Berry-Go-Round #12 Is Up!

Berry-Go-Round #12 is up over at my favorite blog, Foothill Fancies. This month’s Berry-Go-Round features a number of great plant-related posts on everything from evolution in Mexican dry forests to cycads in the Caribbean. Go check it out!

And speaking of Berry-Go-Round, guess where the next edition- BGR #13- is being hosted? That’s right kids, right here on Watching the World Wake Up, right around January 28! I somehow managed to convince the moderator that this is actually a respectable tree-blog, and a suitable location for this excellent blog carnival (I must be a great salesguy!)

For you plant-bloggers out there, if you have a recent or upcoming post you’d like included in the next BGR, I’d love to hear from you. If you’re a long-time plant-blogger, participation is an excellent venue through which to let old and new readers alike know what you’ve been up to. If you’re a new plant-blogger, it’s a great way to introduce new readers to your blog. Email submissions to me at adventurebotanist@yahoo.com (preferred), or you can use the BGR submission form.

All plant-related submissions are welcome, but some ideas that might be of interest to readers in Winter climes (like here in Utah, where we are currently freezing our butts off) might include plant survival in Winter, desert plants, or any posts about plants in the tropics or (even better) the Southern Hemisphere.

For my regular readers, I know many of you have never heard of Berry-Go-Round before, so I’ve put together this brief FAQ:

Berry-Go-Round FAQ

Q: What’s Berry-Go-Round?

A: BGR is a blog carnival devoted to highlighting recent posts about plant life.

Q: What’s a Blog Carnival?

A: A Blog Carnival is a recurring showcase/grouping of a number of different posts related to a common theme or topic. There are carnivals about all kinds of things- birds, geology, music, astronomy, business, writing- there’s even a carnival about kidney stones! Every month the carnival is hosted by a different blog, and that blogger links to a number of participating blogs. So it’s like a dozen or so posts in one.

Q: Why should I care?

A: Two reasons: First, you’ll get a nice, convenient pointer to a whole bunch of interesting plant-related posts. Second, you’ll learn about a number of blogs you’ve probably never heard of before, some of which might be interesting enough that you want to become a regular reader of them.

Q: What if I don’t care about plants?

A: Hello? Have you been reading this blog? Don’t you get by now how totally, completely, way cool plants are?? Seriously, if you’re not dialed into plants, or at least trees, you should be. All around you are these wonderful, green, growing, changing creatures that make the world so much more interesting and beautiful, each with its own hidden story to tell. As I’ve said before, the world is ruled by plants; we’re just along for the ride.

Q: So what, if anything, between now and January 28, does this mean to me as a reader of your blog?

A: It means this: January is Grown-Up Month at Watching the World Wake Up. All month long, I’m going to do my darndest to run this blog like a grown-up blog, with more cool science stuff, and less irresponsible goings-on about reclining airline seats, Sunday School, old neighbors and hotel sex.

Q: But that’s the only reason I read your blog- for the rants about airline seats, neighbors, Greek school and hotel sex. Not to mention the recurring references to your various injuries, bike racing, backcountry adventures, your lame graphics, and your poking fun at that chemistry guy for never reading your blog.

A: I said less irresponsible goings-on, not none. I’ve put a lot of work into this project to get to a point where I could do something like this. Just hang with me with me for a month, while we polish up things a bit, and then we can get back to “normal.” (Was this blog ever normal?)

Bird Feeder Week Part 1: The Big Picture

I’ve never been a big fan of sitting around the house, but if you are stuck around the house for a day in winter, one of the more interesting things to do is watch the bird feeder.

This will be the first of 4 posts (unless I flake out, change my mind or become distracted) related to the birds at my feeder. This first post will be a “Big Picture” post, talking about the significance of birds overall, and the ancestral relationships between the birds at my feeder. The 2^nd post will look at birds in Winter, and the 3^rd and 4^th posts will zoom in on one species in particular. That’s the plan, anyway.

The Big Picture

Over the past year I’ve done a few bird-related posts; in particular I blogged about 3 birds with a common theme. The birds- Steller’s Jay, Lazuli Bunting and Black-Headed Grosbeak (crappy photo from back in June, right)- are all in the midst of being “reacquainted” with an Eastern cousin- Blue Jay, Indigo Bunting and Rose-Breasted Grosbeak respectively- as a result as a result of human-created “woodland islands” across the Great Plains.

But in general I’ve shied away from birds, in part because I’ve been so occupied with plants, but also because there are so many great bird blogs out there. But though there are many wonderful bird blogs looking at species and ranges and behaviors, there don’t seem to be a lot of Big Picture blogs of birds, and the Big Picture is what I want to look at today.

