So why aren't there Pines in the Wasatch?

So, having completed the review of Wasatch PLT’s, the obvious question presents itself: Where are all the Pines? Seriously, in any direction you go from the Wasatch, there are plenty of Pines. For example:

East: Lodgepole Pine, Pinus contorta, is all over the Uintas, and start up a mere 25-30 minutes drive East of Park City. Ponderosa, Pinus ponderosa, is common on the Southern drainages of the Eastern half of the range (although the numerous Ponderosas lining Mirror Lake Highway East of Kamas are all planted, mostly back in the 1930’s.) Continuing East there’s plenty of pine clear to Denver, and in fact I lived in a Ponderosa forest West of Denver before coming to Utah.

Tangent: These are the most “confounding” pines for me in a sense. Lodgepoles are all over the place in the Eastern Uintas, so close to the Wasatch, and in a place where the climatic conditions seem pretty much identical. I raced right through here yesterday on the Mirror Lake Highway, from Evanston, WY to Kamas, UT as part of the brutal 170 mile Tour de Park City. It was a hot day, and on the long climb up Bald Mountain, as we entered the Lodgpole forest, the slightly cooler temps and warm, wonderful piny smell were a welcome diversion.

Nested Tangent: The smell of pines on a warm day is one of my favorite smells, and worth a separate, future post. Besides, I need another post about smell.

Return-to-Main-Tangent: Oh and how did I do in the race, you ask? I kicked ass, coming in 3^rd in the Cat 4’s, continuing my 3^rd-place winning streak in the 4’s as well as my streak of using this mostly botany-focused blog to brag about my racing exploits.

North: Lodgepole, Limber, and Whitebark Pines are plentiful all over Wyoming at altitude. The Wind Rivers, the Tetons, Yellowstone and the country all around Jackson and the Snake River are all great examples. Sun Valley and Challis area are loaded with Ponderosas.

South: Once you get down onto the Markagunt (North edge of Zion) and Paunsagunt (Byrce) plateaus there are pines everywhere. The Red Canyon area of the Paunsagunt Plateau is a wonderful mixed Pine forest, featuring Bristlecone, Limber and Ponderosa Pine.

West: Even in the isolated Great Basin ranges of the West Desert and into Nevada Pines are common. The Ruby Mountains outside of Elko feature extensive Whitebark and Limber Pine woodlands, and even the Deep Creeks has a sizable stand of Ponderosa. And of course Singleleaf Pinon , Pinus monophylla, is common on the lower slopes of the same ranges and well as in countless lower ranges.

So why aren’t there Pines in the Wasatch?

Well, first off there are. But the ones you’re likeliest to see are planted. And those are the Ponderosas at several locations in Big Cottonwood Canyon. But there’s one apparently-old-growth Ponderosa growing on the North slope of the canyon, about 5 miles up the road, located just where the black wrought-iron gate ends on the left, about a 200 yard (somewhat hazardous) scramble above the road. Whether this oldster is a remnant of an older, greater population, or a freak outlier is unknown. But it’s at least one Ponderosa that wasn’t planted by man and has lived a long life in the Wasatch.

But more to the point, there is a reasonably common Pine in the Wasatch: Limber Pine, Pinus flexilis.

Background on Limber Pine

Limber Pine is a 5-needled, small-to-middle-sized pine found at altitude across the Western US and Canada. Limber Pine is a soft pine, and so is more closely related to pines like Pinons or Eastern White Pine than to Ponderosa or Coulter or Torrey Pine.

It’s not at all unusual in the Wasatch, but I’ve never seen it below 8,500 feet here, and it seems largely restricted to rocky, exposed ridgelines and outcrops- sort of like Curlleaf Mountain Mahogany (CMM) down in the foothills. And so on most decently-forested Wasatch trails in the 7,000-9,000 feet elevation band, you don’t see it all that often. Here are 2 great places to see Limber Pine:

In Summer: The Wasatch Crest trail, dividing Mill Creek and Big Cottonwood Canyons. There are several on the South-facing slope where the trail crests “Puke Hill” heading West (pic left, foreground), and then a good stand several miles further West, about a quarter-mile after the Mill D North trail drops off into Big Cottonwood Canyon.

In Winter: Easiest place is from the ski lifts at Brighton. There are plenty under the Millicent lift, and 2 big ones at the top of Majestic lift. They stand out clearly from the neighboring Engelmann Spruce by their relatively bushy silhouette.

But the coolest thing about Limber Pine is that it is a Bird Pine. Pines have seed in all different sizes; many are small and distributed by wind. (Think of these as the Cottonwood seeds of the Pine universe.) Many of these wind-blown seeds have actual wings attached to them (so these would be the samaras of the Pine universe.) Many others are large, and require a dispersal agent (analogous to acorns in the Angiosperm universe.) The most common dispersal agent for pine seeds are birds (specifically Corvids) and so these large-nutted Pines are known as Bird Pines.

The best best-known Bird Pines are Pinon Pines, of which there are 2 species here in Utah: Singleleaf Pinon in the West and Colorado Pinon, Pinus edulis, in the East. But there are other Bird Pines at higher altitude, including Whitebark (which doesn’t occur in Utah, but is common in nearby Wyoming and Nevada) and Limber Pine.

What’s really cool about Bird Pines is that they didn’t evolve independently, but rather co-evolved in tandem with Corvids, or more specifically, that subset of Corvids known as Pine Birds. Just as Bird Pines have significant adaptations to facilitate collection and dispersal of nuts by Pine Birds, such as producing large volumes of nutritious nuts, Pine Birds show numerous adaptations to collecting and eating pine nuts, such as strong beaks firmly anchored to the skull, expandable esophagi for carrying nuts, enhanced load-bearing flight capacity, hairless nostrils (to avoid clogging with pitch), and excellent memories (for later retrieval of cached nuts.)

