Once, when Tara and I were living in eastern Nevada, we went to an outdoor store in Salt Lake City, Utah, because I needed a pair of cross-country ski boots. The young woman who rang us up, finding that we were from Nevada, wondered where we could ski; she seemed to think the whole state—Utah’s neighboring state, I should add—was a giant, sweltering desert. We had to inform her, hopefully without sounding too condescending, that we lived in a valley at 6,500 feet, with mountains more than 10,000 feet high on both sides. At times, we could ski right out our back door.
No, Nevada is not all sweltering desert. Through most of the state, even the valleys are high and, in the winter, quite cold. More than that, though, Nevada is, by some measure, the most mountainous state in the country, with 314 named ranges (that’s 3…1…4, not a typo), 25 of them with peaks over 10,000 feet. (These mountains almost all run north-south, which led to a geologist describing the landscape as “an army of caterpillars marching toward Mexico.”) The high Nevada mountains can be very snowy, and the Snake Range, in the far eastern part of the state, even has a paltry but real glacier.
For Tara and I, one of the great pleasures of living in Nevada is visiting these different mountain ranges, all of them distinctive in one way or another. (Well, that’s an educated assumption—we’ve only been in several dozen ranges, a small fraction of the 314.) Having two small kids has cut way down on our pace of exploration, but this year we managed two trips to an especially intriguing and beautiful range that we’d never visited before, the Santa Rosa Mountains, in north-central Nevada, close to the Oregon border.
Granite Peak, the high point (9,732 ft) in the Santa Rosa Mountains. The rock of this peak formed in the same events that created the granitic plutons of the Sierra Nevada. Thanks to Alan Wallace for that bit of geological history.
One of the most striking things about the Santa Rosas is that, despite having multiple peaks over 9,000 feet high, the range has only two species of conifers. As you drive north up the road from Paradise Valley toward Hinckey Summit, you pass through sagebrush and bitterbrush and, where you might expect pinyon pines and junipers—the “PJ zone” so common in Nevada mountains—you find…more sagebrush, along with some mountain mahogany.
Farther along that road, at Hinckey Summit and points north, you run into dense stands of trees, but they’re not conifers, they’re aspens. My impression is that the stands are especially extensive here, which might be related to the absence of other trees (or, alternatively, could be a trick of the eye caused by that absence). Incidentally, on our trip last week, we hit the aspens at what I consider their peak—not the time of greatest brilliance, but when there’s a wild quilt of different colors, various shades of green, yellow, and orange. The “patches” in the quilt are groups of clones, with the aspens making up each clone sharing a common timing of the shift to fall colors and a common leaf hue.
Patchwork of aspens at Lye Creek campground
An orange clone
On the ridge that runs from Hinckey Summit west to Granite Peak, at an elevation of 9,000 feet or so, you would expect to find three or four kinds of conifers if this were a “typical” Nevada mountain range (which I realize is an oxymoron). However, here you find only a few scattered limber pine, the one moderately common conifer in the Santa Rosas. (The other conifer is western juniper, which is rare.) Unfortunately I didn’t get up high enough to walk among the limber pines—I had to settle for looking at them through binoculars.
Dead limber pine on Granite Peak. Photo by Tara de Queiroz, who made it farther up the mountain than I did.
I was going to try to explain in some depth why there are so few conifers in these mountains, but, in looking into the topic, I realized this would involve a lot of speculation. However, it seems that at least part of the answer is pretty straightforward: Some of the species that might thrive in the Santa Rosas simply haven’t gotten here.
For instance, Douglas-fir and white fir, which are now found in eastern Nevada mountains, do not seem to have been in the Great Basin during most or all of the Pleistocene. The subspecies of these trees that are in eastern Nevada apparently colonized the Great Basin from the east or south, and, for that colonization process to reach the Santa Rosas, seeds would have to jump over numerous arid valleys, from one mountainous “sky island” to another. A similar argument might apply to singleleaf pinyon pine, which colonized the Great Basin from the south in the last 7,000 years, but hasn’t reached this far north (although it may be that the northward spread of this species was slowed or stopped by climate).
To the degree that this argument is right, you could say that the Santa Rosa Mountains (and other Great Basin ranges) are like a volcanic island that had to be populated from elsewhere by some kind of chance dispersal. But the analogy obviously isn’t perfect, because, unlike a newly-formed island, the Santa Rosas were not devoid of life before the Pleistocene, nor were they wiped clean of trees by Pleistocene glaciers. I assume that at some point there were conifer species other than limber pine and western juniper here. So an obvious question is “What happened to those Pleistocene or pre-Pleistocene conifers?” I’ve got little to say about that. I would love to hear if someone else has any insight or information on the subject.
In any case, visiting the Santa Rosas is a great reminder of the uniqueness of Great Basin mountain ranges and how their character is connected to deep biological and geological history. It’s also a great place to see the beauty of aspens, in a pure state, unadulterated by all those conifers!
The Monkey's Voyage 