You wipe the sweat out of your eyes with a sap-stiffened glove, clinging tightly with your other hand to the one live branch, thick as a hammer handle, that is keeping you up here and alive, 30 feet or so above the rocky earth, while your boots struggle to balance on twigs and your knees try to grip the tree's little weather-blasted top. Every tree is different, but one thing is constant: Once you've strung your rope around the bushy shoots of the treetop, collecting them all together into one, ideally weight-bearing, anchor, and tied your arborists' knot, when you finally have the holy rope to hold you there, the sweating slows, the spit returns to your dry mouth. Then you can settle your weight against the padded waist strap of your harness, and let your flip rope -- the one you climbed the tree with -- hang free, push back your climbing helmet and look around at the surreally beautiful landscape of Montana's Beartooth Plateau stretching forever in the incandescent September sunlight.

This particular tree is a whitebark pine, heavy with a crop of cones. The crown cones in front of your face are the color of dark rich chocolate, encased in sap that protects them from the furious high-altitude light. In the early morning cold, the sap is hard as refrigerated bubble gum. Later, during the heat of the day, it will drip, clogging carabiners, harness and helmet buckles, pocket-knives. It gums your eyelashes shut and tastes like a primitive soap.

The giant yellow vinyl bag you've dragged through the lower thickets of branches, the one they call "the pig," which is always either hung up below you, or on the wrong side of the tree, or so heavy with cones that you cannot move it at all, is empty now. You tie it off with a simple hitch around a branch that looks stout enough to hold it. The carabiner that holds it to your harness is stuck open with sap. As you twist the cones free and drop them into the pig, they land with hollow thuds that remind you that the day is just beginning. Hours of climbing are ahead of you, hours of stripping a sap-hardened rope through your knot as you work down this tree and the next and the next, hours of hauling bushel bags of cones back to the truck or rally point, hours of cold rain or blazing sun, of fear and danger and the joy of being free under the vast eye of heaven, making good money and, just maybe, helping ensure that this species of tree survives.

I'd worked harvesting cones before that morning in 2009, mostly climbing ponderosa pines around Montana, in the Bitterroot and Sapphire ranges and south of Big Timber, and even plucking, twisting, cutting cones -- thousands of them -- from felled trees piled in the dust and heat of a logging unit in South Dakota's Black Hills. But for anybody who has ever spent a lot of time up high at timber's edge -- skiing peaks, scrambling, climbing, wandering -- the whitebarks have a grandeur beyond that of the mightiest ponderosa, or the stately, disheveled western cedars in their shadowy cathedral, or even the ship's-spar of a western white pine, towering over the rest of the canopy.

The whitebark pine (Pinus albicaulus) is mostly found clinging to the treeline -- more or less the last stop in the life zone -- in a core range that extends from the U.S. Northern Rockies into Canada, and some outlying island populations in Washington, Oregon, California and Nevada. They're the sturdiest, most obstinate of trees, scarred by lightning, sculpted and bonsai'd by centuries of the kind of weather that destroys lesser plants and animals. They inspire reverence in every true mountaineer, simply because they embody what is most powerful about alpine climbing: the ability not just to survive, but to thrive under the harshest conditions that this ruthless part of the planet can dish out. I heard recently from an expert that there is a whitebark pine on Railroad Ridge in Idaho's Sawtooths that is 1,275 years old. Yes, indeed.