9 Populus (Poplar Genus)

What’s in a name? A lot! Their cultural and historical meanings can vary so much and be described so differently across diverse cultures. While European settlers were roasting and grinding Kentucky coffeetree seeds to remind them of home as they moved west, indigenous Americans had less need for a poor approximation of that beverage. Although the Meskwaki Nation are noted to consume the seeds this way, most Native peoples’ traditions involve using them differently. The pulverized root bark held widespread use as medicine for constipation, and the seeds were universally enjoyed as counters in games. Logically, it follows that the name indigenous people use for this tree is not the same as what white settlers began calling it long ago.

Sometimes, on the other hand, names coalesce across cultures. American basswood’s name comes from the word ‘bast’, referring to the fibrous inner bark which Native Americans used extensively to make cord and rope and were doing so when early settlers arrived on the scene. In Ojibwe language, ‘bast’ is called wiigob, the same name for the basswood tree itself. The processed bast fiber is called asigobaan, indicative of the extensive use of and therefore the need to name this product. Some colonists were well aware of and had used the inner bark for the same purpose historically back in their native homelands. Many newcomers dubbed this New World tree for its important use as bast, which morphed into the name, basswood. Others, recognizing the strong similarity of basswood (Tilia americana) to their own European native Tilia sp. called this New World tree American linden. In German, ‘linden’ translates as linde, in Norwegian and Swedish, lind.

The genus Populus refers to aspens, poplars and cottonwoods, all classified in the Willow family. Aspens began to be colloquially referred to (regardless of species) in some regions of the US as ‘popple’, including here in Minnesota. Most likely, this is because the German word for ‘poplar’ is pappel, and in Swedish, poppel, reflecting the ethnicity of Minnesota’s early white settlers. In the 1700s, colonists brought along with them their favorite trees, including introducing a tree to N. America called white poplar (Populus alba), mostly because it is so attractive with the leaf’s white-toned, furry underside standing out prettily in contrast to the dark green leaf top. Over time, however, white poplar has become considered an invasive species in many regions and threatens to overtake native landscapes with its root suckering habit of spreading. Like the leaves of our native quaking aspen and big tooth aspen, white poplar leaves rustle continually at the slightest whiff of breeze.

About 40 species of Populus grow around the world. Trees in this genus share one very striking characteristic. Their leaf stalks, or petioles, are flattened which causes their leaves to tremble and flutter. This is how the Swedish botanist, Carl Linnaeus, came up with their genus name. In Latin, populus means people, and to Linnaeus the rustling leaves sounded like a crowd of murmuring voices. This, I can attest to with confidence, works for any culture! What all these voices are saying and in what languages offers up an interesting compilation of stories that describe a time, a place, and a people.

Susan Jane and I are making our way back to the pavilion parking lot now, having finished with the Kentucky coffeetree area. Our plan is to cover ground along the lakeshore area and then head to the trees around the historic streetcar station (which is also the district office). That is my hope, anyway, and very possible to accomplish. Before today, I already spent some recon time scoping out and locating. The two of us are quiet for a moment, walking companionably. As we round the pedestrian path curve into the sunlight of the open parking lot, the green/white leaves of white poplar catch my attention waving from their magnificent trees, and beautifully reminding me that they are next in our work today.

Going through my dad’s books shortly after he died, my eye fell upon a small tree ID book to which my hands immediately reached. Flipping through it, I found a leaf pressed between the pages where the book easily opened. The leaf was one leaflet from an Ohio buckeye tree (on the buckeye page, of course!). Surprised, I soaked in the sight, pleased to have found an artifact my dad had placed here with his own intent, and it reminded me of his interest long ago in our yard’s buckeye that I had identified. Perhaps it was even from that tree! My heart warmed to this thought. Towards the back of the book, a small, white piece of paper appeared on which he had written a short list of tree names.

It reads:

 

Starting at Pavilion

White Poplar

Black Willow

American Elm

Crabapple, ornamental

Green Ash

River Birch

 

When it came time to bump up the map of tagged trees, this list struck me as essential to include. To me, this row of trees along the lakeshore represents species he felt were important enough to take note of. In addition, I surmised that other people on the walking path were like me, who, many years even before my naturalist proclivities kicked in, wanted to know the name that goes with the attractive leaves of what I now know to be the white poplar. Green ash is the only tree on the list that is gone now, destroyed by the emerald ash borer invasion. We have no tag for green ash trees because the city foresters have removed all those trees from the park. Locating the rest of the trees on the list, however, was important to me. It connected me to some part of my dad’s thought process, besides giving me specific species he’d already identified in the area I could use to educate myself. From the list, I learned to identify white poplar, black willow, and river birch and the general areas in the park where they grow.

