فصل 15کتاب: قدم زدن در جنگل / فصل 15
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Once, aeons ago, the Appalachians were of a scale and majesty to rival the Himalayaspiercing, snow-peaked, pushing breathtakingly through the clouds to heights of four miles or more. New Hampshire’s Mount Washington is still an imposing presence, but the stony mass that rises from the New England woods today represents, at most, the stubby bottom one-third of what was ten million years ago.That the Appalachian Mountains present so much more modest an aspect today is because they have had so much time in which to wear away. The Appalachians are immensely old–older than the oceans and continents (at least in their present configurations), far, far older than most other mountain chains, older indeed than almost all other landscape features on earth. When simple plants colonized the land and the first creatures crawled gasping from the sea, the Appalachians were there to greet them.
Something over a billion years ago, the continents of earth were a single mass called Pangaea surrounded by the lonely Panthalas-san Sea. Then some unexplained turmoil within the earth’s mantle caused the land to break apart and drift off as vast asymmetrical chunks. From time to time over the ages since–three times at least–the continents have held a kind of grand reunion, floating back to some central spot and bumping together with slow but crushing force. It was during the third of these collisions, starting about 470 million years ago, that the Appalachians were first pushed up (like a rucked carpet, as the analogy nearly always has it). Four hundred seventy million years is a span pretty well beyond grasping, but if you can imagine flying backwards through time at the rate of one year per second, it would take you about sixteen years to cover such a period. It’s a long time.
The continents didn’t just move in and out from each other in some kind of grand slowmotion square dance but spun in lazy circles, changed their orientation, went on cruises to the tropics and poles, made friends with smaller landmasses and brought them home.
Florida once belonged to Africa. A corner of Staten Island is, geologically, part of Europe.
The seaboard from New England up to Canada appears to have originated in Morocco.
Parts of Greenland, Ireland, Scotland, and Scandinavia have the same rocks as the eastern United States–are, in effect, ruptured outposts of the Appalachians. There are even suggestions that mountains as far south as the Shackleton Range in Antarctica may be fragments of the Appalachian family.
The Appalachians were formed in three long phases (or orogenies, as geologists like to call them) known as the Taconic, Acadian, and Alleghenian. The first two were essentially responsible for the northern Appalachians, the third for the central and southern Appalachians. As the continents bumped and nudged, sometimes one continental plate would slide over another, pushing ocean floor before it, reworking the landscape for 150 miles or more inland. At other times it would plunge beneath, stirring up the mantle and resulting in long spells of volcanic activity and earthquakes. Sometimes the collisions would interleave layers of rock like shuffled playing cards.
It is tempting to think of this as some kind of giant continent-sized car crash, but of course it happened with imperceptible slowness. The proto-Atlantic Ocean (sometimes more romantically called lapetus), which rilled the void between continents during one of the early splits, looks in most textbook illustrations like a transitory puddle–there in Fig.
9A, vanished in Fig. 9B, as if the sun had come out for a day or so and dried it up–yet it existed far longer, hundreds of millions of years longer, than our own Atlantic has. So it was with the formation of mountains. If you were to travel back to one of the mountainbuilding phases of the Appalachians, you wouldn’t be aware of anything geologically grand going on, any more than we are sensible now that India is plowing into Asia like a runaway truck into a snowbank, pushing the Himalayas up by a millimeter or so a year.And as soon as the mountains were built, they began, just as ineluctably, to wear away. For all their seeming permanence, mountains are exceedingly transitory features.
In Meditations at 10,000 Feet, writer and geologist James Trefil calculates that a typical mountain stream will carry away about 1,000 cubic feet of mountain in a year, mostly in the form of sand granules and other suspended particles. That is equivalent to the capacity of an average-sized dump truck–clearly not much at all. Imagine a dump truck arriving once each year at the base of a mountain, filling up with a single load, and driving off, not to reappear for another twelve months. At such a rate it seems impossible that it could ever cart away a mountain, but in fact given sufficient time that is precisely what would happen. Assuming a mountain 5,000 feet high with 500,000 million cubic feet of mass–roughly the size of Mount Washington–a single stream would level it in about 500 million years.
Of course most mountains have several streams and moreover are exposed to a vast range of other reductive factors, from the infinitesimal acidic secretions of lichen (tiny but relentless!) to the grinding scrape of ice sheets, so most mountains vanish very much more quickly–in a couple of hundred million years, say. Right now the Appalachians are shrinking on average by 0.03 millimeters per year. They have gone through this cycle at least twice, possibly more–rising to awesome heights, eroding away to nothingness, rising again, each time recycling their component materials in a dazzlingly confused and complex geology.
