In a certain sense that was precisely what had happened, except that the missing ingredient was not a nutrient, it was a fungi. The soil had adequate nutrients, but it turned out that the Douglas fir is incapable of absorbing them without the help of certain symbiotic fungi that live in and around its roots. Once scientists figured it out, discovering the basis of the symbiotic exchange was straightforward. The fungi took in the nutrients from the soil and passed them along to the roots of the fir, which could not absorb them on their own. Then the fir, in return, provided the fungi with carbohydrates, which they were incapable of creating for themselves. The Douglas fir and the fungi, in short, were like the lichens - a plant and a fungi so closely associated in their evolution that there was no meaningful way to make a distinction between the one and the other.   

It is little wonder that this symbiosis had gone undiscovered for so long: The fungi existed as invisible webs of tiny thread-like hyphe that were far too small to be noted by the naked eye and that were disrupted, or even destroyed, by digging. Yet as scientists pursued the mystery of the association the webs involved turned out to be huge - some single individuals covered acres and even square miles. As tall and thick as the fir might grow, they remained the junior partner. As we walked through a giant fir forest, awed by the trees that towered above us, we unknowingly trod on the backs of even larger creatures beneath our feet.   

The fir is far from unique in this association. We now know that many trees are symbiotic, to greater or lesser degree, with subterranean mycorrhizae. But most of them can only form partners with a relatively few species. The fir can associate as a symbiont with as many as 2,000 types of fungi - and this, more than any other aspect of the tree, may explain its dominance in so many ecosystems along the Western coast.   

The mycorrhizae, as the subterranean webs of fungi are called, are as regulated by the rains as the rest of the ecosystem. When the long summer days begin to shorten and afternoon clouds begin to appear, the hyphe beneath the soil begin to form localized mats, called mycelium. As the moisture levels of the soil increases and the temperature drops, some unknown trigger point is reached. Suddenly, with the first season of rain full upon us, the forest floor erupts in mushrooms.   

The fungi share the wet forest floor with all manner of snails, from the common brown tree snail to the more exotic striped and even translucent varieties. Slugs are everywhere, and they love the mushrooms; they can eat even the most poisonous ones with impunity. They generally range from the size of an elongated bean to something the length of a child's index finger. But these common varieties are dwarfed by what many say (slanderously) is the official Oregon critter - the giant banana slug. In the wet ecosystems along the beaches banana slugs can grow to the size of . . . well, a small banana. They give the tourists who overstay the rains a reason to leave.   

Sowbugs and millipedes, which feed on rotting vegetable material, are also plentiful on the forest floor. The bugs are stalked by a dozen species of salamander, newts and tree frogs. One of the frogs - a tiny thing with suction cups at the end of each toe - has the ability to change color. One rainy day, while walking in the forest, I found one on a hazel bush and plucked it off. It was pale green when I found it, but as it clung to the palm of my hand the green rapidly faded and was replaced by the exact color of the human flesh. The frogs, of course, along with the newts and salamanders, are hunted by the huge coast mole and a variety of nonpoisonous snakes. The mole is dinner for the bobcat. The redtailed hawk, who sits silently in the moss-covered upper story of the forest, has a special fondness for snake.   

Autumn is the long season in the Pacific Northwest. The first rains lower the temperature; later, as the day length shortens and the hemisphere cools, the rain temperature remains fairly constant. December rains, as a result, add warmth to the ecosystem and prolong the autumn. Clouds also function to buffer the radiation of heat which, in these northern latitudes, tends to be a major factor in cooling.   

Inevitably, though, the temperature drops. There is some night frost, and then a freeze. The mushrooms taper off and the fog turns cold. Sometimes you can almost feel the ice in it. Occasionally ice may indeed form on exposed surfaces, imparting a glistening varnish to the forest green.   

When there's ice, or a wet snow, Oregonians stay out of the forest. For while ice and snow is beautiful, and rare enough here, the Douglas fir lacks the ability of its high country cousins to shed the snow or bow under the ice. A rind of ice an eighth of an inch thick can add up to many tons of weight in a big tree; a breaking branch high in the tree will fall and break others, which, in falling, will bring down still more. The result is a hail of debris that could easily kill a human being. At such times we can hear the explosions of sound from inside our house. On the rare occasions when there is a significant wet snow in the Willamette Valley, giant fir that have weathered a century and more may come crashing down across roads and power lines.   

The winter solstice, in December, only announces the beginning of the real winter. The days may become longer but the weather is colder. The fungi disappear, along with the slugs, snails and newts. The bobcat scrounges for voles, and grows thin. Down in the valley redtailed hawks sit on fence posts beside the highway, looking wet and hungry.   