Of all the trees on the list, black willow was proving to be the most difficult to find, requiring me to study up on willows. In the process, the easiest fact I learned was that willows are classified in the Willow family. Thank you very much! I also learned that willows make up a very large genus (Salix) of over 400 species of trees and shrubs worldwide, with no less than 100 species in North America. Wow! This in comparison to the mere 40 comprising the Populus genus worldwide, with only 8 of those species native to North America. So, things get a bit more complicated from here. It’s just the way willows are. While they are a stable tree species, their nature is to easily hybridize and naturalize into the landscape. Like other favorite trees, willows were also introduced from Europe, and at least 3 of these are now naturalized in Minnesota. One European variety brought by homesteaders moving west, the whitecrack willow, was already hybridized in Europe before arriving here where it tends to crowd out native species. Despite all this, willows in general seem very well adapted. The natural variability of willows is how they got along to where they are now in willow evolution. Their story.

When I was 12, my dad gave me a book by Kenneth Grahame, the classic children’s book Wind in the Willows. I absolutely loved that book (and still do), letting the full color illustrations inspire my imagination and draw me into its world. My favorite line from one of the color illustration plates always comes to mind when I think of that book. In that scene, Mole is so excited to be out on the river for the first time (having never even seen a river before) with his new friend, Rat, who has invited him on a picnic excursion in his boat.

“Please! Ratty, I want to row!”

Grahame’s story takes place in Great Britain, and the trees he’s referring to are probably weeping willows (Salix babylonica) growing on the banks of a fictional river, probably inspired by the River Thames in southern England where Kenneth Grahame spent much of his childhood. Like him, I was lucky enough to grew up nearby a weeping willow in the neighborhood. I love them! As children we used to swing from the drooping branches like Tarzan. The brittle branches often broke, but we didn’t care. I wouldn’t trade those memories for anything!

“Starting at Pavilion”, white poplar had been easy to locate. Black willow (Salix nigra), second on the list, prefers moist soils, which makes sense why it is on my dad’s list for this pedestrian path area along the lakeshore. Many willows have a very pale underside to their leaves in contrast with deeper green leaf tops, but black willow on the other hand presents both sides of its leaves as pretty much the same shade of dark green — one very good way to ID them. A huge willow grows right next to the pavilion, but the leaves have yellow-green undersides so that’s not it. After bushwhacking here and there along the somewhat overgrown lakeshore to get up close to the willow trees there, I gave up. While I did not find the black willow that day I was scouting for them, I did make the connection to the sucker sprouts my dad and I planted lakeside to the family cabin in northern Minnesota when I was a teenager. Out of the several suckers we planted those many decades ago, at least one survived. That one is a black willow. Beavers chewed halfway through the trunk many years ago, then stopped, leaving a scar from their activities, but the willow tree survived. Today it has grown into a 14″ diameter beauty.

As Susan Jane approach the two white poplars growing by the lake, I show her which one I think will work best based on my recent survey. Between us and the two trees, a few feet of underbrush and grasses bush out, but a small path leads to each. One of these white poplars is more visible from the path than the other. We think a tag on that one will entice people in and together we settle on a suitably flat spot. As usual, I proceed to pound in the nails. Then, I explain how I’ve spent some time on previous visits searching for the black willow and have not been successful, at least not yet.

“We’re running short on time,” I continue, “let’s leave black willow for later and continue towards the streetcar station trees.”

“Sure, that sounds good. Do you think you’ll even find the black willow?” Susan Jane asks.

“I definitely will,” I reply. “I’ll return later or tomorrow and keep searching until I find it.”

She doesn’t know about the backstory of the list or my determination on finding all the trees on it. I plan to locate the black willow later this week and wire the ID sign onto what I’m pretty confidant will be a clump of smallish trunks. Black willow is not an especially large tree, though it can attain 20″ in diameter. Based on the false starts I’ve had so far attempting to find it, I know it will take more bushwhacking through the underbrush. I also know that in my gear and hiking boots I contrast starkly with the dress and demeanor of the urban walkers streaming past me up on the paved path. Based on my experience of the other day, I will again studiously ignore them, just as I know they are studiously ignoring me in return. It’s the urban way to get along after all!

So, having decided black willow can wait, we continue strolling onward past the maple trees tagged from yesterday, enjoying along the way the verdant green and deep shade cascading from deciduous trees and evergreens alike.

