of scrub-forest.

At Logan Pass you are introduced to the highlands. Here an exquisite upland basin holds the Hanging Gardens, a wildflower-clothed gradient laced with stair-step bogs and lines of wind-bent subalpine fir. In the dawn sun, before the first engine noise, it shines unbroken, dewbright and sagging like a spider web secured to the circle of surrounding peaks.

This is the region the hiker remembers best. The tall mountains wear this zone close to the cliffs, and the trails encounter it near the passes or follow it for long, level stretches, as along the Garden Wall. I remember Preston Park and Fifty Mountain, the fire-touched bench of Granite Park and the first sight of Sperry chalet, built on a brow of rock at the upper reach of trees. But most of all I remember the terrible waterfall that becomes Bowman Creek, the plunge of nearly a kilometer that drains the magnificent upland bench called Hole-in-the-Wall.

Hole-in-the-Wall

September. The season is growing late, the meadow-rue dying and the leaves of the wild strawberry failing at last. Everywhere the red contagion of autumn surrounds the vital green. The lower valleys have lost the whistle of ground squirrels. They sun themselves no longer these late, mild days. Ripe, sluggish, and hawk-vulnerable, they sensed the need of hibernation.

It has been eight years since I last visited Hole-in-the-Wall, but I retain its dimensions and hear its dozen waterfalls at will. Once you have seen this basin you have a measure by which to judge the high country and a thirst for the meadows at tree-line.

In Glacier, treelimit ranges between 1,850 and 2,300 meters, depending on local conditions. The upper limit of tree growth—rarely an even, horizontal line—is generally an indistinct band running erratically across a mountain’s face: a tension zone reflecting variations in wind and sun exposure, degree of slope, snowpack accumulations, and the presence of adequate soil and water.

Subalpine fir, whitebark pine, and Engelmann spruce do not relinquish easily their upward climb; where conditions become severe, their growth is retarded and their stature dwarfed. Deformed and pruned by wind, their leaders winter-killed when they outreach the protection of the winter snowpack, trees become shrubs, forced to hug the ground. Size belies age in these elfin forests, or krummholz, where the growing season is painfully brief and progress is always uncertain. A twisted, gnarled little bush, more snag than live branch, bearing a single cone or two, may be senior by a century to the giants of its race in the valley below, which yearly shower the ground with an abundant crop of cones.

This time I will come from Goathaunt, passing Lakes Janet and Francis, reaching Brown Pass from the east, and camp in the spectacular garden between Brown and Boulder Passes.

Meadows and rock slides break the forest as the trail gains elevation and distance through the valley. The spruce and fir thin out rapidly at the valley head, the trail climbing the grassy slope to low, broad Brown Pass. Below the pass is Thunderbird Pond, which receives the meltwater from a glacier high on a shelf of Thunderbird Mountain and is bordered by a low jungle of willow. In the water stands a bull moose, its heavy, fully formed antlers ready for the season’s impending business.

I was hoping again to see Cassin’s finches and Audubon’s warblers on the pass; but the fir grove is quiet. Sitting down to rest and listen, I become aware of a strange silence. No birds sing or flit among the trees, no alarms pass back and forth among alert ground squirrels. There is no wind—an odd condition for the Continental Divide. This place seems to be holding its breath. High overhead, a veil of cirrus cloud arranges long spears across the sky.

Moving off the pass, along the dome of Mt. Chapman, I experience anew the old excitement of this high country. Abruptly the gorge of Bowman valley opens up, revealing the twisting blue snake of Bowman Lake far down the narrow, cliff-imprisoned valley. Here again are the northern titans—Numa, Peabody, Boulder, Thunderbird, and Rainbow; and Carter, with its high glacier baring blue ice teeth to the sun.

It is not the climb that makes your heart pound now; the trail is suddenly narrow and cliff-defiant, cut by the plunging waters of snowbanks far above. These are splendid peaks, unmatched in a land of muscled, brutal earth. Even the air seems to retain the scent of glacier work.

At last the view of Hole-in-the-Wall, a staircase cirque excavated between the gigantic spread ribs of Mt. Custer. The slopes of beargrass are seed-spotted and gaunt now, the white fullness gone. Western pasqueflowers have accomplished their magic transformation; known in this season as old man’s beard, they nod their tufts of grizzled seedhead silk in the wind. Red and yellow monkeyflowers bloom yet, crowding along the many stream courses, and waterloving sedges and mosses surround pools of collected water on the broad horseshoe tiers.

