Rocky Mountain National Park

Winter winds scream at more than 200 miles an hour through gaps in the rocks high atop Tombstone Ridge. It seems impossible that anything could survive in so inhospitable a spot. Yet heroic limber pines, their roots sunk deep into cracks in the rock ridge, continue to wave the banner of life here at the timberline. Majestic in their tortured poses, they are battered, twisted, and sandblasted by the wind, a sculptor that shapes them into its own violent self-portrait.

The timberline, undulating between elevations of 11,000 and 11,500 feet here in Rocky Mountain National Park, is the most dramatic battlefront in life's long struggle to clothe the mountains, a struggle that is the spiritual core of the Rockies. With almost geological deliberation, one seed at a time, the forest creeps upslope.

Although Engelmann spruce and subalpine firs, less pliant than the limber pines, cannot survive by bending with the murderous wind, they have their own way of letting its power shape them into elfinwood, or krummholz (German for "twisted wood"). Some mild, moist summer, a seed may germinate in the shelter of a rock, and a tree may sprout. Any shoots that peek above the rock are sucked dry; but the tree must grow or die, and so it extends itself sideways. Huddled behind the rock, season after season, its trunk and cowering branches add girth; and as it becomes increasingly dwarfish, its own wood begins to shelter new growth. Very gradually, it expands beyond the protection of the rock and joins with other hardy pioneers to form a low front wall that protects the trees behind it and lets them grow a little taller. Someday, another generation of seeds may take root behind other rocks and advance the timberline again.

Dramatic though the timberline struggle is, it is not the true front line of life in the park. Above it are the treeless peaks of more than 60 mountains, as well as several long ridges; during the brief growing season, all but the highest summits are bestrewn with bright wildflowers are carpeted with broad swathes of green. This is the alpine tundra, a rolling, rocky expanse bounded only by the sky above and by dramatic vistas of glacier-sliced cliffs all round about. Here, as on the vast Arctic tundra that covers much of Alaska and northern Canada, plants must be tough if they are to survive. They must tolerate drying winds that would quickly wilt a rose, and temperature shifts that would brown a violet. And yet they are very fragile, any extra stress, even the tramp of one person's foot in the same place as the another's, can kill.

The plants grow low to the ground, out of the main force of the desiccating wind. Like desert plants, they conserve moisture. Many cut their water losses and hold in warmth by wearing furry coats; others, such as the yellow stonecrop, have hard, waxy leaf surfaces. Because plants have but a short time to flourish and bloom on the tundra, late June and part of July, more than one growing season is generally needed to complete a life cycle; annuals have little chance of survival. Snow buttercups, the first blossoms to appear, do not even wait for the snow to melt. By the heat of their own growth, they shove their way up through snowbanks. And though the plants are small, most of them bear large, bright lowers, for they must attract pollinating insects quickly if their seeds are to be spread before August, when winter returns. The tundra's largest blossoms, two to four inches across, are borne by alpine sunflowers; blooming is their last act, after years of storing energy in long, fleshy taproots.

Scurrying among the rocks of the tundra are pikas and yellow-bellied marmots, two creatures with markedly different life-styles. The hyperactive little pikas, short-eared cousins to hares and rabbits, do not hibernate in winter, and so they must spend long, busy summer days gathering food. They spread great quantities of greenery to dry, then store it among the rocks. (Hikers entering pika territory often hear a high-pitched bark of warning; pikas are cranky because they must guard their hay piles against the thievery of their own kind.) Adding to the stress of their existence are the threats of ermine, which can follow pikas through rocky passageways, and prairie falcons, which strike from the sky with great speed and no warning.

The roly-poly, buck-toothed marmots, however, with their quizzical faces and waddling gait, are never busy. Rising sometime after the sun comes up, they stuff themselves at their leisure on the foods they like, sunbathe on warm rocks, take shelter from afternoon thunderstorms, and come out again in the evening to eat more good green herbage. They need not store up anything but fat, for they hibernate all winter, generally losing as much as half of their body weight by spring. Marmots are not much concerned about human intruders, but their sharp whistles warn of serious trouble when a golden eagle soars overhead.