Just Ducky

The bitterly cold wind numbed my cheeks, stung my eyes, and blasted my half inch of exposed forehead with an ice cream headache. Happily, the sun was shining and the rest of my body—entombed in layers of wool and down—remained a comfortable temperature. As they say, there is no bad weather, only bad gear. I felt adventurous to be out walking on this sub-zero day, even though the temperature had risen a full 14 degrees from -17 to -3 degrees Fahrenheit.

With the wind at my back, an ethereal sunset glowing on the horizon, and a warm house waiting less than two miles ahead, I decided to take Duluth’s Lakewalk along the shore of Lake Superior. Ice and snow mingled with rocks on the beach, and although no ice floated in the lake, the water looked frigid just the same. NOAA data shows that the temperature in this corner of the lake is about 40.5 degrees, which is just a tad warm for late December.

As I rounded the corner by Endion Station, I was surprised to see life. Dozens, maybe hundreds, of mallard ducks huddled in rafts along the leeward shore, the iridescent green heads of the drakes shimmering handsomely in the last rays of sun. They looked especially dapper against the pure white patterns of ice-draped riprap. The presence of this concentration of life somehow made the afternoon feel warmer.

Don’t ducks migrate south for the winter, though? Well, as with so much in nature, it depends. Mallards are medium-distance migrants, who only go as far south as needed. Some do fly all the way down to Mexico and the Caribbean, but many seem to prefer a “staycation.” About 1,500 mallards even make Anchorage, Alaska, their year-round home! As long as the ducks can find sufficient food, they can withstand some pretty brutal winter weather.

In species of songbirds who are medium-distance migrants, such as red-winged blackbirds, and juncos, it tends to be mostly males who overwinter farther north. For them, being the first back on their summer breeding territory is of utmost importance.

That’s not the case for mallards. Although this flock seemed to have a few more males, that’s likely due to a male-heavy skew in the overall population. Male and female ducks need to overwinter in mixed flocks, because that’s when they choose a mate and form pair bonds. In spring they arrive on their breeding territory together. Once copulation is complete, though, the males disperse. The female incubates the eggs and protects her clutch of fuzzy nuggets all by herself. (Insert your favorite joke about lazy males here.)

Continuing up the ramp to where the path parallels the railroad tracks, I looked down into a small pool—hidden in the riprap—that seemed to be at the outlet of a culvert. Here, out of the wind and in water that was potentially slightly warmer, ducks carpeted every surface. Pulling my scarf up over my windward cheek, I stopped to watch.

Some ducks floated with their beaks and heads tucked backward under their wings. My rosy nose was envious. Other ducks paddled idly in circles, perhaps a little off-kilter because one foot was being warmed up in their feathers. Occasionally one or two ducks would start dipping their heads quickly and letting the water slide cleanly off their backs. It didn’t match the feeding behavior I’ve come to expect from dabbling ducks: pointy tail sticking straight up in the air for several seconds while their beak probes the bottom. Mallards use a similar dipping motion in their courtship rituals, but that looks more like a head bob than this dolphin dive. It reminded me of how I feel in an outdoor hot tub, constantly submerging myself in the water to stay warm. Could it be that the ducks are using the “warm” water (more than 40 degrees warmer than the air!) to help maintain their body temperatures?

Plenty of ducks weren’t even in the “warm” water; instead they huddled on a small shelf of ice at one end of the pool. They looked cold. But looks can be deceiving. Mallards are big-bodied ducks, and well able to maintain their 100-degree body temperature. All of our winter parkas imitate their fluffy, warm, down feathers protected by a waterproof shell. We can’t even come close to imitating their feet, though. Not only are webbed duck feet adapted to swimming, they are adapted to manage heat loss as well.