So let’s start with a question: what’s the single most interesting thing about birds? Flight? Song? Navigation? Pentachromatic Color Vision? No, no, no and no. The most interesting thing about birds is how incredibly different the last 150 million years or so of animal evolution have been from plant evolution. Lemme ‘splain.

150 million years ago (Jurassic period), the plant world was dominated by conifers. There were something like 20,000 different species of conifer, occupying every ecological niche from forest giant to small shrub, across all 7 continents. Conifers had attained their ascendancy by out-competing earlier dominant plant orders, such as Lycophytes and Cycads.

The animal world at the same time was dominated by reptiles, who had out-competed the earlier dominant land animal order, amphibians. Though mammals, and proto-sorta-birds also existed 150 million years ago, reptiles were clearly dominant, occupying every ecological niche from grazing herbivore to flying scavenger.

Over the last 150 million years, the most remarkable thing to occur in the plant world has clearly been the evolution and ascendancy of angiosperms (flowering plants.) Angiosperms have thoroughly and fabulously conquered the world, out-evolving, out-adapting and out-competing conifers in all but the harshest environments, and outright banishing them from large areas of the world (such as the Amazon and Congo basins.) Though conifers are still an important group (“division”, technically), they’ve declined to a shadow of their former diversity, with a mere 630 species worldwide, compared to an estimated 300,000 species of angiosperm.

Tangent: Angiosperms are almost certainly all descended from a common ancestor, the reason being that the hallmark of angiosperm reproduction- double fertilization- is so utterly quirky and weird that it seems almost inconceivable that it evolved multiple times. For a (sort of) simple description of how double-fertilization works, see this post.

But imagine if things had gone differently. Imagine if, instead of just angiosperms ascending, there had been another, totally different plant order to evolve out of Gymnosperms around the same time, and that this other, different order- let’s call them “Othersperms”- had evolved and adapted and radiated just as successfully and spectacularly as angiosperms, and that the forests, savannahs and grasslands of the world today were constructed roughly equally of both angiosperms and othersperms.

It sounds farfetched, fantastic, and maybe a bit silly, but it’s worth thinking about, because this is exactly what happened in the animal world.

Over the last 150 million years- and more specifically over a mere million or so years 65 million years ago- the most spectacular thing to happen in the animal world has been the evolution and ascendancy of mammals and birds. Each evolved independently from reptiles, and each has been wildly successful (though from a pure species count, the birds win hands-down.) Today the animal- more specifically land-vertebrate- world is thoroughly dominated by birds and mammals, both of them, and amazingly, neither seems to be likely pushing aside the other anytime soon.

Now at this point a reader may be saying, “Wait a minute- birds and mammals don’t compete, they occupy totally different ecological niches. Mammals run around on the ground, and birds fly.” But this church-state like separation breaks now pretty quickly when you look at each group a little more closely.

Here’s a cool factoid: Of all the known mammal species in the world, about ¼ are bats. That’s right, bats. Bats that eat bugs or fruit or drink blood, and live on every continent except Antarctica. And why are bats nocturnal? Because when they fly during the day they get attacked/preyed upon by birds. If birds had never evolved, bats would have long since radiated into countless day-time species, and today we might well be watching colored bats at the feeder, raptor-bats hunting rabbits, and feeding semi-aquatic “duck-bats” at the pond at Sugarhouse Park.

And you can easily do a similar thought exercise for birds. And not just a thought-exercise, because the experiment’s already been done for us on numerous islands, New Zealand and Madagascar being the 2 best examples. When birds colonized these mini-continents in the absence of mammals, they quickly radiated out into all sorts of flightless bird niches, from grazing herbivore to aggressive, top-of-the-food-chain carnivore.

Tangent: The Bird-as-top-of-the-food-chain carnivore has even happened here in North America- at least twice in fact. The first time was ~50 million years ago, when various Diatrymas (genus = Gastornis) (pic right) up to 6’ tall stalked prey here. The second, much more recent version (15,000 to ~4(?) million) years ago) was Titanis walleri, which at over 8’ in height, had to be pretty much the Scariest Bird Ever.

Nested Tangent#1: T. walleri (melodramatic, rather overwrought artist conception/ dramatization left) appears to have been an import from South America, possibly via the Great American Interchange (GAI). For a quick GAI overview, see this post.

Nested Tangent #2: The otherwise abysmal- and phenomenally historically inaccurate- movie 10,000 BC had a pretty exciting scene of Titanis-like creatures hunting early humans.

So, the deal with birds and mammals is this: either group could totally do all the things the other group does. But somehow they’ve evolved alongside each other, and today we vertebrates live in a weird, bifurcated world, a strange, apparently enduring balance between birds and mammals.