But what’s really, really, really cool in the case of Limber Pine is that the intermediate evolutionary stages of its transition to a Bird Pine appear to still be in existence and thriving, and the showcase is the extended Mexican White Pine-Southwestern White Pine-Limber Pine complex.

The absolutely best book about the Co-evolution of Pine Birds and Bird Pines is Ron Lanner’s “Made For Each Other: A Symbiosis of Birds and Pines.”

Ron Lanner is one of my absolutely favorite tree authors. He’s written a number of wonderful guides to trees across the Great Basin and California. He’s a retired Utah State Forestry professor, who’s probably best known in botany circles for his work back in the 70’s in Pinon Pines, and specifically his (then controversial) position that California’s Parry Pinyon, Pinus quadrifolia (the world’s only 4-needled pine) is in fact not a true species, but rather a hybrid between Sierra Juarez Pinon, Pinus juarezensis, and Singleleaf Pinon.

In the book, Lanner examines the relationships between the 3 pines that together comprise the: Limber Pine in the Rockies, Southwestern White Pine, Pinus strobiformis, in Arizona and New Mexico, and Mexican White Pine, Pinus ayacahuite, in Central and Northern Mexico. These 3 closely-related pines show an almost continuous South-to-North Gradient from Wind Pine to Bird Pine. Mexican White Pine has small, winged seeds, easily distributed by wind. But these seed are often times collected by Stellers Jays, who select and cache some seeds, usually the largest. Some portion of these larger seeds is not retrieved and so the seed-collecting behavior encourages the growth of larger-nutted pines over time. Toward the Northern end of its range, Mexican White Pine seeds tend to be larger, with only vestigial wings, and more often spreads by Jays. Southwestern White Pine (which intergrades with Mexican White Pine) has still larger nuts with smaller wings, and seems much more heavily dependent on an agent (Corvid) seed-dispersal strategy.

Once the complex gets up into Utah, Nevada and Colorado, it shifts to Limber Pine, a pure Bird Pine with large, wingless seeds that is completely dependent on Corvid dispersal of its seeds. This final Bird-Pine-Transition to Limber Pine was most probably fueled not so much by Jays, as by Nutcrackers, and probably by a prehistoric ancestor of Clark’s Nutcracker, Nucifraga Columbiana.

Tangent: Nucifraga, the Nutcrackers is a genus with the Corvid family (Corvidae) that is closely related to Jays and Crows. There are but 2 species in the genus: N. Columbiana in North America, and its Eurasian cousin, the Spotted Nutcracker, N. caryocatactes. Nutcrackers are hands-down, far and away the most evolutionarily advance Pine Birds, blowing away Pinyon Jays, Stellers Jays and Scrub Jays in terms of flight-load capacity, esophageal expansion capability, flight speed, flight range, and beak and nostril design. Comparing Nutcrackers with other Pine Birds in terms of Pine-nut-collecting ability is sort of like comparing humans to other primates in terms of brain capacity: it is a whole other deal.

The wonderful thing about birds and pines in Western North America is that they provide great, accessible, real-world examples of all the facets and stages of a textbook case of symbiotic evolution.

Back to the question at hand

But enough waxing about Pines; let’s get back to the question we started with: Where are the pines here in the Wasatch? The Ponderosa and Lodgepoles that should be all over the place here in the Wasatch? In all my searching I found 2 un-convincing explanations.

In Kenneth Brown’s book Four Corners, the author makes a passing reference to soil-type issues. I’ve never found the reference anywhere else. And on the web, I found the most common “explanation”- the “Monsoon Factor.” Supposedly, because the Wasatch lack regular summer July/August monsoonal rains experienced by such pine-friendly locales as the Colorado Front Range or Arizona’s Mogollon Rim or Kaibab Plateau, pines don’t have enough moisture to survive here.

I was skeptical there as well; I’ve seen plenty o’ Ponderosa in some plenty-dry places- even summer-scorching Little Creek Mountain. So I called Professor Chuck.

Professor Chuck, a patient and kind mentor, who had last year clued me in to the lone old-growth Ponderosa in Big Cottonwood, didn’t have an answer. He’s familiar with the “Monsoon Factor” hypothesis, but unconvinced. So he suggested I ask… Ron Lanner.

Ron Lanner maintains a website highlighting his (excellent) books where I found an email address, and sent an email introducing myself and passing on my question. Professor Lanner responded the same day, and happily admitted he didn’t have any idea. He’s obviously thought about the problem for decades, and in fact he’s tracked down and investigated numerous stands of Ponderosa and Lodgepole in the Northern Wasatch and Stansbury Mountains, only to eventually discover that all had been planted.

So if Ron Lanner can’t give me an answer, I guess this one will remain a mystery. But he was kind enough to share one insight: planted Pines grow and thrive in several Wasatch locations. So the question isn’t why don’t Pines live in the Wasatch, but rather why don’t they reproduce in the Wasatch?

There’s sort of a happy coda to this story. My contact with Ron Lanner is the 3^rd time I’ve “cold-called” a noted botanist. Without exception, all three have responded to my inquiries (and follow-ups) quickly, courteously and helpfully. When I first met Professor Chuck (the 2^nd botanist I cold-called), we made a brief expedition to identify a rare oak hybrid I’d found up near Park City. On the way back to Salt Lake, he mentioned that he received invitations such as mine frequently, and that 99% were dead-ends. I asked him if he minded all the time and effort pursuing such dead-ends entailed. He replied, “No, I never mind. I like being outside, and I generally find that people who are interested in plants tend to be nice people.” And that has absolutely been the case. One of the best things about plants is the people who love them.