Real winter in the Valley usually sums up to six weeks in January and February, and is usually not cold enough to allow me to stoke up the pot-bellied stove without overheating the house. The forest, during this period, is warmer than the yard, because the forest canopy comprises yet another insulating blanket between earth and space. The temperature on our deck hovers in the upper twenties at night, climbing into a foggy 40 or so in the daytime; precipitation remains wet, with only occasional flurries of snow or late-night ice storms. In the night, black ice makes the roads treacherous.   

Though it rains almost every day, sunshine is a mixed blessing. Sunshine in January tends only to come when the jet stream weakens or the ocean weather system falters. This lets the arctic wind howl in over the mountains, bringing us a taste of continental winter. Then the thermometer plummets. Human breath turns to steam. Fingers of ice protrude from the saturated and suddenly frozen ground, reminding us that the Valley of the Willamette occupies a latitude to the north of Toronto and Vladivostok. Now the sky is continental blue, but Oregonians who have been bellyaching about the rain for months now will bemoan their bursting pipes and pray for clouds.   

Even during the coldest nights, though, the soil in the rain forest usually remains unfrozen. A rind of ice may form on the dead leaves on the surface, but it is rarely cold enough, for long enough, for the freeze to penetrate far. A quarter-inch below the surface there is still enough latent heat to allow the metabolism of a few winter-season mushrooms.   

Though it may seem odd to outsiders, many Oregonians think of wintertime as beach weather. The Oregon coastline consists of alternating headlands and beaches, and the surf is punctuated by volcanic stacks and protrusions. This is beautiful enough in the summer, but fog, wind and heavy seas render it all the more haunting and romantic. After Labor Day you can often walk the beaches for hours without seeing another soul.   

If the coast is beautiful in the sunshine it is romantically spectacular in the rain. The trees are greener then, and their gnarly profiles gain character when they are silhouetted against banks of fog. The volcanic cliffs are blacker, set against the flying foam of the sea. The wind whips violently around the lookout at Foulweather Point, banging the flag's lanyard sharply against its metal pole. Hundred mile an hour winds have been recorded there, and it is bitterly cold. But I will never forget the frosty December day that we leaned on the chain link barrier at the cliff's edge to watch a gray whale surface and roll in the heaving green sea a hundred feet below our feet. Later we ate halibut and lobster bisque in the Tidal Raves restaurant, overlooking the churning froth of Depot Bay. Our favorite motel, which has rooms overlooking the sea, has a Christmas special. Every year or so, we take advantage of it.   

In fact, many Oregonians think the coast is best when it's worst - when a violent storm throws itself angrily against the edge of the continent. Then the storm-watchers show up in droves, and it becomes impossible to find a room with a decent view. There is nothing quite so cozy as building a fire in the fireplace and spending the day watching out a picture window while fifty foot waves slam against the rocks and the wind shrieks and howls like the end of time. Once we stood on a bridge parallel to the coast and watched the storm tide work on fifty or sixty huge logs that had somehow washed ashore. The smallest of them was probably thirty feet long and three feet thick, and by the time we got there they had already been worn down to smooth, round, barkless cylinders. Each wave sent them spinning and flying like so many Tinker Toy sticks. Then, as the waves receded, the logs would roll back down toward the surf to meet the next big wave, which would lift them out of the water and set them spinning in the air.   

The next day, as the storm died, we wrapped ourselves in our raingear and walked the beaches, picking up agates and keeping an eye peeled for glass floats from the Japanese sea or chunks of rib and keel from old sailing ships, gone down lifetimes before.   

Ultimately, of course, Oregonians don't yearn for spring any less than their fellow citizens across the Cascades. What they yearn for, though, isn't warmth but sunshine. In February, some parts of the valley may go a week or more without a shadow falling, and by then Oregonians of European ancestry have begun to look like animated marshmallows. A shuttle service to Reno operates out of the Portland Airport, and it prospers in late winter. Hawaii beckons, and Cancun. Most of our friends disappear without warning, reappearing again in two weeks with red skin flaking off their faces.   

We have never felt the need to flee the March rains, perhaps because our mountain valley is blessed with a quirk of weather that other Oregonians can only dream about. For reasons I cannot fathom the local wind patterns that prevail conspire to break up the clouds almost every day between 11 a.m. and 1 p.m. It isn't predictable. It doesn't always clear, and when it does it doesn't always stay clear for two hours. But in the worst of the gloom we rarely go more than two or three days without the sun coming out and setting the rainbows a-twinkle.   

Spring in the Pacific Northwest is a statistical abstraction, building like compound interest -- a decreasing chance of hard freezes and an increasing chance that your spouse will come home with blooming primroses or violets. The days, which are but a few hours long in December, lengthen rapidly. You realize, one day, that it's too warm to light the fireplace. Spring is the sudden insight that the rogue squirrel that's been eating your birdseed and growing fat all winter isn't fat at all. She's pregnant.