June, Cottonwood Seeds And Neighbors

So I have a post today- a real post, with some real botany. But first, can I just say: How cool is June? Seriously, the weather is amazing, new trails are opening up almost daily at the 7,000-8,000 foot level, and they’re wonderfully green, flowery jungles, with things leafing and blooming like crazy. And then the light! Hours and hours of light! Light when you wake up, light when you come home from work, light almost till you go to sleep. And every day there’s even more light, and it seems like the wonderful summer just stretches out endlessly ahead, and it’s almost impossible to wake up each day and not be thrilled just to be alive.

Tangent: Yes, I love June. It’s the month I look forward to the whole rest of the year. But sadly, it also reminds me that our civilization is fundamentally flawed. Because in an ideal society, one that really was in tune with the natural world, and had its values and priorities straight, we would all get the entire month of June off. Seriously, how sick, how crummy, how wrong is it to be inside a climate-controlled office* on a day like today?

*pic right= photo of my office building. It’s actually a very nice office to work in. I just wish one could open the windows.

Okay enough venting- I know you guys come here for more than just Middle-Aged-Man-Ranting, so let’s talk about something cool. No, not Antonio Banderas or German tourists or my old college girlfriends*- let’s talk about Cottonwood seeds.

*I actually didn’t have all that many girlfriends in college, so if I m going spice up the occasional post with stories involving them over the course of this project, I need to dole them out sparingly. You’ll know I’m hitting rock-bottom when I blog about the one who had a moustache.

In Monday’s post I covered-in great detail- the least pleasant moment of Saturday’s race. I neglected to mention the best moment. It was on the final climb. The final pack has broken up, and though I was rapidly dropping most of them, the leaders were getting away. I was hammering for all I could, a nascent cramp building in my left calf, and my heart rate racing at 183 BPM. But as I climbed through the narrow canyon called the “gap” and looked ahead to the leaders, the mid-day sun lit up hundreds- maybe thousands- of little bits of cotton floating on the breeze, and even in my haze of race-pain, I couldn’t help but think, “Wow- this is really beautiful.”

Several months back, when I was thinking about whether or not to continue this project for a 2nd year, I thought about things that I’d always meant to get around to blogging about last year, but didn’t. Cottonwood seeds were at the top of the list.

All About Cottonwood Seeds

You don’t have to drive up to Idaho to see cotton floating around; if you live along the Wasatch Front you just have to walk outside. My office park sits right alongside a stretch of Little Cottonwood Creek lined by a few dozen Cottonwoods, and for the last week or so the air around has been filled with their seeds.

The Cottonwoods you see around the valley are of 2 species, and they’re easy to tell apart. Fremont Cottonwood, Populus fremontii, has fairly broad leaves (pic right) that look like a larger version of Aspen leaves. Cottonwoods and Aspen are closely related (same genus) and Fremont leaves have a very Aspen-like stem architecture that is thick up & down, but narrow side-to-side. When a breeze hits Aspen leaves, this thin-side-cut design makes them sway side-to-side, which causes the distinctive rustling of Aspens in the wind- thousands of leaves sliding back and forth across the tops and bottoms of their neighbors.

Side Note: Utah has a 3^rd species of Cottonwood, Black Cottonwood, Populus trichocarpa, which occurs only in Wasatch, Utah and Washington Counties. I have yet to spot/ID it.

Fremont Cottonwood leaves do the same rustling in the wind, but because they’re larger, the pitch is lower. Think of Aspen as a violin, Cottonwood as a cello.

Fremont Cottonwoods are common down in the canyon bottoms of Southern Utah, where they provide the most welcoming shade around. (pic left = Arizona Steve laxing in Cottonwood shade, Twin Corral Box Canyon) Though they’re common up here along the Wasatch as well, I don’t think they’re native; I believe they’re all either planted or (more commonly now) escapees. Our native Cottonwood here in the Wasatch is Narrowleaf Cottonwood, Populus angustifolia, which is similar to the Fremont in structure/form, but has way different leaves: narrow, pointed and willow-like (pic below right).

Side Note: They also don’t rustle the same way. Not only are the leaves different, but the leaf-stems are different in cross-section.

