The Weird Ones

Early fall was a time of vibrant colors and lots of action. Colors have faded a bit now. If you have lived in the north for a while, you may have come to appreciate the subtle gold of a tamarack swamp, or the rich browns in a grove of oaks as they extend the fall color season. But have you ever stopped to think about how weird those two trees are?

Tamaracks are conifers, bearing their seeds in cones just like their relatives the pines, spruces, and firs. But conifer isn’t our first choice word for describing pines – we’d rather call them evergreens. When we do that, though, tamarack doesn’t fit. It is the only deciduous (losing its leaves seasonally) conifer in Wisconsin. Oaks, in contrast, are in a group known as broad-leaf trees, most of whom are deciduous. Yet oaks cling to their leaves.

Why would a tamarack lose its needles? Why would a pine keep its needles? And why does the oak keep its dead leaves?

There is adaptive value in each strategy, otherwise they would not persist. Needles are really just modified leaves, better suited to low nutrient, low moisture situations. They have basically the same parts as a maple leaf, but everything is more tightly packed and protected. The stomata (pores for gas exchange) hide in a groove, protected from dry winds. A waxy outer layer helps to prevent water loss. By retaining green, chlorophyll-filled leaves all year, evergreen trees can take advantage of any warm days to photosynthesize, and save themselves the trouble and nutrient expense of growing new leaves each spring. They replace only about a third of their needles per year.

On the other hand, broad-leafed deciduous trees, like maples, grow large leaves with a lot of surface area for photosynthesis. The broad leaves also result in a lot of water loss. This is fine when it is raining, but not when it is frozen. Although trees use enzymes to protect leaves from freezing while they are still photosynthesizing, that only works for so long. Then, frost-damaged leaves would be a liability as an entrance for disease.

Why would tamarack combine the two strategies and lose its needles?

Well, we don’t know for sure, but my favorite theory is that it has something to do with how far north the tamarack’s range extends. On the Winter Solstice this year, Duluth, MN, will only have 8 hours and 32 minutes of sun. In Fairbanks, Alaska, near the northern edge of the tamarack’s range, the sun will shine weakly for 3 hours and 42 minutes. Most of the tamarack’s habitat is in the middle of that range. What good are green needles if there is little sunshine? By building more delicate needles that don’t have to withstand harsh winter conditions, tamaracks can save a little energy.

Tamarack needles and cones. Photo by Emily Stone.

Likewise, what good are the dead, brown leaves of an oak, even with sunshine? Oaks are a broad-leaf tree, but, oddly, they hang onto their leaves until heavy snow knocks them off. Most deciduous trees (including tamaracks) cut their leaves off by growing a protective abscission layer on the end of the twig, and then encouraging the leaf to skedaddle with digestive enzymes or a new layer of cells.

In contrast, oak leaves start to grow an abscission layer soon after new leaves form, but do not finish the process until the next spring. Scientists call this retention of dead stuff “marcescence.”

Plant physiologists agree that marcescence is a juvenile trait, associated with young trees and newer branches. This makes sense, since the young aspens in the field near my house are still holding onto their leaves. And understory trees, which tend to be younger, always seem to change colors later in the fall.

Marcescence also may be juvenile in terms of evolutionary history. In southern regions, some oaks are evergreen. Our northern oaks may be in transition from being fully evergreen to being fully deciduous. Maybe they are not done yet…or maybe they like where they’ve paused!

Although there are tasty new buds waiting to come out in the spring, this year’s dead, dry, crinkly oak leaves are not very palatable, and that may deter deer and moose from nibbling on the new growth. The tardily deciduous aspens probably gain that benefit, too.

Red oak leaves. Photo by Emily Stone. 

Another hypothesis is that the oaks are saving their leaves until spring. When the leaves fall, they will provide the tree with nutrient-rich mulch for the growing season, instead of the leaves decomposing throughout the winter. The leaves dangling from lower branches may also act as a snow fence, trapping extra moisture for the tree.

Of course, there is no way for us to know for sure just what the oak is “thinking” as it rustles its skirt of leaves in the middle of a blizzard. Nor do we understand what the tamarack is “planning” when it turns golden, and then bares its knobby twigs for the winter.

As with humans, the weirdest organisms are often the most interesting.

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too.

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Our exhibit: “The Northwoods ROCKS!” is open through mid-March. Our Fall Calendar of Events is ready for registration! Follow us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.