A spur trail drops down into the campground on the last ledge. Through a cleft in its lip plummets the gathered water of the basin. From the valley below, the waterfall appears to be springing from a hole in the headwall, giving this basin its name. Down, down, down, roars the water where once a mighty glacier ground its teeth.

I leave until later the making of camp; by now the sharp shadows of Boulder Peak stab the valley forest and are beginning the upward assault of Thunderbird.

Around the basin headwalls, last winter’s snowbanks remain formidable. Snow caves send out meltwater torrents. Glacier lilies and patches of spring beauty line their fringes. Pasqueflowers bloom in pockets. Here, among the asters of August, bloom also the first flowers of spring, shooting up as the snowbanks shrink, making these spots of snow-free ground a patchwork of May and July, August and June. The shrubs that line the furious water are willows, still bud-swollen this tenth day of September. The coming days will bring a sharp surprise.

Winter will soon stop the melting of this snow. Could it be that I am seeing the first year of a reawakening ice age? If so, each year the snowfields would grow thicker and broader, connecting the shelves into one ice mass again, lilies and willows entombed, the summer heat failing to rescue them, until the ice at last began to slide, stripping the soil and once more plucking at living rock.

Then these dwarfed fir, which cling precariously to the cliffs and hide behind the backs of boulders, would be in more danger than they were from their recent antagonists. Engulfed by ice, they would know the shearing wind no more. Their skeletons would rain down into the valley below, signalling another long forest retreat. But they have waited out the mountain ice before and would send their seeds again to this valley, changed however it might be, as they have always done.

Evening brings out two sleek mule deer does. As they graze, their large ears stand erect, sorting out the lesser sounds from the ceaseless roar of water. Both raise their heads and point their ears, statue straight, at the scuttle of a porcupine. A noise among the rocks draws a backward glance and focus of those ears. I would like the sensitivity of such fine equipment, to hear what deer have always heard.

Setting about the business of camp, I wonder about those animals that watched me for a while, then moved off, having seen a tent go up before. With the appearance of the moon the wind increases and they test the air more often now. Do they have visions of cougar or grizzly with every snap the wind delivers?

In summer these high meadows see a surprising variety of animal life. Briefly out of hibernation are marmots and the handsome golden-mantled ground squirrels. Mice, voles, shrews, and woodrats run among the shadows, feeding on the season’s feast of seeds and insects. A nightmare for these are the fierce little weasels that haunt the rocks.

Tracks of cougar and wolverine are sometimes seen, often teasingly fresh; to glimpse either of these elusive predators is to taste the finest wine of wilderness.

Before the berry season, grizzlies grub the meadows for the tasty bulbs of glacier lilies and the tubers of spring beauty; often distracted by the scent of a ground squirrel in its burrow, they sometimes make a huge excavation for a small reward.

White-crowned sparrows sing in July from the low tops of the battered trees, though their nests are on the ground below. Grey-crowned rosy finches patrol the drier ground for seeds while water pipits hunt insects in the wet areas. High above, a golden eagle scans the basin again, circling slowly before following a ridge south to sight another likely slope in its 10,000-hectare territory.

The moon shines through the tent top. The wind, blowing more violently now, shivers the nylon and interrupts the voice of the waterfall. I have followed the pasqueflower run from the April prairies here to its highest bloom near treeline. I think about the triangular seed pods of the glacier lilies, colonies of steep-throated blue gentians, and the season’s last glory of goldenrod. Indian paintbrush, from white to fire red, blazes the slopes that light the fringes of sleep.

I awake to a determined rain, the moon gone and the tent shuddering with wind-blast. I try not to think of the steel-cold air, and slip into a fitful sleep that seems an endless treadmill of rocky trail.

Stiff and unrefreshed, I look out into the dawnless morning. The tip of Thunderbird is detached from its base by grey clouds swirling at its throat. A wave of sleet slants down, dancing on the rocks, chanting triumph over the buried, bent, and broken flowers of yesterday.

So I must make my escape, short of Boulder Pass. Unattainable now, invisible above the cirque, that high pass grows in my memory. This testament to what a glacier can do, to the struggle of trees and the life-pioneers that invade such harsh places, is at my feet but shrouded with snow. My hands grow stiff and numb in the blunt work of packing up.