Back to My Feeder

The Winter visitors to the feeder are a much smaller group than the hordes we see in summer. Probably 99 out of 100 birds I see out there in Winter are one of these 6 species: House Finch, American Goldfinch, Black-Capped Chickadee, Dark-Eyed Junco, Scrub Jay and Northern Flicker. All except the Flicker are Passeriformes, the class of birds to which more than half of all bird species belong, and arguably the most successful group of land vertebrates ever to exist. (By comparison, there are more than twice as many species of Passeriforme than there are Rodentia, the most numerous class of mammals.)

Within the “Backyard Passeriformes”, the House Finch and Goldfinch are the closest cousins, belonging to the family Fringilidae. The Black-Capped Chickadee and Dark-Eyed Junco represent two more families- Paridae and Emberizidae respectively, and the Scrub Jay is a member of the Corvidae family, which we’ve already met numerous times when looking at Stellers Jay and Clark’s Nutcracker.

Passeriformes arose around 60 million years ago- apparently down on my favorite prehistoric supercontinent, Gondwanaland- and are believed to be monophyletic (evolved from a common ancestor. For an explanation of monophyly, see this post.) It’s thought that the common ancestor was small woodland bird, stubby-tailed and drab-colored, but quite likely with some visible difference between the sexes, or sexual dimorphism. Sounds a lot like a House Finch (pic right).

Next Up: What’s the Deal with Migration Anyway, and Why Are These Birds Still Here?

Catch-Up, Adding to Blogroll

This is a general catch-up post, with no great science, surprise endings, or clever tangents.

On The Home Front

We had a nice holiday break. No travel, or extended family stuff, just a nice few days off together. The break included skiing with the Trifecta, a nice Christmas dinner feast with friends, and a day out backcountry skiing with Organic Chemistry Rick (guy who never reads my blog).

Tangent: Speaking of backcountry skiing, check out this article in the Salt Lake Tribune. The hero of this story- let’s call him “Tom Diegel”- is a long-time friend with whom I’ve mtn biked, and occasionally skied, for many years. (He’s also the brother of Rainbow-Spirit-Paul.) He’s a great guy- strong, smart, reliable and competent. Exactly the kind of guy you’d want with you if you got into trouble in the backcountry, and it’s no surprise to any of us who know him how smoothly he handled the situation. Way to go, Tom.

So here’s the best Trifecta Christmas story. Years ago, when Bird Whisperer (pic left, this past summer in Tahoe) was just learning how to talk, Awesome Wife and I had one of our few parenting disagreements. AW wanted to tell him the whole “Santa” story. I disagreed. My reasoning was that if we told him this whole phony-baloney story early on, then when he eventually found out the truth, he’d be forever skeptical of other “parental truths” and ignore us when we told him not to smoke pot or drink & drive or vote Republican.

Of course, AW (pic right) prevailed, and we duly propagated the Santa-Myth to yet another gullible generation. When Bird Whisperer received his “Santa” gift, a Nintendo DS (see video here) he was thrilled. The next day AW overheard him talking to his Uncle- let’s call him “Phil”- on the phone, and he said, “Yeah Uncle Phil, I believe in Santa, because there’s no way my Mom would ever buy me a DS.” As I told AW, this is our payback for telling fibs.

Bonus Video: Here’s Bird Whisperer skiing with his friend Arden. I should point out that this isn’t like anywhere near the best skiing the kid can do; he’s already a little bump-fiend. It’s simply the best filming his dad can do while skiing one-handed with a video-camera.

The long weekend also included the wedding of my good friend Clean Colin to a wonderful woman we’ve all known and loved for a long time, and who comes from the Smartest Family Ever. Seriously, this bride, her sister, her mother, her father, her brother-in-law and now her husband, are all Phd/scientist/ brainiacs who do things like work with particle accelerators on a daily basis. If Clean Colin and his new bride ever have a baby, I fully expect the kid to have telekinetic powers and conquer the planet.

The wedding was also notable in that it’s the first time I ever saw my core mountain-biking buddies in suits, which I am including a photo of here (above, left), for no other reason than I told them I would.

Adding to Blogroll

I’ve added 3 new blogs to the blogroll.

First is Catalogue of Organisms, a fascinating biology blog written by an Australian doing his Phd in Arachnid Systematics. His posts cover an amazing range of topics, from nematodes to angiosperms, and each posts actually includes references, like a mini-scientific-journal-paper. Seriously, this guy is so smart I swear he must be related to Colin’s wife. Check out his recent post on Strep for some seasonal reading.