Lovely Slugs

These damp, gray days of fall can get a little dreary sometimes. When I don’t have time for a big hike, I take my camera for a walk along my driveway. Strolling slowly, I let my focus soften as I wait for something to catch my eye. Earlier this month, a lichen-covered stick, brought to earth by precursors of the gales of November, made me pause.

Dampness cooled my fingers as I lifted softened wood out of the limp maple leaves. In order to make sense of the small log, I assumed the hunched posture of nearsighted people everywhere. My field of vision narrowed, and I became immersed in an alien world. Orange, gray, brown, yellow, wrinkled, dusty, lumpy, smooth, round, and branching, the variety of shapes and colors colonizing this stick were dazzling!

In various outdoor teaching resources, I’ve read about an activity called a “micro hike,” where students are given a short string and told to blaze an ant-scale trail across the forest floor. Although I have a baggie full of yarn strands in my teaching tools, I’ve never found the time to pull them out. Now, both my eyes and my camera bushwhacked across the lichen-covered barrens of the stick, forging a path of discovery.

Suddenly, something wet and shining loomed ahead. As I watched, the slug extended their beige-colored form and undulated across the lichen field on their single, body-length foot. Their movement was surprisingly graceful. When I looked up the species, the name was lovely, too: dusky arion. Never mind that they are introduced from Europe and often become garden pests. I’ll resist judgement if they resist my tomatoes.

Slugs don’t see the world; they touch, and smell, and taste it. The four dark tentacles—two short ones down low, two long ones on top—stretched and explored with delicate fascination. Using pale, glossy lips infused with chemoreceptors, the slug gently touched and recoiled from the lichens’ wrinkled surfaces. Yeasts sometimes join the lichen partnership and produce antifeedant chemicals to repel herbivores. The slug’s lips may have been sensing those.

A few times, the slug seemed to pause and gum the lichen, like a toddler trying a new food. Were they using their sandpaper-like tongue called a radula to scrape up algae who had colonized the lichens’ many surfaces?

When that slug reached the end of the stick, I put them down and picked up another section of the fallen branch with yet another slug glued to its surface. This slug wasn’t traveling, but they were moving. The slug squeezed and contorted their whole head region, and opened and closed a hole in their side. Out of that hole snaked a string of mucus with little brown dots suspended within. Slug scat!

The scat was extruding from near the slug’s head, and there’s a perfectly reasonable explanation for this. Slugs are evolved from snails, and a snail’s anus must be located far enough forward on their body to easily get the poop outside of their shell. The trait has carried through.

Why would a slug get rid of the beautiful, cozy, humidity-controlled, predator-resistant house that snails still possess? Shells require a lot of calcium to build, which is in short supply in our sandy soils. Shells also prevent their owner from squeezing into hiding places like soil tunnels and rotting logs, two habitats that contain enough moisture for a slug to survive. The loss of a shell broadens a slug’s options, and in the Arion genus, all that is left are a few calcareous grains under the rear of the mantle.

Laying that slug and stick back on the ground, I picked up a new one. This slug was resting even more tranquilly. Only their pneumostome (which translates to “air-mouth”) moved. The small, football-shaped holed opened to let in air, then slowly closed, then opened again. When a daddy longlegs explored too close and stepped on their mantle, the slug squeezed their pneumostome shut as we might scrunch up our whole face in response to a tickle.

As this dusky arion slug rests on a lichen covered stick, noticed the undulating foot along the length of their body, as well as the mantle of different textured skin near their head. You can barely see a tiny dimple that is their closed pneumostome or breathing hole. Photo by Emily Stone.

These first three slugs were all roughly an inch long, but farther down my driveway the whimsical yellow cap of an Amanita mushroom caught my eye, and on its creamy white stem were three smaller slugs, half as long and much more slender. Babies! An individual slug, at least in the Arion genus, lives about a year. Eggs hatch before winter and they hibernate as teenagers, then become active early in spring—in the mirror image of this cool, damp weather—to finish growing up. Slugs are hermaphroditic. When they find a partner, they each inseminate the other and both lay eggs. Then, often, they die.

Baby slugs on an Amanita mushroom

Standing to straighten my back, I was surprised to find how short my walk had been. Having explored through the exotic tufts of lichens and mosses, and observed these alien creatures, I felt like I’d been in another realm. And soon, those slugs will be entering another world I’m curious about. As they make plans to spend the winter hunkered down beneath the snow, I’m making plans to follow them into the Subnivean Zone. I’ll be sure to tell you what we find.