With the many and varied common names in use for trees, Latin nomenclature plays an important role in making sure two people are talking about the same species. Linnaeus’s classification system is important, also, as an international language for sharing information, as common names in different languages can be both incomprehensible and unpronounceable. Using the Genus/species name provides specific, familiar identifiers with which to successfully communicate. Latin nomenclature provides a key to the map leading out of the labyrinths and rabbit holes into which common names can lead us.

Blue beech and ironwood are perfect examples of this.

Blue beech (Carpinus caroliniana) is a sensual tree with sinewy branches, long limbs and smooth, thin bark. For this reason it is also called musclewood. Blue beech is also known as American hornbeam due to the extreme hardness of its wood, with its fine grain polishing up to resemble horn. Beam means tree in Old English. To tangle things further, it is also sometimes called ironwood (the tree we met in the previous chapter) again, because of its very hard wood. Ironwood (Ostrya virginiana), on the other hand, is also known as American hop hornbeam. The additional ‘hop’ is due to the fact that its nutlets resemble those of hops, and the ‘hornbeam’ because, again, it is also a very hard wood. If this isn’t confusing enough, I should mention that blue beech is NOT in the Beech family at all! At this point, it may come as a relief to know that both blue beech and ironwood, while not in the same genus, are at least classified into the same family, the Birch tree family of Betulaceae. This is because of their catkins, leaves, and the fact that both male and female flowers occur on the same tree, like all birches. Better yet, a very easy way exists for telling the difference between the two species. Simply observe the smooth, sensual bark of the blue beech as opposed to the textured, vertically rectangular plates of the ironwood. Again, these two trees, with all their common name similarities and their Betulaceae family classification, still belong to separate genera.

Arriving at the streetcar station, Susan Jane and I head straight for the blue beech. I greet the tree by saying,

“Hi there, blue beech! Ready for your sign?”

It smiles back at us flexing its smooth muscles in the midday sunshine.

“Susan Jane,” I say directly, “I can’t mar this beautiful, smooth bark by putting a sign on it right in front.”

“Yes, I agree,” she replies calmly, “we should put it on the side or back.”

“Let’s do the swamp white oak first,” I suggest, needing a little time before pounding nails in this tree. Swamp white oak is only about 15 feet away and is easily dispatched, forcing us to retrace our steps back to the blue beech again. The extra time, however, seems to have solidified things in my mind. We walk around the blue beech tree once more, but we both already know the sign should face the nearby swamp white oak sign we’ve just attached.

“They can talk to each other!” we both say almost at the same time, then laugh together at our silliness.

This is the point at which the nails bend as the extremely hard wood of the blue beech resists my efforts, but it accepts the situation in the end.

Our tagged eastern red cedar (Juniperus virginiana) grows in the same area as the blue beech and is much more visible alongside the street and walking trail. An abundant grove thrives here, and the chosen tree shines from all directions. That is why I chose her, because she’s in the prime of life, adorned with an array of gorgeous, blue ripening cones. I refer to her as ‘she’ because eastern red cedar is an example of a plant species whose male and female flowers appear on separate trees. The male trees produce pollen cones that appear much different from the female’s. The fruit of the female juniper resemble tiny blue berries, but they are actually the tree’s female cones, not berries. Small mammals thrive on her fruit along with several bird species who also use the thick foliage for nesting and roosting. Edibility of eastern red cedar fruit for humans goes back hundreds of generations, used by the Lakota to flavor meats such as stewing with venison, and are also used in the process of distilling gin – again, as a flavoring. Harvest the berry-like cones when they’re blue and fully mature, from late fall into winter or even spring and you’ll have an interesting culinary seasoning to add to your spice rack. A tea made of the leaves provides a flavorful beverage high in vitamin C.

Eastern red cedar (Juniperus virginiana) also offers another example of common names confusing things. Just like our friend, northern white cedar (Thuja occidentalis) that we met in Chapter 5, eastern red cedar is not a true cedar either. The genus name reveals that this tree is actually a juniper. I suspect the reason Juniperus continues to be most commonly referred to as a cedar is because of its cedar-like aroma. I still have an eastern red cedar log my dad gave me that he found years ago in the park. The tree had fallen, and he’d cut a few logs to take home with him to burn in the fireplace for their pleasant cedar-like fragrance.

“Maybe you could cut these into coasters,” he said those many years ago, handing me a rough log, “or use as aromatic pieces to put in a drawer. Take it home and see what you can do with it.”

“Thanks, Dad.”

Here I am, decades later, “doing something with it”. Besides sawing off a few slices for myself over the years, I’m now learning so much for myself while also educating others about all these scientific names and their meanings. I didn’t know it at the time, but my science professor/teacher dad had already begun sharing his legacy with me.