The detail of all this is theory, you understand. Very little of it is more than generally agreed upon. Some scientists believe the Appalachians experienced a fourth, earlier mountain-building episode, called the Grenville Orogeny, and that there may have been others earlier still. Likewise, Pangaea may have split and reformed not three times but a dozen times, or perhaps a score of times. On top of all this, there are a number of lapses in the theory, chief of which is that there is little direct evidence of continental collisions, which is odd, even inexplicable, if you accept that at least three continents rubbed together with enormous force for a period of at least 150 million years. There ought to be a suture, a layer of scar tissue, stretching up the eastern seaboard of the United States.
I am no geologist. Show me an unusual piece of grey wacke or a handsome chunk of gabbro and I will regard it with respect and listen politely to what you have to say, but it won’t actually mean anything to me. If you tell me that once it was seafloor ooze and that through some incredible sustained process it was thrust deep into the earth, baked and squeezed for millions of years, then popped back to the surface, which is what accounts for its magnificent striations, its shiny vitreous crystals, and flaky biotate mica, I will say, “Goodness!” and “Is that a fact!” but I can’t pretend that anything actual will be going on behind my game expression.
Just occasionally am I permitted an appreciative glimpse into the wonder that is geology, and such a place is the Delaware Water Gap. There, above the serene Delaware River, stands Kittatinny Mountain, a wall of rock 1,300 feet high, consisting of resistant quartzite (or so it says here) that was exposed when the river cut a passage through softer rock on its quiet, steady progress to the sea. The result in effect is a cross-section of mountain, which is not a view you get every day, or indeed anywhere else along the Appalachian Trail that I am aware of. And here it is particularly impressive because theexposed quartzite is arrayed in long, wavery bands that lie at such an improbably canted angle–about 45 degrees–as to suggest to even the dullest imagination that something very big, geologically speaking, happened here.
It is a very fine view. A century or so ago people compared it to the Rhine and even (a little ambitiously, I’m bound to say) the Alps. The artist George Innes came and made a famous painting called “Delaware Water Gap.” It shows the river rolling lazily between meadowy fields dotted with trees and farms, against a distant backdrop of sere hills, notched with a V where the river passes through. It looks like a piece of Yorkshire or Cumbria transplanted to the American continent. In the 1850s, a plush 250-room hotel called Kittatinny House rose on the banks of the river and was such a success that others soon followed. For a generation after the Civil War, the Delaware Water Gap was the place to be in summer. Then, as is always the way with these things, the White Mountains came into fashion, then Niagara Falls, then the Cats-kills, then the Disneys. Now almost no one comes to the Water Gap to stay. People still pass through in large numbers, but they park in a turnout, have a brief appreciative gaze, then get back in their cars and drive off.
Today, alas, you have to squint, and pretty hard at that, to get any notion of the tranquil beauty that attracted Innes. The Water Gap is not only the nearest thing to spectacle in eastern Pennsylvania but also the only usable breach in the Appalachians in the area of the Poconos. In consequence, its narrow shelf of land is packed with state and local roads, a railway line, and an interstate highway with a long, unimaginative concrete bridge carrying streams of humming trucks and cars between Pennsylvania and New Jersey–the whole suggesting, as McPhee neatly put it in In Suspect Terrain, “a convergence of tubes leading to a patient in intensive care.”
Still, Kittatinny Mountain, towering above the river on the New Jersey side, is a compelling sight, and you can’t look at it (at least I couldn’t, at least not this day) without wanting to walk up it and see what is there. I parked at an information center at its base and set off into the welcoming green woods. It was a gorgeous morning–dewy and cool but with the kind of sunshine and sluggish air that promises a lot of heat later on–and I was early enough that I could get almost a full day’s walk in. I had to get the car home to New Hampshire by the following day, but I. was determined to get at least one decent walk in, to salvage something from the catastrophe that was this trip, and luckily I seemed to have chosen well. I was in the midst of several thousand acres of exquisitely pretty woodlands shared jointly by Worthington State Forest and the Delaware Water Gap National Recreation Area. The path was well maintained and just steep enough to feel like healthful exercise rather than some kind of obsessive torture.
And here was a final, joyful bonus: I had excellent maps. I was now in the
cartographically thoughtful hands of the New York-New Jersey Trail Conference, whose maps are richly printed in four colors, with green for woodland, blue for water, red for trails, and black for lettering. They are clearly and generously labeled and sensibly scaled (1:36,000), and they include in full all connecting roads and side trails. It is as if they want you to know where you are and to take pleasure in knowing it.
I can’t tell you what a satisfaction it is to be able to say, “Ah! Dunnfield Creek, I see,”
and, “So that must be Shawnee Island down there.” If all the AT maps were anything as good as this, I would have enjoyed the experience appreciably more–say, 25 percentmore. It occurred to me now that a great part of my mindless indifference to my surroundings earlier on was simply that I didn’t know where I was, couldn’t know where I was. Now at last I could take my bearings, perceive my future, feel as if I was somehow in touch with a changing and knowable landscape.