Second is Myrmecos, by U. Illinois biologist and photographer Alex Wild. Know how I’m always going on about how I want to do a Bug Blog? This guy’s already got it, and his posts feature (his own) fabulous photos.

Third, on the biking side of things, is KanyonKris, whom I’ve never met but consider a kindred spirit. KanyonKris is another Utah mountain biker with similarly aged kids and some of the same interests (particularly astronomy) as me. He lives down in Utah Valley (Note for non-Utah readers: Utah Valley is the valley immediately South of Salt Lake Valley. Similar landscape, but more dramatic) and so his ride write-ups tend to feature a similar but different set of trails than mine. Kris has been a frequent, constructive and welcome commenter on this blog, and his blog often features practical reviews and advice from everything from economical night-riding lighting systems to Sonic Hiker Warning Devices (bells.)

OK, all caught up. Back to serious blogging.

Skiing Through Aspen, And All About Photosynthetic Bark

This past weekend was my first real backcountry ski day of the season, by which I mean not just going to a resort or skinning up Porter Fork or Mill Creek, but a real backcountry ski day, where you pack beacon & shovel, skin up a couple thousand feet and yo-yo ski several runs, while trying not to get killed in an avalanche.

Ski Tangent: I do 3 types of skiing: resort (mainly with family), XC (mainly in the Uintas) and backcountry. My backcountry setup includes nice wide skis (Volkl Snowrangers) and heavy plastic boots (Garmont Liberos). I use skins with these skis to ascend slopes, and I spend most of my time on telemark skis between 7,500 and 9,500 feet, ascending into a suitable area- usually somewhere up Big Cottonwood Canyon- where I can yo-yo ski several runs. The initial descent usually entails the grueling job of breaking a “skin-track” up; successive ascents on the same track take only maybe ½ the effort. I usually do this with friends, but sometimes solo as well. Despite being on telemark skis, nearly all of my turns are alpine turns, but I like the low-weight and flexible boots of telemark gear, both for climbing as well as picking/stepping my way out of brushy or problematic areas.

This type of skiing is by far the most dangerous of the 3. It requires safety gear (beacon, shovel, probe), knowledge of snow conditions, caution and good sense. Different backcountry skiers take different approaches to avalanche safety. Some are virtual “snow scientists”; run into them on the skin-track and they’ll talk you into a daze with details of crystal formation and snow compaction. Other skiers focus more on safety gear (i.e. Avalung) while still others focus primarily on slope, terrain and anchor points. I use a 4^th strategy that encompasses elements of all of these and other techniques and which I refer to as Being A Total Pussy. That’s right, I am a total pussy in the backcountry. None of us knows how we’ll go, but I am determined not to spend my final minutes suffocating under snow. I stick to shallow-angle slopes, in the trees, under all but the most benign conditions.

Organic-Chemistry-Rick (guy who never reads my blog), our friend Jane, and I skinned up into the Beartrap drainage on the North side of big Cottonwood Canyon (map above, right), and despite the abysmal weather (super-cold, high winds) and fairly meager early-season snow cover, found some great snow and had a good day.

Science Fiction Tangent: I have a weak spot for end-of-the-world, Armageddon-type movies. The weekend before last, when Awesome Wife was away, I watched “I Am Legend”, which is set in the ruins of a post-plague New York City. The movie’s real eerie, because the protagonist is driving and exploring all around this abandoned, overgrown city, which of of course used to be all busy and bustling with activity.

That’s the same feeling I get the first backcountry ski day of the season. It’s always the first return to the high backcountry that I last saw in Summer or Fall, and often the exact same hillsides I hiked or biked just months ago (for example on this tour we were skiing within 100 yards or so of the Wasatch Crest trail.) But where there were leaves and flowers and birds and crickets and all kinds of great smells the last time I was here, now there’s just silence, wind and bare trees. In the early winter, this “ruins” feel is exacerbated by the dead shrubs sticking out of the snowpack. Recognize this guy? (pic left) It’s the remains of a Cow Parsnip stalk, Heracleum maximum, it’s double composite flower-head architecture still clear in death.

We skied several runs through an Aspen forest. I’ve gone on previously about the beauty of Aspen forests in both Summer and Fall, but in the Winter they have yet another kind of beauty- ghostly, quiet and open, and this winter beauty has a weird, almost otherworldly quality to it. If you’ve ever read C.S. Lewis’ “The Magician’s Nephew”, Aspen forests in winter somehow remind me of the “Wood Between The Worlds”, which isn’t really part of any world, but leads to all worlds.

On a more mundane level, Aspen forests offer the best tree-skiing in the Wasatch. They’re open, nicely-spaced, with no winter-foliage to prevent snowfall from reaching the forest floor. Remember the tree-rule of backcountry skiing: break the up-track through PLTs, but ski down through Aspens.