Mallards have blessedly few nerves in their feet. They don’t seem to feel the excruciating pain of too-cold toes warming up. The discomfort that humans feel is actually a helpful adaptation, though, and inspires us to warm up our feet or hands before they are damaged by the cold. Ducks don’t need that motivating pain to keep their feet safe. They have a net-like pattern of veins and arteries in their feet, called “rete mirabile,” which is Latin for “wonderful net”. This wonderful net allows cold blood returning from the feet to be warmed up by outgoing blood before returning to the body. Ducks will increase or decrease blood flow to protect against tissue damage while losing as little heat as possible to the environment. They may not feel as cold as they look!

Flocks of mallards in the open water near Duluth are a common winter phenomenon, at least in recent memory, and they seem to have the adaptations to handle an Arctic blast. I think they probably would agree that there is no bad weather if you have the right gear.

Special Note: Emily’s book, Natural Connections: Exploring Northwoods Nature through Science and Your Senses is here! Order your copy at http://cablemuseum.org/natural-connections-book/.

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! Our new phenology exhibit: “Nature’s Calendar: Signs of the Seasons” is now open.

Silver Lining

Perfectly firm, freshly groomed tracks cradled our skis. Bright sun warmed our faces despite an occasional breeze. A sinuous, brown and white river caressed our looping length of trail. And a half-tunnel of arching tree branches cupped us in their arms. The River Trail at ABR ski touring center in Ironwood, MI, was treating us well for this first long ski of the year.

I paused at an intersection to let my companions catch up, and found myself admiring a line of trees perched on the bank of the Montreal River. Each tree was actually a cluster of trunks, united at the base and spreading gently out toward space and sunlight like a giant, woody bouquet, with bright snow accentuating each curve. Round, red buds adorned the tip of each oppositely arranged twig, giving its crown a polka-dotted look. Gliding up, Abett asked about the tree, and I shared “silver maple” as my identification. We all admired their form.

Silver maples are classic floodplain trees in Wisconsin, and this wide, flat area along the Montreal River is perfect habitat for them and for easy ski trails. In its other reaches, the Montreal River cuts through cliffs, crashes over waterfalls, flows under the deep shade of conifers, and pours out on to a rocky Lake Superior Beach. The Ojibwe name for the river is Gaa-waasijiwaang, meaning “where there is whitewater.” It’s true that most of the water I see is white, but for a different reason. Here, (as far as I can tell under the snow) it meanders through alder thickets and grassy meadows that are soggy when not frozen.

While the dark, tannin-stained waters of the river look innocuous where they peek out through holes in the ice, they probably aren’t always so well-behaved. I cite the trees as my evidence.

The tight grouping of trunks exhibited by these silver maples is a common form among floodplain trees, and is shared by basswoods, too. Silver maples drop their helicopter seeds (the largest of any maple) in the spring. The seeds may get a wild ride to a new home if there is a flood, and the well-provisioned little explorers germinate immediately. In the moist, rich alluvial soil of the riverbank, they might spend a season or several growing straight, tall, and independent. Until another flood comes. Debris, logs, and even ice churn down the river and over its banks. The little tree doesn’t have much of a chance.

Luckily, silver maples—especially small trees less than a foot in diameter—can resprout prolifically from their stump or root crown. With an established root system already in place, I bet the second round of sprouts grows even faster than the original. By the time the next flood hits, the trees are already in defensive position, with the upstream trunks shielding the downstream trunks from damaging debris.

The roots of a silver maple aren’t just important for resprouting after damage. Any plant that lives near water needs to be adapted to having its feet wet. Even roots need oxygen in order to carry out respiration and grow. On the other side of the trail, a thicket of speckled alders takes in extra oxygen through the many lenticels (“speckles”) in their bark. They transport that oxygen to their roots. Earlier, we’d skied under a big, arching willow tree with its gnarled branches and graceful, yellowish twigs reaching all the way over the trail. Willows also use lenticels to breathe. Silver maples take a different route, and send a shallow root system near the surface where there is more oxygen.