When I first moved to Utah I thought Narrowleafs a poor substitute for the fuller-leafed Fremonts, but over the years they’ve grown on me. Though you typically don’t mtn bike or hike alongside them in the Wasatch, there are a few nice trails around where you can do so, including the Mormon Pioneer Trail (between Big Mountain Pass and the road connecting Jeremy Ranch to East Canyon) and several of the trails in the Diamond Fork area, including lower 2^nd Water and lower 5^th Water. The lower Diamond Fork trails in particular are neat; you’re cruising along in a shady forest, but just 20-30 feet away on either side is scrubby, open semi-desert.

Tangent: This brings up an interesting point that Wasatch trail users rarely think about- why so few good trails in riparian zones? Most public lands are administered by the Forest Service or the BLM, and generally these 2 agencies, when they were formed, lapped up all the land that hadn’t been homesteaded or otherwise claimed by settlers. Settlers when they arrived naturally chose the lands with the best water. River Valley bottoms were the best, as they offered both farming and grazing, which explains why you almost never find public lands in broad river valley bottoms in the Intermountain West. But riparian zones were also desirable to settlers. The density of lush vegetation in riparian zones makes them better grazing areas than the surrounding hillsides, and so today a high proportion of riparian zones today lie within private lands. And of course many of the riparian areas that are on public lands have been overgrazed to the point where… they’re not really riparian anymore.

Cottonwoods of all kinds are wind-pollinated, like Aspen, Maple or Oak. They flowered about 5-6 weeks ago, when I profiled a male Fremont flower. Cottonwoods are dioecious (meaning that a tree has either male or female flowers, but not both) like their cousins Aspen and Willows. When I did that post, I marveled that something as phenomenally improbable as wind-pollination could ever work, but obviously it did; every single one of those zillions of bits of cotton floating around right now is the result of a pollen grain somehow winding up on the stigma of a flower on a female catkin (of the correct species.)

When those lucky pollen grains reached their targets, pollination occurred within 24 hours*. In the weeks following the flowers developed into seeds surrounded by tufts of cotton, and in the last 2 weeks, the protective sheaths covering the developing seeds/cotton have been drying, splitting and peeling back. As they do so, the seeds/cotton are exposed to the wind, and carried away.

*If you want to know exactly what happened during those 24 hours, see this post.

The cool thing about cottonwood seeds is of course the cotton. It’s a way, way different approach to wind-dispersal than a maple or an elm, both of which essentially grow a winged seed-package (called a samara) to carry their seeds away, or even from the little parachutes of Dandelion, Salsify or Thistle seeds (which are actually dried/modified flower calyxes.)

Real cotton, like the kind we make clothes out of, comes from one of several species of shrub belonging to the genus Gossypium, which is native to both the old and new world, and has a fascinating history in that it was domesticated independently several thousand years ago in both hemispheres (in the Americas first.) Today the vast majority of commercially grown Cotton is G. hirsutum, (pic right) native to Central America and the Carribbean.

Tangent: The history of Cotton in the US is way beyond the scope of this post but is something every American should understand. Cotton farming- fueled by the late 18^th century invention of the cotton gin- drove the massive expansion of the slave trade and, indirectly, everything after it- the Civil War, Reconstruction, Jim Crow, segregation, civil rights… the plant shaped the course of American history.

Cottonwoods and Cotton are not closely related and evolved their “cotton” independently, but the basic idea/structure is the same- surround the seeds in little tufts of fibers so that they can be carried away by the wind. The fibers comprising the tufts are called trichomes, which are basically “plant-hairs”. You see trichomes all the time on lots of plants- a recent example we looked at is the hair-covered leaves of Singlestem Groundsel (pic left), and it’s interesting to think that whatever you’re wearing right now, at least part of your body is probably clothed in them.*

*Unless you read my blog naked, in which case I don’t want to hear about it.

The advantage of the cotton strategy is that it’s cheap- growing a little tuft of cotton requires fewer resources than cranking out a full-blown samara. But the disadvantage is the low flight-load capacity of a cotton-tuft, which necessitates tiny seeds. With bits of cotton all over the place, you might wonder that the valley isn’t carpeted with Cottonwoods. But the chances of any one seed becoming a tree are ultra-slim. A Cottonwood seed needs to land on damp, open soil- usually along a stream, creek or river-in direct sunlight. If it lucks out and lands in such a spot, the seed will germinate within 48 hours. But the window is short. Although Cottonwood seeds can remain viable for over a month, sometimes even 2 (which is fairly short by seed standards anyway) once they get wet, they’ve only got 2 or 3 days tops to germinate, then they’re done.