Aspens in the Wasatch almost always reproduce clonally, and so there’s a good chance we spent the bulk of the day skiing inside a single clone. As we repeatedly re-ascended our skin-track, I had plenty of time to think about what these trees are doing in Winter.

Back in the summer when I first blogged about Aspen, I went on and on about their genetics, evolution and foliage, but I glossed over 2 of the most remarkable things about this tree. The first is that it is so ALONE. Think about it: as you hike, ski, bike, or just drive through the Wasatch, away from the creeks, there’s only 1 deciduous real tree in the mountains- Aspen. Everything else is a PLT or maybe a Mountain Mahogany or a Rocky Mountain Juniper. And what’s more, is Aspen stands alone clear across Northern/Northwestern North America. Go up to Montana, or Idaho, or down to New Mexico, or clear up to the Yukon, stay away from the streamside stuff, and know what the only deciduous tree you’ll find is? That’s right, Aspen. And there’s more! Zip across the Bering Strait and start cruising across the boreal forests of Siberia, and there’s pretty much just one deciduous, non-riparian, tree alongside the Pines and PLTs of the Russian North- Eurasian Aspen, Populus tremula.

And this alone-ness segues directly into the 2^nd remarkable thing about Aspen: its competitiveness. Aspens in the Wasatch and elsewhere are surrounded by conifers (PLTs here, PLTs + Pines elsewhere.) Every Spring, while the Aspens waste valuable weeks growing new leaves, the conifers, with their needles ready, start photosynthesizing and growing. As soon as the temps bust 50F, they’re kicking it. How do Aspens compete?

One way of course, we’ve already talked about: they spread clonally and quickly, taking advantage of disturbances such as avalanches, forest fires and clear-cuts. But it turns out that Aspen has another trick to compete with the PLTs: photosynthetic bark.

When we think of chlorophyll, we think of leaves. (See this post for some basic info on chlorophyll, and an overview of the symbiotic evolution of chloroplasts.) But more than 60 species of tree and woody shrub have been found to contain substantial amounts of chlorophyll in their bark. Of all of them, Aspen is the champion, with more chlorophyll in its bark than any other tree known. The bark-chlorophyll in Aspen is concentrated in a super-thin layer (about the thickness of a leaf) that lies within 1mm of the exterior surface of the bark. (The exterior layer is called the periderm. When you brush your hand against an Aspen trunk, that white powder that comes off is dead periderm cells.)

The photosynthetic layer comprises less than 5% of the total volume of bark on the tree, but it accounts for a whopping 17-40% of all the tree’s chlorophyll when the tree is fully leaved. The bark-chlorophyll is most heavily concentrated on the upper, South-facing trunks.

Tangent: At this point an astute reader may be thinking, “Ah-ha! That’s why I sometimes see Aspen trunks that have a greenish tinge. That must be bark-chlorophyll.” To which the answer is “Yes, but…” The greenish tinge of the bark of some Aspens does indeed indicate the presence of chlorophyll. But a greenish tinge doesn’t necessarily mean that a given tree has more chlorophyll than an Aspen with pure white bark. The whiter Aspen may just have more dead periderm cells on/in its bark.

The presence of chlorophyll in its bark appears to help Aspen in a couple of ways. First it provides a photosynthetic head-start in Springtime, before its new leaves have developed. This appears to be especially important in younger Aspen, and it negates at least some of the early-season photosynthetic advantage enjoyed by neighboring PLTs. Even during the summer, bark chlorophyll accounts for 10%-15% of all photosynthetic activity in a typical Aspen.

But the second way bark chlorophyll helps Aspen is in utilizing or “refixing” CO2 given off by the tree. Even in winter, trees continue to respire, and as they do so, lose CO2. Bark-chlorophyll is able to recapture some of this CO2 through photosynthesis, which in turn helps create a more aerobic environment inside the tree which helps defend against certain fungal infections.

Lastly, bark-chlorophyll may help Aspen- even in summer- in times of drought-induced stress. The stomata (pores) in leaves respond to drought by closing, which in turn stops any photosynthesis. But bark is able to continue exchanging gases- and thereby continue photosynthesis- through structures called lenticels, which show up as the horizontal lines on Aspen bark (though lenticels are in no way unique to Aspen.)

Tangent: Of course the type of photosynthesis we’re talking about in Aspen is the “standard”, C3 photosynthesis. But we’ve already seen that there’s at least one other photosynthetic process, C4 photosynthesis, which we talked about way back during Weed Week (man, was that a cool week or what?) when we looked at Crabgrass. And it turns out that there’s another (yes a third!) type of photosynthesis that actually functions while the stomata are closed. I’m hoping to visit a number of plants that employ this third type of photosynthesis sometime in the next 60-90 days, but in the meantime I’ll give you a quick hint: This week, UTRider is surrounded by plants that use this third type of photosynthesis.