Despite growing right next to the river, these silver maples were actually perched on slightly drier soil than you’d find a few yards inland. When a river floods, the moment its water spills over its banks, it slows down and deposits the biggest pieces of its suspended load—sand. This process builds a raised bank—a natural levee—between the river and its floodplain. So, instead of dipping their toes in the soggy muck beyond, the silver maples lined up on the natural levee can take advantage of both well-drained (and oxygenated) sandy soil, and the proximity to water. Meanwhile, their fortress of trunks protects them from the river’s fury. This is yet another example of teamwork in a forest.

Our little team of skiers continued on shortly, after exclaiming a few times about the beautiful weather, the perfect grooming, the fine company, and this gorgeous scenery. There wasn’t a cloud in the sky, but our ski even had a silver lining.

Special Note: Emily’s book, Natural Connections: Exploring Northwoods Nature through Science and Your Senses is here! Order your copy at http://cablemuseum.org/natural-connections-book/.

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! Our new phenology exhibit: “Nature’s Calendar: Signs of the Seasons” is now open.

Snowflake Birds

Big, fluffy, wonderful snowflakes swirled around my head and the stiff breeze sent icy fingers down my neck. Slamming the car door against the storm, I started the engine and wished the temperature gauge would rise above cold so I could turn on some warmth. My cross country skis were rattling around behind me—ready, but unused—so I was ecstatic about this storm, but the cold was still a shock to my system.

Rolling along the highway at a relaxed, “get-there-safely” pace, I enjoyed the scenery’s face lift. Drab, brown fields have been transformed, and the forests are delightfully frosted. Tawny, dried weeds and their dusky shadows painted texture on the roadside border, which gave way to glittering fields of smooth white. Suddenly, those colors came alive in a cloud of swirling beauty. Brilliant white, sharp black, brown, and blur; the flock of snow buntings ascended, swooped as if tossed by blizzard winds, and flashed their colors in unison as I passed.

The warm brown srtipes on snow buntings are only temporary, and are confined to just the tips of feathers. All winter, the male rubs his feathers on the snow, wearing off the brown tips and revealing his dapper white and jet black courting suit by the time breeding begins. Females also rub off most of their brown tips. Photo by Charles J Homler, creative commons.

These tough little visitors from the Arctic live up to their nickname of “snowflake birds.” They nest on tundra all around the top of the globe, and are the most northerly recorded songbird in the world. In fact, one scientist claims that “Under the current climate conditions of the Arctic, there is no northern range limit for snow buntings.” There is a southern limit to their range, though, since a certain amount of daylight is essential to their reproductive success. They also require the average temperature in July to stay below 50 degrees F. That may sound unpleasant to you, but it comes with midnight sun, a warm down jacket, and the stark beauty of places like Ellesmere Island, Greenland, Norway, and Siberia.

In winter, some snow buntings (especially females) head as far south as Iowa or Utah, but some (especially males) migrate only as far as northern Canada. Moderate cold isn’t an issue. They can survive in temperatures down to -40 degrees F. Only when it gets down to -58 degrees F does their body temperature start to plummet. The solution? Dive into a nice, warm snowdrift. The insulating power of snow helps preserve their body heat and keep out the wind.

My toes get cold just thinking about it, but feathered feet allow snow buntings to spend most of their winter strutting about on the chilly drifts. They usually feed in big, gregarious flocks that seem to roll along chaotically as the birds in the back make short, fluttering flight to the front. Occasionally, the whole group will rise and fall in a flurry of motion at the suspicion and passing of danger. Feeding flocks are entertaining to watch, since these birds don’t submit to a defined hierarchy like chickadees do, and end up bickering continuously over seeds and space.

Deep snows cover up the seed heads of short tundra plants in their breeding territory, but here in Wisconsin, snowplows expose seeds in the gravel shoulder, and windswept fields of nodding stems offer good foraging, too. I was particularly happy to read that they eat seeds of the ragweed plant, which is a major cause of seasonal allergies!