The reason for this narrow window is the tiny-ness of the seeds; they don’t have a sizeable, nutritious endosperm* to support them for weeks and weeks. They need to germinate, get growing and start getting nutrients and water from their environment fast.

*Endosperm was explained in this post. An example of a seed with a really ample endosperm is an acorn, which gives them a lot more wiggle-room to get established/growing.

During the first crucial weeks, the level of that watercourse needs to stay somewhat consistent; if it rises a couple of feet the seedling will drown, and if it dries up it’ll die. Abandoned secondary stream channels are often good sites because they typically have significant sub-surface water.

People complain about Cottonwoods for lots of reasons- some good, some bad. The “good” reasons are that they grow quickly and often destructively. Their large limbs rot, hollow out and fall off with age, and their aggressive roots crush pipes and buckle sidewalks. The “bad” reason is the seeds. People will complain about the cotton all over as if it were locusts or manure. I always find it beautiful, and though it can accumulate a bit, it’s easily swept off a walkway or steps, and it’s probably for this reason that Cottonwoods are sometimes referred to as “trash trees.”

Tangent: I hate that term. There’s no such thing as a “trash tree”, just a tree that you would prefer not be in your yard. The term is also used around here for Box Elder, another fine native undeserving of such scorn. Long before we were decorating our yards with Spruces, Firs, Silver Maples and Austrian Pines, settlers- and before them Indians- enjoyed the shade of these fine trees. For us to show up and start talking smack about them is really in poor taste.

More About My Neighbors

And this brings me to the part about neighbors. Our house, which we’ve lived in for 7 years, sits on a cul-de-sac. Cul-de-sacs are generally nice places to live for just about anyone, but they are wonderful places for families with small children to live in. They have minimal traffic and are easy to keep an eye on, making them perfect places for kids to bike, run, chase each other and throw balls around while their parents keep an eye on them, even if that parent just sits in the driveway sipping a cold one.

But over the last couple of years, the trend on our circle has been fewer families and more retirees. The retirees are fine neighbors in their own right, with perfectly-manicured yards and, few comings-and- goings and no loud music, but gradually the circle has become quieter, more staid, and less, well, fun.

Our most recent new neighbor moved in last Summer, across the street. Another (semi) retired couple, they’re self-described “Flippers” who bought the house with the intent of flipping it for a quick profit. Needles to say, their timing sucked, and they’ve been living there for about a year.

In the early months I made a few attempts at conversation, though early on I got the sense we’d never be close friends. It might’ve been when I first went over and he was gardening while listening to Limbaugh, or maybe it was his habit of ending every 4^th or 5^th sentence with the phrase, “…when Obama raises my taxes!”

But I knew for sure that we’d never be buds when he embarked on a tree-cutting jihad in his yard, referring to the beautiful old Box Elder in the back as a “trash tree.”

Next time you’re annoyed by the cotton floating around your yard, think of this: Each one of those little tufts contains a tiny speck with an entire volume of encyclopedias* inside containing detailed instructions for how to grow an entire, wonderful shady tree, that flowers and leafs out every Spring and turns beautiful gold every Fall, and will do so over and over again for 100 years or more. That will provide support, home and shade to everything from people to owls to ants to lichens to moss and fungi to your grandchildren. Every one of those tufts contains more complexity, subtlety, finesse, reliability and potential power than your bike, your car, your iPhone or whatever gizmo you’re reading this on. They are way, totally awesome. In a couple more weeks they’ll be gone, so try and take a moment and check them out.

*Of course technically this analogy holds for any one of the gazillions of cells of organic debris all around us. But it’s cooler when they’re floating through the air, lit up by the sun.

Last month my neighbor finally “flipped” his house. On Sunday we met the new neighbors. They’re a family with 3 delightful kids, 1 of them the same age as the twins, the other 2 the same ages as next-door Hunky Neighbor’s kids. This June is shaping up great.