I had wished to see Kinnerly Peak again, rising from the western Kintla valley, and walk along black ledges of the lava that floors the pass. Beyond it grows a grove of subalpine larch, stately, seldom encountered, the least common tree species in Glacier. Confined to this narrow zone between forest and alpine, it reaches up tall and proud, impervious to the gruelling climate that makes cowering shrubs of other trees.

But all must wait another year, for this season comes down hard. And the will of winter is to erase whatever summer had devised.

Tundra

Porcelain-cold, the November sun dawns in the southeast sky. The ledges, ice-encrusted, layered with sleet from a recent squall, whistle the cold morning wind aside. Rattling down, a slide of rock plunges off the final ledge, seconds passing before the hollow sounds of impact clatter back. Like an apparition of winter itself, white beard bent sideways by the wind, a mountain goat steps to the precipice edge. Looking out across the vast white void, its long belly hair and pantaloons streaming with the ceaseless wind, this strange animal, product of some unfathomable ingenuity, hesitates but a moment; dropping down from step to invisible step along the sheer rock face, fracturing the ice glaze as it goes, it turns a wall and disappears. A nimble, eight-months-old kid follows.

Blinking and twisting in the dull light, the shower of shattered ice clinks softly downward against rock, fading away like the short summers of this place.

But while the wind chants winter, life has made a passage here, and also waits, hidden in seed and root and den.

■ The nanny and her kid have bedded down now, looking across the deep, snowy basin below. Their ledge shines with the first spear of sunlight.

Far below the pass that connects Mount Siyeh to the snow-giants Matahpi and Going-to-the-sun, three male white-tailed ptarmigan emerge from their night’s huddle within a snowbank and step out to peck at an exposed mat of willow. Ptarmigan, the only birds on the winter tundra, wear white plumage in this season, helping to camouflage them in the snow, just as their mottled brown summer plumage makes them difficult to detect among bare rocks. There are few predators here to hunt them now, but they move with habitual slowness; quick movement can be fatal when summer brings numerous eyes to scan the slopes. With legs and feet heavily feathered and sharp claws to scratch for food beneath the snow, the ptarmigan live at truce with winter. When blizzards rage between the peaks, they nestle together in snow dens, beyond the reach of the winds. Ptarmigan hens winter lower in taller willow thickets, but the males prefer to take their winter as high as possible.

Now they crouch behind the wind-deflecting rocks, dozing in the meager warmth of the morning sun.

Near the snowless summit crags, a flash of brown fur zigzags among the rocks. That would be a pika. Only for a moment does it show itself, so quickly does it move.

Also called the rock rabbit, the diminutive pika belongs to the order of hares and rabbits. Resembling a small guinea pig, this sturdy creature spurns hibernation as a way to beat the challenge of winter. Instead, it spends the summer laying in a store of hay for the lean season, spreading cut grass to cure upon the rocks and tending its “haystacks,” on which its survival hangs.

Winter is a great peril to small mammals. Their small bodies, because of a large surface area in relation to volume, retain heat poorly, and their high metabolic fires consume calories quickly. Great amounts of energy are required to sustain an active animal in rough terrain, placing further demands on the animal’s capacity to survive the cold. The pika may need to stack as much as 25 kilos of hay; to keep its furnace burning during winter it will have to fuel its stomach almost hourly.

Small animals of cold climates often show distinctive body adaptations. On the pika the small, rounded ears lie flat along the head, the tail is inconspicuous, the legs are short; heat loss from exposed surfaces is thus reduced. Fur insulates the soles of the pika’s feet while at the same time providing good traction on steep rock faces.

Hidden below these rocks are the hibernating marmots and the sleeping ground squirrels. Beneath the snow the mice, shrews, and pocket gophers struggle on with their lives. But above ground, directly confronting this arctic climate, are the pika, the ptarmigan, and the mountain goat.

A triumph of adaptation, the mountain goat faces the winter day without benefit of either the pika’s den or the ptarmigan’s snow roost.

The nanny and kid descend from their ledge to search out browse at treeline with other members of a loose band—yearlings, young males, other nannies with kids. At the fringes of the band a solitary adult billy only grudgingly associates with other members of his kind; for this is the season of rut.