Naturalist John Burroughs wrote that snow buntings have “plumage copied from the fields where the drifts hide all but the tops of the tallest weeds, large spaces of pure white touched here and there with black and gray and brown.” But some colors are only temporary, and are confined to just the tips of feathers. All winter, the male rubs his feathers on the snow, wearing off the brown tips and revealing his dapper white and jet black courting suit by the time breeding begins.

This is an odd way to get dressed, for sure, but it saves valuable energy that would be spent on the usual second molt. And energy is at a premium in spring. Snow buntings must gain at least 30% more body mass before beginning their northerly migration, and individuals without adequate energy storage don’t seem to be able to “select seasonally appropriate directions during their migration.” In other words, skinny birds can’t find their way home. Perhaps this keeps them in warmer regions until they have gained enough strength to migrate.

The ones that do head north fly at night and use the geomagnetic field of the Earth almost exclusively for wayfinding. Visual clues are of little use to them in the blank, white of the tundra. Males arrive on their breeding territories in early April, when temperatures can still drop to -22 degrees F. They have to arrive early to secure a good territory, since the cracks and cavities in rocks where they nest are a finite resource. Females, sensibly, arrive six weeks later. He woos her by singing fast and often—a signal that he is an efficient forager and has ample free time for lovesick serenades. That’s important, because she must incubate the eggs almost continuously to keep them warm in the cold rocks, and relies on a fast-foraging male to feed her during that period.

The breeding season is a long way off, but today it feels like the snow buntings have brought the tundra south with them. I would agree with John Burroughs, who described them as “the only one of our winter birds that really seems a part of winter, that seems to be born of the whirling snow, and to be happiest when storms drive thickest and coldest…”

Arriving at the trailhead, I emerged into the swirling flakes, clicked into my skis, and attempted to embody the spirit of our tough, adaptable snowflake birds.

Special Note: Emily’s book, Natural Connections: Exploring Northwoods Nature through Science and Your Senses is here! Order your copy at http://cablemuseum.org/natural-connections-book/.

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! Our new phenology exhibit: “Nature’s Calendar: Signs of the Seasons” is now open.

Wood Wide Web #2

Winter is coming in fits and starts. Last week, a thick, white blanket of snow separated each stoic tree trunk. Then it melted. This morning, a thin frosting of damp flakes swirled out of the sky, outlining every feature of the forest floor, highlighting the trunks and tracing the twigs. The intricate patterns, thus revealed, give us just a glimpse of the complexity that lies beneath. Yes, the roots of the trees ramble widely, and fuse with relatives to form a Wood Wide Web that shares resources, but the connections don’t stop there.

Light snow traces the complex network of twigs in the forest, and we can imagine an even more intricate web of roots and fungi living below the surface. Photo by Emily Stone.

Fungi pick up where the roots leave off. Most tiny root tips are colonized by filaments of fungi, which extend the plants’ reach into the surrounding soil. Each tree species can host multiple types of fungi, and each fungus can colonize a variety of plant species. This expands the network beyond the species-specific root grafting, and creates a mycorrhizal (myco=fungus; riza=root) network that is robust and thickly woven. So thickly, in fact, that scientists say you could find seven miles of fungal hyphae in a pinch of dirt, and hundreds of miles under a single footstep.

When Dr. Suzanne Simard (a forest ecologist from the University of British Columbia who coined the term “wood wide web”) used DNA to identify all the individual trees and fungal strains in a forest plot, she ended up with a diagram resembling the airline route map in your seat back pocket. A big, old, well-connected white pine is like Chicago O’Hare, because it provides connections to lots of other places. Hub trees connect (through the mycorrhizal network) to other hub trees, as well as younger, more isolated trees. This pattern is incredibly efficient. The two most distant trees in her study plot only needed two “flights” to connect, and the maximum path length the researchers discovered required only three “flights.”