I’ve been skiing, biking and hiking in Aspens for nearly 2 decades, and they never cease to fascinate me. When I first encountered them, it was their visual and sonic beauty that caught my attention. As I’ve gotten to know them better I’ve become awed by their elegance, engineering and sophistication. Aspens are way cool.

More Solstice Geometry And The Most Awesome Graphic Ever

Yesterday, the Winter Solstice, the sun peaked at Sun-Noon (which was 12:25PM here in Salt Lake), at only 25.8 degrees. From hereon for the next 6 months it’ll peak a little higher every day until on June 20 it’ll peak way up at 72.6 degrees. That’s a huge difference- almost 47 degrees (or twice the Earth’s declination from the solar plane.)

Tangent: It’ll start to creep up real slowly, gradually, just a teeny bit each day, then speeding up, faster and faster till the Equinox, after which it will gradually slow its rate of descent gradually till it “stops” and starts descending again at the Summer Solstice. You can think of the Sun as a bungee-jumper who right now is just starting to rebound from the bottom of his/her jump. The reasons behind this changing rate of ascent/descent are fascinating, but are the topic of a whole other solar geometry issue, that I’ll put off for a bit… most likely till the Spring Equinox.

But when I blogged about this at the start of Dark Week, an astute reader- let’s call him “Kevin”- commented on how surprising it was that the sunrise and sunset azimuth angles varied by a whopping 66 degrees (I think it’s actually a bit closer to 63) between the Winter and Summer solstices. 66 (or 63) is a lot more than 47; what the heck is going on?

Explanation of “Azimuth”: The sunrise azimuth angle is one of those terms that sounds complicated, but is really simple. It just means the angle, measured from due North, that you go around the horizon to where the sun rises. So due East is 90 degrees, and due South is 180 degrees. On December 21 in Salt Lake the sun rises at 121 degrees, so South of East, but still more East than South…

This is one of those things that doesn’t make sense unless you can visualize it, and then it makes total sense. So I dinked around for close to an hour trying to come up with a suitable graphic until I got the brilliant idea of searching online for such a graphic. And I’m happy to report that I found the Most Awesome Graphic Ever. The University of Nebraska Astronomy Dept put together this tool that models solar position relative to an observer at any date, any time and any latitude on Earth. Not only that, but it has drag & drop controls to change date, time and latitude. It even has an animation mode with adjustable speed! (Seriously, if you’re already already bored with this post and want to blow it off, that’s cool, but just check out the Nebraska site.)

The graphics I’m using here are just screen shots from the U. Nebraska site, with angles added by me.

On the Equinoxes, March 21 and September 21, the sun always rises at azimuth angle 90 and sets at azimuth angle 270, or in other words, rises exactly due East, and sets exactly due West.

But as it climbs up in the sky of the Northern hemisphere, it does so in an arc that is tilted to the South by a number of degrees equal to the latitude of the observer. So at Sun-noon on September 21 in Salt Lake City, the sun peaks at just 49 degrees in the sky, which is 90 degrees (straight up) minus 41 degrees (latitude of Salt Lake.) Easy enough.

Cool Side Note: On the Equinox, the sunrise Azimuth is 90 degrees for every point on Earth. No kidding. It makes sense if you can visualize it. If you can’t, take an ornamental ball off the Christmas tree and play with it and a lamp until you figure it out…

Now by December 21, the high-noon-sun angle has decreased by 23.5 degrees (the Earth’s axial tilt) but the sunrise azimuth has moved south by 32 degrees, and the reason for this is that from the perspective of an observer, the horizon is always a 2-dimensional circle around that observer, which makes sense, since the Earth is a sphere.

And while the arc of the sun has been moved 23.5 degrees lower in the sky in a due South direction, that equates to more than 23.5 degrees around the circle of the horizon, with the extreme example being that if the arc were lowered to where the peak sun-angle at noon were 0 degrees, the sunrise azimuth would be 180 degrees.

And in fact this is exactly what happens at latitude 66.55 degrees, the Arctic Circle. On the Winter Solstice the sun just “blips” above the horizon due South for a moment and lies out of sight the rest of the day.

On the Summer Solstice at the Arctic Circle, the sun stays above the horizon all day except when it momentarily kisses the horizon at due North. The angle difference between sunrise azimuth on December 21 and June 21 at the Arctic Circle is therefore a whopping 180 degrees.

