The same rains that fuel the growth of giant trees lay down the conditions for giant fish, as well. The black rock gorges that take away the water also bring us a variety of species of salmon and the steelhead trout. The first heavy rains of Autumn are a signal for them to begin their final migration upstream in search of their spawning grounds, there to produce the next generation and then die. There is a place not far from where we live where we go to watch yard-long fish fight their way up rocky streams that in places are no more than ankle deep. Exhausted, their bodies blackening with approaching death, they slosh out depressions in the sand and gravel to lay their eggs.   

All this in the primordial wet greenness of the forest, thick with fern and moss, and with the plink and splatter of rain dripping from the trees, the bushes, our hats.   

The first season of rain begins with . . . well, rain, of the usual sort, wet drops falling in the traditional fashion, traversing the gap between the bottom of the clouds and the surface of the earth, plinking merrily on the metal vent covers, running in sheets down the roofs and into the gutters, pooling on the driveway. But as the weeks pass and the migration of the salmon begins, the rain becomes a familiar friend. In the process it reveals, as friends do, a deeper character than was first apparent. While it may be said that all rain falls, for example, certain soft rains seem more to . . . well, to caress the earth. There can be something almost thoughtful about a light rain falling on fir. It lacks the urgency of falling things. It is almost exploratory, like an old lover, who has all of autumn to complete the task. At other times a slow rain, fine as talcum powder, will shimmer in the slightest breeze. Sometimes it turns from rain, to drizzle, to mist, to fog, and then back again in the course of an hour. Sometimes the clouds descend into the forest and are impaled there by the treetops and held motionless.   

As the days grow shorter the clouds draw nearer to the earth, transforming the day into a progression of moments and moods. Sometimes they glide in above the mountaintops, like clouds are supposed to do, but as often they curl in around them, following the valleys. Then only the highest ridges are visible, jagged silhouettes set against the whiteness of cloud both above and below them, in the manner of an Asian painting. This transforms the landscape into a different place. Suddenly what we once thought was a solid ridge is revealed by the nestling fog as a rising series of hills, with hollows between. Sometimes the fog hangs thick and motionless, cutting visibility to a few yards and strangely magnifying small sounds, like the fall of an acorn, while blurring out louder ones, like the voice of the raven. Sometimes this fog is slightly restless, and a tree will suddenly take form before your eyes, only to disappear a moment later.   

The sun, though it appears only occasionally, interacts with the prismatic wetness of the land and air to perform acts of pure art. Brilliant shafts of luminescence poking through the canopy of a foggy forest can remind even a skeptic like myself why the human mind requires the existence of God. At other times the fog lifts, and there is a gap in the clouds, and rainbows grow in great chromatic arches between the verdant hills. The arches of color are so sharply focused, so substantive, so close, that visitors will often extend a hand and take an involuntary step forward, as if to touch them. Then the sun is gone again, and with it the rainbows.   

Sometimes, when the clouds draw close, the rain is not even rain. The forest is simply pregnant with water. It condenses on every branch and fir needle, running down and collecting in blobs that hang there, in precarious suspension, at the tip of every drooping surface. In the dimness of evening these droplets of dew sometimes collect the only light that is left and radiate it back, giving the forest a mysterious inner glow. Meanwhile, moisture accumulates on eyeglasses, eyebrows, and beards. One walks carefully, for merely touching a tree, or brushing against a witch hazel, will trigger a brief but furious downpour.   

Wisps of fog, meanwhile, move silently through the trees, defining the separate branches and investing them with the layered beauty of Japanese watercolors. Like petticoats, the fog conceals to reveal. In one instant you are alone in the forest and the next, as the fog shifts, you are only a few yards from a majestic black-tailed buck with six-point antlers. He stares back, for a moment, and then is gone in a series of crashing leaps that carry through the fog until he is far, far away. A bobcat raises her young not far from our house, but though we will find her territorial scratches in the earth we never see her in the flesh -- not, at least, in the summertime. But the fog emboldens her, and in early November we will see her trotting nonchalantly across the slope below our picture windows. Even coyotes are more approachable, now that they have the fog to melt into if they so desire. Once, in the foggy forest, a great white-headed eagle glided onto a branch not twenty feet away from me and sat there for a time preening her feathers before lazily extending her wings and disappearing once more into the fog.   

We will see the horned owl in the daytime, now, its great rubbery shape appearing without warning out of the gray-white mists and then immediately disappearing again with a liquid flow of wing. The vultures have gone south, and the goldfinches have also left, but the companionable pine siskins have replaced them. They follow us through the forest. One may light on the thin branch of a snowberry bush, tilt its head, and seem to inquire cheerfully of our health.   

The rains bring a dusky darkness to the forest, a gloom that, paradoxically, contributes to stark contrasts between cloudbank and the arm-like reach, say, of an oak limb, clothed with the ghostly green lace of lichens. We have cut paths through the forest and we walk them daily, noting the changes that come with each season. The autumn fog accents the vertical alignment of the tree trunks against the lateral spread of branches.   