In addition, this pattern creates resilience. With just a few important hub trees (or airports), there is a lower likelihood that one of them will be damaged. If one of the less-connected trees dies, the impact on the ecosystem isn’t large. However, in the infrequent event that one of the few hub trees dies, the impact on the connectivity of the surrounding forest could be dire. That’s why conservationists and foresters must focus on identifying and preserving the venerable elders.

Trees and mycorrhizal fungi live in an incredible symbiosis. Trees feed the fungi sugars produced during photosynthesis, and may share up to 80% of their total production. In return, fungal hyphae increase the absorbing area of roots from 10 to 1000 times. This protects trees against drought by contributing to water uptake and storage. Fungi don’t just absorb nutrients; they actively break down tightly bound soil nutrients like phosphorous and iron and make them available to plants. Some fungi even recycle nitrogen from soil nematodes into their plant hosts. Fungi and trees feed each other, and the intricate web captures and holds nutrients before they can be lost from the system.

The benefits aren’t just food related. The sheath that a fungus forms around a root creates a physical barrier against diseases. Meanwhile, it is diverting heavy metals and excreting antibiotics designed to kill pathogens. At a community level, the fungi act like fiber optic cables. Using warning chemicals and electrical impulses, they help trees share information about insects, drought, and other threats, so that currently unaffected trees can prepare their defenses in advance of an invasion.

What’s more, the mycorrhizal fungi can facilitate nutrient sharing between trees and plants of different species. Dr. Suzanne Simard traced the flow of radioactive carbon 14 from birch to Douglas-fir trees. After only an hour, she found evidence that birches had incorporated the carbon 14 into sugars during photosynthesis, and then shared it with nearby firs (which had been shaded for the experiment). Later, after leaf-off, she found that the evergreen firs were providing sugars to the twiggy birches.

Why would the fungi benefit from distributing resources to trees in need? Their existence depends on the presence of a mature, stable forest with its humid microclimate and flow of nutrients. Tree diversity is essential, since monocultures are vulnerable to disease and disturbance. Therefore, the fungi may share resources in an effort to maintain diversity in the forest and ensure the long-term stability of the environment they enjoy. A diversity of fungi is also important, since different fungi provide different benefits to their hosts and thrive in different situations.

The Wood Wide Web, with all of its natural connections, is beautiful from many angles. Perhaps our society could do worse than trying to emulate a system that has kept forests thriving on Earth for many millennia.

Special Note: Emily’s book, Natural Connections: Exploring Northwoods Nature through Science and Your Senses is here! Order your copy at http://cablemuseum.org/natural-connections-book/.

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! Our new phenology exhibit: “Nature’s Calendar: Signs of the Seasons” is now open.

The Wood Wide Web

The forest is quiet and still. Overnight, our first snow transformed the woods from a sepia tone landscape to a black and white photo. Looking up, the lacy pattern of twigs embosses a network across the sky. When an icy shard catches me in the eye, I look back down, and am struck by the contrast. At the level of the forest floor, each trunk stands stoically alone, separated from its neighbors by a barren expanse of white.

The reality is quite the opposite. At the level of twigs, trees are separate. To avoid competition for sunlight, they tend to grow away from one another, each seeking their own personal bubble. Occasionally, two trunks or two branches will miscalculate and intersect to squeak in the wind, or groan as scar tissue melds them together until death do they part. The real connections, though, happen beneath the duff—almost beneath our notice.

Unlike the twigs, who studiously pretend to ignore each other unless forced to mingle, the miles of roots intersect regularly underground in their search for water and nutrients. When roots of the same or closely related species meet under the right conditions, they fuse together. This grafting requires that tree roots be sufficiently large; be in prolonged contact with each other under pressure that crushes their “skin”; and have sufficient moisture. Once the subterranean stars align, the grafted roots can transfer sugars, water, minerals, and chemical signals from tree to tree.

According to German forester Peter Wohlleben, in his book The Hidden Life of Trees, “most individual trees of the same species growing in the same stand are connected to each other through their root systems.”