At the Equator it’s only 47 degrees (twice the Earth’s declination.) Everywhere else in between, it’s somewhere between 47 and 180 degrees, with the swing increasing dramatically the further North you go. Here in Salt Lake the swing is about 63 degrees, with a Summer Solstice azimuth of around 58 degrees, and a Winter solstice azimuth of around 121 degrees.

There’s a formula to compute the sunrise azimuth here. It entails actual trigonometry, and therefore goes beyond the kiddie-math scope of this blog.

Trigonometry Appendix: But if you really want to know it, here it is:

where delta is the actual declination for the Earth on that specific day, and omega is something called the “hour angle”, which is computed by this formula:

where alpha is the altitude angle and fi is the observer’s latitude. OK if there’s a record for the least-read paragraph in my blog, this is gotta be it. Seriously, no one is ever going to read this trigonometry stuff. If I ever decide to confess to killing Jimmy Hoffa or a harboring a secret crush on Sarah Palin I'm gonna come back and do it right here in the middle of this paragraph.

But if you can visualize the graphics (and maybe play with the U. Nebraska tool a bit) you’ll get the idea. Anyway that’s why the sunrise/sunset position is so dramatically different between winter and summer solstices, and why that difference is greater the further North you go.

Passing the Winter Solstice always feels somehow like cresting a monster climb during a bike race (the best example being Bald Mtn Pass during the High Uintas Classic, which will be- ironically- on the Summer Solstice.) Just when it gets really unpleasant, just when you’re about to crack, when you doubt you can hang with the lead pack for even another 30 seconds, the climb levels off, you reach the pass, and there’s a whole new world on the other side. And then things get really interesting.

PLT-Spotting At Brighton

So this past weekend, while Awesome Wife and Twin B were away for their mother-daughter weekend, Bird Whisperer, Twin A and I went skiing up at Brighton. The first ski day with the kids each year is always a bit of a challenge, particularly in foul weather. There’s inevitably a “dialing-in” process of dinking around with balaclavas, mittens, boots, hand & toe warmers that ups the hassle-factor significantly, combined with necessary encouragement and prodding that quickly exhausts my fair-to-middling repertoire of parenting skills. Nonetheless, we had a good time. In a couple more weeks the kids will start lessons, which means either a) Awesome Wife and I will take them up and then ski together during their lessons, or b) Awesome Wife will stay home and I’ll take them for their lessons, during which time I’ll ski solo.

Skiing solo is OK, but sometimes after a while you can get burned out talking to strangers on the lift. A typical conversation goes like this.

Other Skier: Great day today, huh?

Me: It sure is.

Other Skier: I’m from Dallas. Where are you from?

Me: Salt Lake.

Other Skier: Oh, you live here in Utah?

Me: Yes I do.

Other Skier: So are you a Mormon?

Tangent: This “Are you a Mormon?” thing also happens frequently when I travel out-of-state, and I always get a kick out of it- especially because I often get the question while I’m drinking coffee, or even a beer. The question never ceases to amaze me. When you meet someone from New York, or Houston, or San Francisco, you don’t immediately ask them if they’re Jewish, Baptist or gay. But somehow it’s OK to ask a Utahn you just met, whose first name you don’t even know, what their religious affiliation is. I sometimes wonder exactly how “Un-Mormon” I’d have to appear to not get this question. If I wore a yarmulke, would that do it? How about if my nose were pierced? What if I were sitting naked in the desert, smoking a joint? Would I still get asked then?

Clarification: I don’t smoke pot, and I don’t sit around outside naked. But if I did do those things- especially at the same time- the desert would be a cool place to do them.

So sometimes I just prefer to tune out on the lift and avoid chit-chat. And when I do, I often find myself passing the time by identifying PLTs.

The PLT seasons for me are summer and winter. In the summer I’m up high biking and hiking all the time. In the Fall I’m driven down to the foothills by snow and mud, but when Winter finally sets in I return to the high country to ski, and I’m back in the PLTs again. Come Spring (aka Mud Season) I’ll be driven down low again until late May/early June, when the PLT cycle starts anew.

So the first ski day of the year is always a nice reaquaintance for me with Wasatch PLTs. Brighton Ski Resort, which ranges between 8,300 and 10,000 feet, is dominated by 3 PLTs: Engelmann Spruce, Subalpine Fir, and Limber Pine. (I posted about each this summer, and you can follow the links if you want background on any/all.)

Engelmann Spruce is the most common, so if you see a PLT at Brighton and have no idea what it is, chances are it’s a Engelmann Spruce. There are 3 easy ways to ID them from a distance, and 1 easy way close up. From a distance, the first way is bark (pic left); if it’s orangey-brown color, it’s an Engelmann Spruce. Second is cones. Firs don’t bear any cones in the Winter, but Spruce still do, particularly in the upper branches, which you can get a good look at from the lift.

