Campaign 4: Bariloche to Paso El Triana

Coming from Michigan’s Upper Peninsula (U.P.), I thought I was accustomed to wide open spaces and dirt roads. And while it’s true that the U.P. has endless forests pierced by two-tracks, the sheer distances just cannot compare to those you’ll find in Patagonia.

The emptiness of this landscape is difficult to explain. Take a quick gander at satellite images of Patagonia and you’ll see nothing but mind-boggling wilderness. To measure by population density, there are about 1-2 human inhabitants per square kilometer here, compared to just over 7 in the U.P., and a staggering 230 in Germany. All necessities and creature comforts – gasoline, restrooms, agua caliente for yerba mate – are limited to villages, which can be upwards of 200 kilometers apart. If you’re lucky, you might see one or two squat little houses on the roadside, hunkered close to the ground to stay out of the punishing wind. Otherwise it’s a sea of hummocky grass bleached gold by the sun, a landscape so endless and flat that it creates its own optical illusion: watch it for too long and when the car finally stops, it seems like the steppe is still moving.

STEPPE

The pace of life slows a bit when the pavement ends, but the scenery doesn’t change much. All told we spent about 11 hours on dirt roads during this trip, bumping and skidding through the steppe in search of lenga populations. When conducting research in Patagonia, the critical question isn’t always “where are the trees?” – sometimes it’s “where are the roads?” Lenga populations that would be scientifically interesting or useful to sample are often just plain too far off the beaten path to be feasible study sites (unless you happen to have access to a helicopter).

During the previous campaign, we’d hastily decided to double our sampling size in Trevelin, but we hadn’t actually finished the upper or the middle populations, so our first stop was a familiar one. I handed off my usual duties of data recording and taking morphological measurements in favor of wrangling the Milwaukee, and I quickly learned how physically demanding it is to extract hundreds of tree cores (shoutout to my dad for teaching me how to handle electric drills as a child!). Thankfully the horseflies had all dropped dead since the last time I’d been there, but towards the end of our work day it started to snow – unsurprising, I guess, for late summer in the southern Andes.

With our Trevelin sites finally complete, the real road trip began. First south to the town of Gobernador Costa, then two hours down dirt roads through a series of private ranches. We were on the hunt for our second and final eastern xeric population. Xeric, or dry, populations are included in this study for myriad reasons. For one, they’re isolated from the core N. pumilio distribution area, and they likely originated from different glacial refugia (i.e. ice-free locations in past ice ages). Such physical isolation can be a major driver of genetic differentiation. Additionally, the extreme current environmental conditions have probably influenced the local adaptations of these populations, allowing them to survive in irregular habitats. Fringe populations, as they’re also known, are important to include in our work to ensure we’re capturing a large range of intraspecific genetic diversity. They’re also important for the future of the species itself, since these populations might contain genetic variants that will survive under warmer and/or drier climate conditions. Such uniquely adapted genetic variants can also benefit local forestry and conservation-oriented reforestation efforts – for example, foresters can source seeds from these areas and plant forests that may be more resistant to climate change.

Xeric

Herds of wild guanacos (llama-like critters) and Darwin’s rhea (emu-like critters) sprinted away from our truck all morning, mingling with the more familiar domesticated sheep. We stopped to talk to a gaucho who was meandering through the steppe on horseback, miles from the nearest building. We drove further into the steppe, and then, out of seemingly nowhere, a forest appeared. Wedged impossibly into a fold in the golden landscape, it snaked along the shores of a small creek and up the side of a nearby east-facing hill.

Lenga is an economically important species in Argentina, and most of the forests we visited on this campaign had recently been selectively logged. In our xeric population, the standing trees were large-trunked but often vertically stunted, appearing older than they actually were. Although we haven’t yet analyzed the tree cores, a cursory glance in the field showed fairly large annual growth rings in most trees, suggesting rapid growth.

Our final location, Paso El Triana, was 150 kilometers due east of a tiny town called Rio Mayo. We visited this tiny oasis of civilization just long enough to stock up on gasoline, groceries, and a heaping pile of fresh facturas (pastries), then dove back into the wild. Three hours on dirt roads later, we rolled into Aserradero La Rosa, a sprawling sawmill complex perched directly on the Chilean border. The sawmill had a three-bedroom guesthouse, an enormous separate cookhouse dominated by an open fire pit, and (the best part) easily-accessible lenga forests that we could just drive right up to! Ah, luxury.

All the driving meant we were fighting the clock, so we immediately turned on the 4-wheel drive and tore up a haul road into the woods. Although this forest had great road access, our selection of sampling sites is also massively dictated by the terrain. We often have no idea what we’re getting into until we set foot on a site, and once we’re there we have to put an ear to the ground and listen to the landscape. In El Triana, that landscape told us there were two available “extremes” – a humid valley and a forested hilltop, where the trees dripped with old man’s beard.

Back at the ranch, we were greeted by a welcome sight: the indoor hearth in the canteen was filled with a crackling fire and a rack of mutton, being tended by the sawmill owner himself. We sat and talked with him for hours, sharing bottles of wine, smothering spicy homemade chimichurri on everything, and devouring a lemon-and-dulce-la-leche cake. It was easy to relax, knowing that the following field day would be a leisurely one. And for once, the second day actually was relaxing. We’ve generally found more rotten trunks in the lower than the upper populations, which makes tree selection and core extraction more complicated, and this lower site was no different. However, being just a few kilometers from home base meant we could wake up late and share a mate before field work, return to the canteen for lunch, and when we finished we just spent the afternoon  sitting and watching the shadows lengthen over the rolling hills.

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