My first memorable foray above treeline was a visit to Colorado in the mid-1990s. My uncle, a true wildman, picked pre-teen me up at the Denver airport and drove directly to the top of Mount Blue Sky (then called Mount Evans) at 14,272 feet.

I climbed out of the back seat, admired the dappled carpet of high alpine wildflowers, lichens and brilliant red succulents and promptly vomited all over my Adidas Shell Tops while enviably acclimated coyotes laughed at me from the ravine below. Where was all the air?

It was terrible, and it was gorgeous.  I wanted a ginger ale, but I also wanted more time above the trees.

A decade later, I had my first foray above alpine treeline that wasn’t powered by fossil fuels, but instead by Oreos and ill-advised determination. Considerably more difficult than cruising in my uncle’s Toyota, I rode my bike up Trail Ridge Road in Rocky Mountain National Park, peaking over 12,000 feet and again desperately wishing for more oxygen (though at least I managed to hold onto my breakfast this time).

It was worth it for the bugling elk and also for the descent, one knee almost to the pavement on the tight switchbacks, recklessly fast. (Sorry, Mom!)

When I moved to New Hampshire in my 30s, I was shocked to discover that this little Northeast state had its own share of stunning alpine zones, despite its highest point being a mere 6,288 feet. I expected the treeline to begin somewhere above 11,000 feet and be accompanied by shortness of breath and premature exhaustion, but instead I found it much lower. I could admire 100-mile views in every direction, immerse myself in colorful arrays of mountain avens and diapensia and all the while, fill my lungs at my leisure. So much oxygen -- a delicacy! It was practically air soup!

I learned that the altitude of alpine treelines varies greatly. Lingering snowpack is a primary reason trees can’t grow, so higher latitudes tend to have lower treelines. But wind, steep slopes, soil composition and availability of cold-hardy species all matter. In Colorado’s Rocky Mountain National Park, the trees give up around 12,000 feet, but 1,000 miles north in Montana’s Glacier National Park, they quit a full vertical mile lower.

In Acadia National Park in Maine, the transitional zone of stunted, wind-shaped trees called krummholz -- German for “crooked wood” -- begins a mere 1,000 feet above the raging sea because of brutal winter storms. By contrast, on Hawaii’s lush, warm islands, where one might expect a very high treeline, trees suited to grow at high elevations simply haven’t evolved (or been introduced), so the timberline is at a surprisingly low 9,800 feet.

In most of New England, trees naturally taper off somewhere above 4,000 feet, but our dear Mount Monadnock is a unique exception, curiously treeless for hundreds of feet below her 3,165-foot summit. Considerably lower in elevation and further south than Washington and Katahdin, and with a gentler climate, one would expect Monadnock to be a forested peak.

And, in fact, that’s what she used to be. Mount Monadnock’s summit once sported a rich forest of red spruce. Seeking to open up pasture and farmland in the early 1800s, ambitious settlers set fire to her slopes. While this did create more space for sheep, it also removed vegetation that held the soil in place on the hard, metamorphic rock. Wind and rain quickly eroded the soil, and remaining trees toppled.

Legend, corroborated by the writings of Henry David Thoreau, suggests that the upturned root masses and fallen timber created the perfect protected home for wolves, who made regular meals of the livestock and retreated to the mountain thicket for cover. The furious shepherds were desperate to protect their livelihoods and – so goes the story – lit the summit ablaze again.

Whatever the true cause of the fire, the summit of downed, dry timber was ravaged by flames for days. The wolf-sheltering thicket was destroyed, along with any remaining trees and underbrush. With the topsoil fully blown away, Monadnock’s summit has remained bare ever since.

The ecology above this low, artificial treeline differs somewhat from true alpine zones elsewhere in New England. Pockets of krummholz and even full-growth groves persist, especially in hollows and sheltered coves where soil has reaccumulated. But some wildflowers usually found at much-higher elevations, like Labrador tea and mountain cranberry, have made their way to Monadnock’s upper flanks, so watch your step! Springtime meadows of cottongrass dance in the wind like exuberant fairies.

Though Monadnock’s stone face may seem lifeless at first glance, many creatures call it home. The wolves are long gone, but red foxes still hunt for small rodents among the rocks. On a summer day, after the trail climbs above the hermit thrush symphony of the hardwoods, hikers can expect to be serenaded by white-throated sparrows and cackled at by ravens.

Crickets and the gentle hoot of a barred owl provide the evening soundtrack. Even in winter, dark-eyed juncos hop around the summit. Perhaps most surprisingly, come spring, vernal pools on the craggy, windblown summit are full of wriggling tadpoles!

Though these special places above treeline differ widely, they all share a feel. There’s something wonderfully alien about venturing into this harsh, open landscape. Life is just different there, and the views tend to be remarkable.

Emma Kluge is an educator and naturalist at Harris Center for Conservation Education in Hancock who loves to explore the trails and back roads of North America’s wildernesses.