And so I walked five thoroughly agreeable miles up Kittatinny to Sunfish Pond, a very comely forty-one-acre pond surrounded by woods. Along the way, I encountered just two other people–both day hikers–and I thought again what a stretch it is to suggest that the Appalachian Trail is too crowded. Something like thirty million people live within two hours’ drive of the Water Gap–New York was just seventy miles to the east, Philadelphia a little bit more to the south–and it was a flawless summer’s day, yet the whole of this majestic woods belonged to just three of us. For northbound hikers Sunfish Pond is something of a glorious novelty, since nowhere south of here will you find a body of water on a mountaintop. It is in fact the first glacial feature northbound hikers come across.
During the last ice age, this was about as far as the ice sheets got. The farthest advance in New Jersey was about ten miles south of the Water Gap, though even here, where the climate would let it go no farther, it was still at least 2,000 feet thick.
Imagine it–a wall of ice nearly half a mile high, and beyond it for tens of thousands of square miles nothing but more ice, broken only by the peaks of a very few of the loftiest mountains. What a sight that must have been. And here is a thing that most of us fail to appreciate: we are still in an ice age, only now we experience it for just part of the year.
Snow and ice and cold are not really typical features of earth. Taking the long view, Antarctica is actually a jungle. (It’s just having a chilly spell.) At the very peak of the last ice age 20,000 years ago, 30 percent of the earth was under ice. Today 10 percent still is.
There have been at least a dozen ice ages in the last two million years, each lasting about 100,000 years. The most recent intrusion, called the Wisconsinian ice sheet, spread down from the polar regions over much of Europe and North America, growing to depths of up to two miles and advancing at a rate of up to 400 feet a year. As it soaked up the earth’s free water, sea levels fell by 450 feet. Then, about 10,000 years ago, not abruptly exactly but near enough, it began to melt back. No one knows why. What it left in its wake was a landscape utterly transformed. It dumped Long Island, Cape Cod, Nantucket, and most of Martha’s Vineyard where previously there had just been sea, and it gouged out the Great Lakes, Hudson Bay, and little Sunfish Pond, among much else. Every foot of the landscape from here on north would be scored and scarred with reminders of glaciation– scattered boulders called erratics, drumlins, eskers, high tarns, cirques. I was entering a new world.
No one knows much of anything about the earth’s many ice ages–why they came, why they stopped, when they may return. One interesting theory, given our present-day concerns with global warming, is that the ice ages were caused not by falling temperatures but by warming ones. Warm weather would increase precipitation, which would increase cloud cover, which would lead to less snow melt at higher elevations. You don’t need a great deal of bad weather to get an ice age. As Gwen Schultz notes in Ice Age Lost, “It is not necessarily the amount of snow that causes ice sheets, but the fact that snow, however little, lasts.” In terms of precipitation, she observes, Antarctica “is the driest large area on Earth, drier overall than any large desert.”
Here’s another interesting thought. If glaciers started reforming, they have a great deal more water now to draw on–Hudson Bay, the Great Lakes, the hundreds of thousands oflakes of Canada, none of which existed to fuel the last ice sheet–so they would grow very much quicker. And if they did start to advance again, what exactly would we do? Blast them with TNT or maybe nuclear warheads? Well, doubtless we would, but consider this.
In 1964, the largest earthquake ever recorded in North America rocked Alaska with 200,000 megatons of concentrated might, the equivalent of 2,000 nuclear bombs. Almost 3,000 miles away in Texas, water sloshed out of swimming pools. A street in Anchorage fell twenty feet. The quake devastated 24,000 square miles of wilderness, much of it glaciated. And what effect did all this might have on Alaska’s glaciers? None.
Just beyond the pond was a side trail, the Garvey Springs Trail, which descended very steeply to an old paved road along the river, just below a spot called Tocks Island and which would take me in a lazy loop back towards the visitor center where I had left the car. It was four miles and the day was growing warm, but the road was shaded and quiet-I saw only three cars in an hour or so–so it was a pleasant stroll, with restful views of the river across overgrown meadows.
By American standards, the Delaware is not a particularly imposing waterway, but it has one almost unique characteristic. It is nearly the last significant undammed river in the United States. Now this might seem an inestimable virtue–a river that runs as nature planned it. However, one consequence of its unregulated nature is that the Delaware regularly floods. In 1955, as Frank Dale notes in his excellent book Delaware Diary, there was a flood that even now is remembered as “the Big One.” In August of that yearironically at the height of one of the most severe droughts in decades–two hurricanes hit North Carolina one after the other, disrupting and enlivening weather all up and down the East Coast. The first dumped ten inches of rain in two days on the Delaware River Valley.