In the rain, the forest takes on a rich perfume that exhilarates: the dog tears through the bare understory with his tail up and his wonderful canine nose skimming the ground. I have more trouble identifying what I'm smelling . . . the human nose, by comparison, is a blunt instrument. I think there is a base of musk and mildew, layered over with myriad unidentifiable wet odors that surely smelled no different when giant lizards crashed through forests of towering moss and fern. Whatever the smell, it is primordial, and though I don't recognize it consciously, something in my heart knows exactly what it is. And I, like the dog, feel a heightened excitement.   

Of all the daughters of the earth, the Douglas fir is one of the most awesome. It grows from Mexico to Canada, and in those stands where the woodsman's axe has not fallen recently the trees are so tall and straight that they send the mind skittering backwards to long forgotten botany lessons. What is a tree?   

The answer, at a technical level, is straightforward. Annual plants are limited in height by how far they can grow in a single season. A tree is a plant which has evolved to nurture each generation on the cellulose skeletons of its ancestors. This use of its own dead allows it to climb higher than annual plants, and therefore hog the sunshine.   

Yet nothing is quite as it appears. On the one hand a tree is a thin scum of cambium, a layer of a few cells around a dead spike, secreting corky bark on the outer side and entombing its own dead on the inside. This is very prosaic. But the tree is also like a civilization, in which the living also build on the work of previous generations. It is all both very simple and very complicated. I move through the forest, and the forest moves through me. The fir tree reaches high, into the foggy sky, but its roots weave a complicated bond with the earth.   

And, from among those roots, with the first soaking rains come the mushrooms.   

This fruit of the rain has been sought after and even worshipped as long as human tradition can trace. Oregon is especially productive, and the fall fruiting brings thousands of gatherers into the woods. Some old Oregon families have gathered in the same woods for so many years that they consider the mushrooms there to be theirs; at the same time, each year brings an increased number of newcomers who collect for commercial buyers. Species of king boletes, golden chantrelles, brown morels and pure white matsutakes are so valuable that they are reputed to have provoked savage gun battles between commercial collectors on the slopes of the Cascades. A single giant matsutake mushroom is said to have sold for $600, though most experienced gatherers are lucky to make $75 to $100 a day. Restaurants in mushroom country often put up signs begging customers to leave their weapons in their cars.   

Commerce aside, amateur mushroom collecting in Oregon is almost as serious a pastime as, say, white-water rafting - and it can be at least as dangerous. When I first arrived here I briefly considering joining the fun, but my enthusiasm dwindled when I heard reports of mushroom gatherers whose families died after eating what turned out to be the wrong species of, say Amantia. Many of the deaths, I am told, are among immigrants from Southeast Asia, where the mushrooms look the same as they do here . . . but, unfortunately, are not. Most of the rest come from people in search of the fabled, hallucinogenic "magic mushrooms." Unfortunately these little brown mushrooms (or LBBs, as they are sometimes called) are very difficult to distinguish from other LBBs that will induce a much more permanent trip.   

But one doesn't need to eat mushrooms to enjoy them. They are in effect the flowers of the Autumn, a wonderment of size, shape and color that pops up out of the forest floor almost as soon as the tourists leave.   

Exactly what appears, and the color it shows, seems to depend on the year and conditions. This year, for instance, the forest floor was thick with Russula xerampelina, some of which stood eight inches tall and had great copper-colored caps as large as a salad plate. The caps were concave, so that water could collect in them. Meanwhile, a line of bright yellow mushrooms popped up along the path to the barn while a minion of fat, ghostly white mushrooms appeared near the woodpile, little heaps of half-decayed wood chips perched precariously on their caps. For several years running a fifty- foot-wide fairy ring emerged in the far corner of the yard, sending up fist-sized mushrooms around its perimeter. The first year they were crimson red. The second they were international orange. The third year they were black with red and yellow spots. The fourth year . . . well, the fourth year they disappeared, and never came back. A very woody species, Phaeolus schweinitzii, sprouts up each year near the intersection of two of our forest paths. It presents like a stalagmite, or a cypress knee; it is bright yellow-orange, and it may grow to ten inches high. Then it slowly turns black and, over the next few years, crumbles back into earth.   

Many generations of people have harvested and enjoyed this fruit of the rain, and forests like ours were famous for what they produced. But it was only in our lifetime that the significance of the mushrooms became apparent.   

The story, as it was told to me by a forest service mycologist, involved a Christmas tree farmer who happened to plant a new crop of seedlings in a field that had been fumigated to kill a plant pathogen. The farmer put the seedlings into this sterile soil, fertilized them, and stood back to watch them grow. Oregon, as one might imagine, is a great place to grow Christmas trees.   

But not this field, not this time. The seedlings just sat there. A year later, they were still seedlings. A year after that, despite the addition of fertilizer, they were not much taller than they had been originally.   

If this was a source of great chagrin to the farmer it tended to provoke curiosity in his neighbors, and by and by a few scientists got interested as well. Clearly, there was something these plants lacked. But what was it? The farmer tested the soil, and at least according to the book it had everything the trees needed.   

Then, in random parts of the field, something changed. A few individual seedlings suddenly sent strong leaders up toward the sun. Then the seedlings around those seedlings began to grow, albeit a bit more slowly. And then the seedlings around those began to grow, until finally the quiescent field was punctuated with expanding lush humps of growth. It looked almost like someone had danced through the field, randomly throwing out handfuls of some critical but unknown fertilizer.