For videos of these three slugs, check out the Natural Connections Nuggets playlist on the Cable Natural History Museum’s YouTube Channel.

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too.

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Our exhibit: “The Northwoods ROCKS!” is open through mid-March. Our Fall Calendar of Events is ready for registration! Follow us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.

Midnight Mystery Sound

Chiiiiirrrrp!

A single, loud noise rang through the dark. My eyes popped open. “I don’t know what that was,” I whispered into the tent.

“Well, it’s never good when the naturalist doesn’t know what made a noise,” joked my friend as they rolled over, sleeping bag rustling. While they fell back to sleep, I scrolled through a species list in my head. Still, no luck in matching the sound to an animal I’d heard before. But wait, a few years ago I watched a couple videos of cheetahs chirping. Do other big cats—like cougars—ever chirp? I wondered. (Yes!)

A poem Mary Oliver wrote about seeing a bear track popped into my sleepy brain. “But not one of them [stories about people seeing bears] told what happened next—I mean, before whatever happens—How the distances light up, how the clouds are the most lovely shapes you have ever seen, how…Every leaf on the whole mountain is aflutter.” And indeed, the thought of a cougar in the forest made it feel just a little more alive.

Deciding not to worry about it, I also rolled over and let the steady rasp of beaver teeth from across the bay lull me to sleep. This was the first night of a quick weekend trip to the Boundary Waters, and I wanted to thoroughly enjoy my stay at the best campsite on Winchell Lake.

We woke up to a white-shrouded dawn, but a stiff breeze chased the mist away while we ate breakfast on the beautiful rocky point. The wind I’d listened to all night had returned in full force. Not wanting to linger and let the waves build even more, we packed up camp, loaded the canoe in the lee of our point, and struck out down the lake.

Despite the lateness of the season, we spotted a few different solo loons bobbing in the waves, identifiable by their distinctive silhouette. The sun’s glare off the choppy water made it difficult to tell if they were adults or juveniles, but either way they still had plenty of time to migrate before ice-up.

Despite the headwind, we made good time on another big day of travel. After a late lunch at our new campsite on Caribou Lake, we swam, and set up camp, and pulled out Devotions by Mary Oliver. “And to tell the truth I don't want to let go of the wrists of idleness, I don't want to sell my life for money, I don’t even want to come in out of the rain.” The wind slackened with the setting sun, and we were soon enveloped in layers of darkness, nylon, and down.

Chiiiiirrrrp!

The mystery noise had followed us! But since we survived it the previous night, I assumed we’d survive again.

Sure enough, we woke to another white-shrouded dawn. Just off our campsite, the silhouette of a water bird faded in and out of the fog. Our visitor’s pointed bill and graceful neck were reminiscent of a loon, but their overall stature was more petite and delicate. Just like a loon, the bird thrust their face beneath the waves to peer beyond the surface glare. Seeing something tasty, they dove gracefully and then reappeared. Then, chiiiiirrrrp!

We looked at each other and laughed. Here was the source of our midnight mystery sound.

By the general shape and size, I was pretty sure that the waterbird was a grebe. Like loons, grebes dive to avoid danger and to catch fish, which they swallow head-first underwater, and have legs so far back on their bodies that they are awkward on land. Their newly hatched chicks also find refuge on Mom or Dad’s back.

Unlike loons, grebes sometimes emit a single, loud chiiiiirrrrp! Grebes also have lobed toes instead of webbed, and ingest a lot of their own feathers, which form two separate balls inside their stomach. Scientists think that the feathers may protect their digestive tract from sharp bones or fish spines. Grebes have more habitat flexibility than loons, since they are able to take off from smaller lakes, and they build up open, bowl-shaped nest structures on emergent plants or in shallow water, and therefore don’t have to rely on finding the perfect shoreline location.

Based on my Sibley Guide to Birds, my memories of the bird, fuzzy smartphone photos, and encounters in previous years, I think this neighbor was a red-necked grebe. They breed mostly in Canada and Alaska, but can also be found on shallow lakes in northern Minnesota. While they migrate through the Great Lakes, grebes tend to spend the winter on the shallow estuaries and bays of northern New England.

A red-necked grebe spotted on Alton Lake in late August 2020.