Six days later the valley received ten inches in less than twenty-four hours. At a place called Camp Davis, a holiday complex, forty-six people, mostly women and children, took refuge from the rising flood waters in the camp’s main building. As the waters rose, they fled first upstairs and then into the attic, but to no avail. Sometime in the night a thirtyfoot wall of water came roaring through the valley and swept the house away. Amazingly, nine people survived.
Elsewhere, bridges were being brushed aside and riverside towns inundated. Before the day was out, the Delaware River would rise forty-three feet. By the time the waters finally receded, 400 people were dead and the whole of the Delaware Valley was devastated.
Into this gooey mess stepped the U.S. Army Corps of Engineers, with a plan to build a dam at Tocks Island, very near where I was walking now. The dam, according to the Corps’ plan, would not only tame the river but allow the creation of a new national park, at the heart of which would be a recreational lake almost forty miles long. Eight thousand residents were moved out. It was all done very clumsily. One of the people evicted was blind. Several farmers had only parts of their land bought, so that they ended up with farmland but no house or a farmhouse but no land. A woman whose family had farmed the same land since the eighteenth century was carried from her house kicking and bellowing, to the delight of newspaper photographers and film crews.
The thing about the Army Corps of Engineers is that they don’t build things very well. A dam across the Missouri River in Nebraska silted up so disastrously that a noisome ooze began to pour into the town of Niobrara, eventually forcing its permanent abandonment.
Then a Corps dam in Idaho failed. Fortunately it was in a thinly populated area and therewas some warning. Even so, several small towns were washed away and eleven people lost their lives. But these were relatively small dams. Tocks Dam would have held one of the largest artificial reservoirs in the world, with forty miles of water behind it. Four substantial cities – Trenton, Cam-den, Wilmington, and Philadelphia – and scores of smaller communities stood downstream. A disaster on the Delaware would truly be a disaster.
And here was the nimble Army Corps of Engineers planning to hold back 250 billion gallons of water with notoriously unstable glacial till. Besides that there were all kinds of environmental worries – that salinity levels below the dam would rise catastrophically, for example, devastating the ecology lower down, not least the valuable oyster beds of Delaware Bay.
In 1992, after years of growing protests that spread far beyond the Delaware Valley, the dam plan was finally put on hold, but by this time whole villages and farms had been bulldozed. A quiet, remote, very beautiful farming valley that had not changed a great deal in 200 years was lost forever. “One beneficial result of the [canceled] project,” notes the Appalachian Trail Guide to New York and New Jersey, “was that the land acquired by the federal government for the national recreation area has provided the Trail with a protected corridor.”
To tell you the truth I was getting a little wearied of this. I know the Appalachian Trail is supposed to be a wilderness experience, and I accept that there are countless places where it would be a tragedy for it to be otherwise, but sometimes, as here, the ATC seems to be positively phobic about human contact. Personally, I would have been pleased to be walking now through hamlets and past farms rather than through some silent “protected corridor.”
Doubtless it is all to do with our historic impulse to tame and exploit the wilderness, but America’s attitude to nature is, from all sides, very strange if you ask me. I couldn’t help comparing my experience now with an experience I’d had three or four years earlier in Luxembourg when I went hiking with my son for a magazine assignment. Luxembourg is a much more delightful place to hike than you might think. It has lots of woods but also castles and farms and steepled villages and winding river valleys– the whole, as it were, European package. The footpaths we followed spent a lot of time in the woods but also emerged at obliging intervals to take us along sunny back roads and over stiles and through farm fields and hamlets. We were always able at some point each day to call in at a bakery or post office, to hear the tinkle of shop bells and eavesdrop on conversations we couldn’t understand. Each night we slept in an inn and ate in a restaurant with other people. We experienced the whole of Luxembourg, not just its trees. It was wonderful, and it was wonderful because the whole charmingly diminutive package was seamlessly and effortlessly integrated.
In America, alas, beauty has become something you drive to, and nature an either/or proposition–either you ruthlessly subjugate it, as at Tocks Dam and a million other places, or you deify it, treat it as something holy and remote, a thing apart, as along the Appalachian Trail. Seldom would it occur to anyone on either side that people and nature could coexist to their mutual benefit–that, say, a more graceful bridge across the Delaware River might actually set off the grandeur around it, or that the AT might bemore interesting and rewarding if it wasn’t all wilderness, if from time to time it purposely took you past grazing cows and tilled fields.
I would have much preferred it if the AT guidebook had said: “Thanks to the
Conference’s efforts, farming has been restored to the Delaware River Valley, and the footpath rerouted to incorporate sixteen miles of riverside walking because, let’s face it, you can get too much of trees sometimes.”
Still, we must look on the bright side. If the Army Corps of Engineers had had its foolish way, I’d have been swimming back to my car now, and I was grateful at least to be spared that.
Anyway, it was time to do some real hiking again.
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