9 Populus (Poplar Genus)

What’s in a name? A lot! Their cultural and historical meanings can vary so much and describe things 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 bast 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 “Father of Taxonomy” himself, Swedish botanist Carl Linnaeus, got his surname from his father who was required to take a permanent surname upon entering the University of Lund in the late 1600s. His father chose a Latinized version of ‘linden’, based on a huge, old linden tree growing in the local area of his childhood.

The genus Populus refers to aspens, poplars and cottonwoods, all classified along with the willows 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 which stands out so prettily in contrast to the leaf top’s dark green. 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.

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 and twisted which causes them to tremble and flutter in the slightest puff of breeze. This is how Carl Linnaeus came up with the genus name. In Latin, populus means ‘people’, and to Linnaeus the continual rustling of poplar 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 language offers up an interesting compilation of tree 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 and then head to the trees by the historic streetcar station (which is also the district office). That is my hope, anyway. Given the time allotted, the goal for the day suddenly feels both overwhelming and yet still possible to attain. I take a breath and decide to just enjoy things, not worry about what doesn’t get completed. Walking companionably, the two of us are quiet for a moment, just looking around and enjoying the day. As we round the curve of the pedestrian path we exit the shade of the evergreens to step into the sunlight of the open parking lot where the alternately green and white leaves of white poplar catch my attention. They are waving from their magnificent trees, beautifully reminding me that they are next in line for our work today.

Shortly after my dad died, I was looking over his bookshelf when my eye fell upon a small tree ID book. My hands immediately reached over to pull it out. Flipping through, I found a leaf pressed between the pages where the book easily opened. The leaf was actually one leaflet taken from the compound palmate Ohio buckeye, pressed in the buckeye page (of course!). Surprised, I let this sight soak through me for a while, pleased to have found an artifact my dad had placed here with his own intent. It reminded me of his interest long ago in our yard’s buckeye tree I had identified. Perhaps it was even from that one! My heart warmed at 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. The 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 belongs to attractive leaves of what I now know to be 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 because the city foresters have removed all those trees from the park. Locating the rest of the list, however, was meaningful to me. It connected me to 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 first and 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. With willows, things can get a bit complicated. It’s just the way willows are. For, 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 three of these nonnatives 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 (or perhaps because of) all this, willows in general seem very well adapted. Their natural variability is their strategy to get 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 my own neighborhood. 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”, the list reads. When I was first scoping things out for our work today, white poplar was easy to locate. Black willow (Salix nigra), second on the list, was more elusive. I had learned it prefers moist soils, which makes sense why it is on my dad’s list for this pedestrian path area along the lakeshore. Many willows, I had also learned, have a very pale underside to their leaves in contrast to deeper green leaf tops; black willow, on the other hand, presents both sides of its leaves as pretty much the same shade of green — one very good way to ID them. A huge willow grows right next to the pavilion, but its leaves show light yellow green on the underside so I quickly dismissed that one.  After bushwhacking here and there along the somewhat overgrown lakeshore to get up close to the willow trees there, I gave up. While my first attempt to scout out black willow ended in failure, I did make the connection to the sucker sprouts my dad and I planted lakeside to the family cabin in northern Minnesota back when I was a teenager. Out of all the suckers we planted those many decades ago, only one survived. That one I now know is a black willow, and it truly is a survivor. Many years earlier, beavers had chewed about halfway through the trunk, then stopped, leaving a big gap. The tree had gone on through the decades growing around the gap leaving a big scar as the only sign left from beaver activities as it recovered and flourished. Today that black willow has grown into a 14″ diameter beauty.

As Susan Jane and I approach the two white poplars growing by the lake, I show her which one I think will work best. A small path through the underbrush and grasses leads to each, but one of the white poplars is more visible from the pedestrian path than the other. We think a tag on that more visible 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 head 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 today or tomorrow and keep searching until I find it.”

She knows neither about the backstory of the list nor of my determination to find the tree species on it. I plan to locate the black willow later this week and wire the ID sign onto what I’m pretty confident will be a clump of smallish trunks. Black willow is not an especially tall tree, though it can attain 20″ in diameter. Based on my false starts so far, I expect it will take more bushwhacking through the underbrush than I had bargained for. 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 just a few feet away on the paved path. Like before, I will once again studiously ignore them as I know they are studiously ignoring me in return. The urban way to get along after all!

So, having decided black willow can wait a bit, 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, ironwood, and American beech are perfect examples of this.

Blue beech (Carpinus caroliniana) is a very touchable tree with thin, gray bark that seems to invite hands to run along its smooth, sinewy surface. For this reason, it is also called ‘musclewood’. Blue beech is also known as American hornbeam due to the extreme hardness of its wood and a fine grain that polishes up to resemble horn. ‘Beam’ means ‘tree’ in Old English. Here’s where things get tangled. Blue beech 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 (Fagaceae) 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. Like all birches, these two species have catkins, similar leaves, and both male and female flowers occur on the same tree. 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 roughly 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.

To further confound things, American beech (Fagus grandifolia) is often confused with blue beech. This mix up is due to a slight similarity between the leaves, and to a much greater extent because of their shared quality of having smooth, gray bark. Both tree trunks are similarly inviting to touch. American beech, however, produces true nuts, and is classified in the Fagaceae family along with the oaks and chestnuts. Besides the fact that American beech is a much larger tree than blue beech (up to 70′ tall with a trunk diameter than can get to 3′ across), a very easy way to distinguish between the two species is to compare their winter twigs when there are no leaves to get in the way. The narrow buds of an American beech are so long (up to 3/4″) and so widely angled away from the twig that they almost resemble thorns. Once you know what to look for, you can also locate these buds in summer. No matter the season, making the ID this way is unmistakable.

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

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

It smiles back at us in the midday sunshine, perhaps not flexing its muscles like a blue beech does, but in comparison its smooth bark coming pretty close.

“Susan Jane,” I say directly, “I can’t mar this beautiful 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 into this tree. Swamp white oak is only about 15 feet away and is easily dispatched, forcing us to retrace our steps back to the American beech again. The extra time, however, seems to have solidified things for us. We walk around the tree once more, but we both already know the sign should face towards the nearby swamp white oak sign we’ve just attached.

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

This is the point at which the nails bend as the hard wood of American 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 American beech and is much more visible alongside the street and walking trail. An abundant grove thrives there, 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 cones female juniper produces look like tiny blue berries, but they are not berries at all. In the grocery store, however, they are referred to as ‘juniper 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 also offers another example of common names confusing things. Just like our friend we met in chapter 5, northern white cedar, eastern red cedar is not a true cedar either. The genus name, Juniperus, tells us 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. He always knew how much I love wood, and respected my creative proclivities that also extend into the use of saws, drills and hammers.

“Maybe you could cut these into coasters,” he said those many years ago, handing me a rough log, “or to use as aromatic pieces you could 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 about trees and sharing so many aspects of that knowledge with others. I didn’t know it at the time, but my science professor dad who loved to teach and encourage others, had already begun sharing his wonderful legacy with me.