The grebe had disappeared by the time we finished breakfast and packed up camp, but the thought of that little bird being the source of the mystery sound made me chuckle several times as we paddled out. With just one odd note, that grebe had created a permanent place for themselves in my Boundary Waters memories.

The final portage into Poplar Lake.

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too.


For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Our exhibit: “The Northwoods ROCKS!” is open through mid-March. Our Fall Calendar of Events is ready for registration! Follow us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.

Listening to a Boundary Waters Night

Wind whooshed through the pines and spruces who bristled across the spine of our rocky point like quills on a porcupine. I snuggled more deeply into my sleeping bag. The day had been gusty, our paddling fierce and steady against whitecaps, with white lines of foam streaming down the lakes. Once the sun rose again, we’d be paddling upwind into a three-and-a-half mile fetch. Would the breeze slacken or strengthen overnight? I tensed at each gust and relaxed in the quiet, trying to foretell the future.

You would think that after 25 years of paddling in the Boundary Waters Canoe Area Wilderness, I’d be pretty good at sleeping in a tent up there. But no, I often find myself listening in the dark. Sometimes the vigilance is because I’m responsible for the safety of a group. Other times it’s just a by-product of a sore back or snoring neighbor. Cracks of thunder and howling winds are the only sounds that truly carry a measure of risk. But even quiet nights find me lying awake. It’s not all bad.

During a pause in the wind, the faint rasp of gnawing teeth slipped through the thin nylon walls of my tent. Micro-bears (mice) might not be dangerous, but they do have the potential to ruin gear or my treasured bag of gorp. I opened my eyes in the darkness and tried to imagine the campsite layout. Was the sound coming from our food pack, hung high in a white pine tree away from regular bears? Or was it coming from under the rain tarp, where a few items of gear were avoiding the off-and-on drizzle of the evening?

Then my tent-mate’s bladder chimed in on the problem. When they started undoing the series of zippers – there is no silent way to open all of those zippers! – between them and night air, I decided that I might as well get up, too, and take care of a couple of sleep deterrents at once.

Relieved, I determined that the gnawing was definitely not coming from within our campsite. In fact, it seemed to be coming from across a small bay. Sound travels astoundingly well over water, but still, those had to be big teeth to make a sound that would carry. I smiled at several memories of hearing this same sound at different campsites – beaver!

Since we were up, and the moon was up, and the wind was down, we grabbed jackets and headlamps and made our way down to the point. This slightly sloping spit of rock on Winchell Lake, with its level landings and artistically disheveled jack pine trees, is the foundation of one of the most desired campsites in the Boundary Waters. When I worked for the Forest Service in this area, we never saw this campsite empty during the height of summer. This afternoon it had been our reward for braving the wind and rain when almost no one else did.

We spoke in whispers while slipping the canoe into the water. The moon played peekaboo with the clouds as we turned into the bay and paddled toward the dark shadows of the trees. Then we paused to listen. Paddles dripped. Waves lapped gently against Kevlar. And there it was: a rough and rhythmic gnawing from the far shore. We paddled a few strokes closer.

Splash! Shriek! Laughter.

I’d been expecting a beaver to slap their tail at us, warning their family that something suspicious was afoot. I’d been trying to brace for it. But when the noise actually came it startled an embarrassing noise out of me all the same, and I shook with mirth in the dark. Four more splashes, conducted in surround-sound, told me that we we’d probably disturbed this family of beavers enough for one night.

After the screech of zippers, the rustle of sleeping bags, and the hiss of breathing subsided, my ears again found the rasp of beaver teeth on wood cutting through the night air. Now, because I knew our food and gear were safe, the sound was soothing and familiar. Darkness began to seep behind my eyelids, too, and quiet the synapses that kept me awake.

I wonder if Sigurd Olson, champion of wilderness, once slept at this campsite? If he travelled through Winchell, he surely did. A bit of wisdom from his book Reflections from the North County, filtered through my drifting memory: “If we can somehow retain places where we can always sense the mystery of the unknown, our lives will be richer."

Chiiiiirrrrp! 

A single, loud noise rang through the dark. My eyes popped open. “I don’t know what that was,” I whispered into the tent, not very much liking what this mystery of the unknown suddenly added to my life.

But that’s a story for next week.

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too.

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Our exhibit: “The Northwoods ROCKS!” is open through mid-March. Our Fall Calendar of Events is ready for registration! Follow us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.