QUEENSTOWN, NZ. Once again, I was indebted to Kathrin’s driving skills. Already foiled by my inability to drive a car with manual transmission, now I could only sit back as she maneuvered our truck up the four-wheel drive ski lift road. It being austral summer, there wasn’t a speck of snow in sight, but there were plenty of trees. And as usual, we were in search of one species in particular: Douglas fir, which is rapidly becoming a nasty invasive species following its introduction from my North American home.

This site, a few kilometers outside of the city, was perhaps the least remote of the places we’d visit during our research in southern New Zealand. Most of the time, we’re privileged to work in pretty isolated spots: Though my field sites are marked by Douglas-fir plantations, an obvious human modification, they generally lack cell phone reception, paved roads or other humans. I double-check the first aid kit and emergency locator beacon every time I shoulder my pack.

We get off the beaten path particularly quickly in New Zealand because its human population density is exceptionally low–at least, compared to that of the United States (and my home state of New Jersey in particular). Each Kiwi could, in theory, sprawl out over six hectares, or roughly a dozen American football fields. Of course, 71 percent of people live in one of the country’s urban centers, which leaves a whole lot of real estate open to roving ecologists. By comparison, we denizens of the Lower 48–the contiguous United States–squat on just 2.5 hectares per person.

And yet, at the start of every hike, we find the trappings of humanity. Usually it’s a beer bottle or two tossed at the side of the road. (I once spotted the remains of an entire case tucked discretely into the shrubbery.) As we trek uphill, the casual merrymakers drop out, and we encounter only the occasional tramping hut, an overnight bunkhouse for hikers, firewood stacked neatly at its door.

Off-track, signs of human occupation are only indirect: Deer browse here, pine saplings grow there. Both species were deliberate human introductions to the country. Likewise, the absence of moa–the famed giant flightless birds, hunted to extinction around A.D. 1400–and general silence of the forests, whose songbirds have been devastated by non-native rats and possums, reveal human impacts to the trained observer.

Inevitably, our field surveys bring us above the tree line–which is, admittedly, exceptionally low in New Zealand. Even here, out among the tussock grasses with spectacular views of a rugged, untamed landscape, we find wildling conifer seedlings, foreigners sprouting where no native tree could stand.

It’s easy to get depressed here in New Zealand, where so many human-introduced organisms are overrunning the native flora and fauna. But Aotearoa–as the First Peoples call their homeland–is still a land of wildness. It’s still the place where you can hike for days without encountering another human being. It’s still the place where city folk take off for the hills over a weekend and return with fresh venison in their packs. It’s still the place that calls those of us who feel the urge to “get away from it all.”

I love New Zealand for this reason–for the same reason that I loved Alaska when I worked there so many years ago. I’m intoxicated by the knowledge that I am looking out over distant peaks that are rarely–if ever–visited by humans. I don’t consider myself an explorer or trailblazer. I simply like to reach the edge of human civilization and look out over a limitless landscape, as its edges disappear beyond the horizon.

But just because something is out of sight doesn’t mean it’s out of reach.

Last week, the seventh episode of the BBC’s Frozen Planet series aired here in New Zealand. This is the infamous “climate change episode,” once deemed too controversial for American audiences. Sir David Attenborough–we were treated to the British version of the documentary, perhaps as a reward for tolerating British road rules–points out shrinking ice shelves and thinning permafrost, both signs of human impact even at the farthest extremes of our world.

As it warms our poles and mountaintops, climate change will deliver even more untamed wilderness into our hands. Undoubtedly, we will press our advantage, first laying new tracks, before charting opened shipping routes and finally farming thawed soil.

But what of the beer bottle- and cigarette butt-strewn rubble we leave behind? Will this frontier slide inexorably forward as well? Will we call our domination of the Earth complete? And what will it mean for our humanity when we do?

Holly welcomes questions, comments and loans of stick-shift cars for driving lessons at [email protected]. She refuses to master a 4WD though: there are some places she prefers not to reach.