Tangent- Cones: The biggest surprise for me Sunday was all the cones still up in the high branches. All over the place at Brighton, the Spruces are loaded with cones. What gives? Don’t they have any Red Squirrels up at Brighton? If I were a T. hudsonicus, I would get my butt up Big Cottonwood Canyon. At 2500 calories of seeds per cone, at least 200 cones per tree, and tens of thousands of cone-loaded Spruce, there’s probably enough food up there to tide 4,000 Red Squirrels through the Winter.

Kiddie-Math Appendix: Each seed = 15 calories. Each cone has 150-175 seeds. Assume a “loaded “ tree has at least 200 seed-filled cones. Assume 100,000 trees in upper Big Cottonwood Canyon (total swag). Total equals 50 billion calories. Each Red Squirrel needs 12 million calories to make it through winter, so there’s enough food for 4,166 Red Squirrels.

And third, the Spruce look “fatter” or at least “fuller” in profile than the Subalpine Fir, which are really thin. Engelmann Spruce is a climax species in these parts. It doesn’t do well as a sapling in direct sunlight, and typically grows up in the shade of more sun-tolerant pioneers, such as Limber Pine or Aspen, or even Subalpine, White or Douglas Fir. But once it attains full height, it shades out these other species and comes to dominate large stretches of PLT forest. In the absence of natural disturbances, such as fires or avalanches, this dominance is broken less often, and so since Euromerican* settlement Engelmann Spruce has come to dominate even more thoroughly in large stretches of the Rockies.

*”Euromerican”. Like that? I just made it up now. I’m going to trademark it, like I should have done with “Utard” back in the 90’s. Yes, I’m the guy who invented the word “Utard.”

The close-up way to tell Spruce-any Spruce – from (any) Fir is to pluck a needle. If you can roll it between your thumb and forefinger, it’s square in cross-section and therefore Spruce. Firs and Douglas Firs have flat needles that can’t be rolled.

The most common associate of Engelmann Spruce is Subalpine Fir. And even though Subalpine Fir isn’t anywhere near as shade-tolerant or long-lived as Engelmann Spruce, it has one good competitive trick: it grows fast. And so it often capitalizes on any disturbed open spots before Spruce can effectively react, and so persists alongside it.

There are 2 kinds of Firs in the Wasatch. Most of those you’ll see from the lifts at Brighton are Subalpine, tall, skinny and spire-like. But I’ve come across White Fir here as well, while tree-skiing down lower in some of the relatively sheltered draws served by the Snake Creek lift. It can be tough to tell the 2 Firs apart. As a rule, if it’s alongside a bunch of Spruce, it’s probably Subalpine; if it’s alongside Douglas Fir, it’s more often White Fir.

Speaking of which, I don’t recall ever skiing past a Douglas Fir at Brighton, and generally they don’t seem common much above 8,500 feet in the Wasatch.

The bark of Subalpine Fir (pic right) lacks the orangey-reddish tones of Engelmann Spruce bark, and it’s often smoother, less patchy/peeling looking. When young the bark is pretty smooth, and gets more furrowed with age.

The 3^rd PLT isn’t technically a PLT, because it isn’t just Piney-Looking, it actually is a Pine, Limber Pine. Limber Pine is of course interesting because it’s the exception to the no-pines-in-the-Wasatch rule. It’s real easy to pick out close-up because it’s the only conifer the Wasatch with needles bundled in groups of 5. It’s also easy to pick out at a distance from the lift; its profile is distinctly “bushy”, “spreading”, and clearly un-spire-like compared to the surrounding Firs and Spruces. Limber Pines do lousy in the shade and prefer open sunlight. They seem to be very effective at seeding on and around rocky, exposed outcrops and ridgelines. Here at Brighton they’re all over the place under the North-facing open slopes served by the Millicent lift, and there are also a couple of isolated ones at the top of Majestic lift (pic right.)

Limber Pines have a neat co-evolutionary history with corvids and appear to have a fascinating kinship story with Southwestern White Pine in Arizona and Mexican White Pine down in (wait for it…) Mexico. I did a post on the whole Limber Pine-Corvid/White Pine Complex deal back in August (which is a totally cool story) that you can check out here if you’re interested. This book on my Suggested Holiday Gift List last week provided much of the source material for that post and makes a great read for anyone who really wants to understand the relationships between birds and pines.

Now wasn’t that more interesting than shooting the breeze with some tourist about his vacation? Man, I am telling you, when you’re dialed into trees, there’s always something cool going on!