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.