This connectivity creates stability for the forest at many levels. On a physical level, the interwoven tangle of roots provides stability in windstorms. Imagine yourself alone, feet tight together, being pushed. Either you fall over, or your “trunk” splits and you step forward for stability. If you stand with a wide base, or link limbs with friends, you can withstand more force. As trees toss in a gale, their own spreading roots provide a stable base. But it doesn’t stop there. Their roots are connected to their neighbors’ roots, and their collective base is as wide as the entire forest.

That entire forest is important. Together, all the trees create a microclimate: their very own ecosystem that buffers wind, stays cooler in the summer, and holds moisture at multiple levels. This microclimate is so important that it might even be worthwhile for well-located trees—those with ample access to water, nutrients, and sunlight—to redistribute those resources among weaker trees and prolong their lives. The partnership would serve to maintain stand integrity against pests, disease, and disruption of the microclimate. It might also maximize use of resources by allowing all trees to grow at an ideal rate, instead of having a few wealthy trees hoard resources they can’t immediately use while weaker trees slow their growth in response to scarcity.  The network of grafted roots facilitates that sharing.

This cooperative community of the grafted root network might confer several additional benefits on its members. For one, it is mostly trees of the same (or sometimes closely related) species that graft at their roots. This means that when stronger trees help weaker ones, they are still focusing on the survival of their own species. The resulting healthy neighbors may become a source of genetic diversity when pollen flies in spring. In addition, by helping weaker neighbors, the stronger trees maintain an “enemy” they know, and prevent the establishment of an unknown competitor who might eventually reduce their access to sunlight or water.

Finally, when a tree dies, its roots can persist and continue contributing to the community. This is no small inheritance in a tree’s constant search for resources. Although the orphaned roots can’t deliver sugars from their own crown anymore, they can bring up nutrients and water in exchange for maintenance by the community. We can see the result of this exchange in the existence of living stumps. Although not every stump will continue to grow, I have occasionally observed new scar tissue forming on the cut surface. This is evidence that, while its crown is gone, the cut tree’s root system is still well-connected and active.

In an even more remarkable example of network support, small redwood, spruce, and balsam fir trees can be albino. Their needles are ghostly pale, and contain no chlorophyll. All their sugar, then, must come from other trees, intravenously fed through their roots.

This period between Thanksgiving and the New Year—when we open our checkbooks to share resources with those in our community who have less, and donate to organizations that we feel will support our favored microclimate—has many parallels to the forest. While we may sometimes feel like stoic individuals, an interwoven community is hidden just out of sight.

Special Note: Emily’s book, Natural Connections: Exploring Northwoods Nature through Science and Your Senses is here! Order your copy at http://cablemuseum.org/natural-connections-book/.

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! Our new phenology exhibit: “Nature’s Calendar: Signs of the Seasons” is now open.

Not Mosquitoes!

One evening a few weeks ago, I looked up from my computer to see a thick swarm of mosquitoes at my window. Hundreds, maybe thousands, of the tiny, leggy, little buggers bounced against the screen in the lamplight. More swarms greeted me in the morning, as they knocked against the windows and formed a gauntlet to my car. Several carpooled to work with me. Others joined me while brushing me teeth the next evening.

The bugs were everywhere. But none had landed on me, or tried to bite, or even buzzed in my ear. That’s not typical mosquito behavior! So, in the spirit of science, I caught one out of midair and gently squashed it. Even a hand lens couldn’t tell me much about this tiny tangle of legs, but after a photo shoot with my macro setting, I was able to ascertain this critter’s innocence: it was definitely not a mosquito.

The spines on its knees were my first clue. The lower joint of each leg had at least one and sometimes multiple little pointy prongs sticking out of it. The two tiny wings were clear and delicately veined. The abdomen was narrow and dark, with a lighter tip. And, most oddly, a projection on the underside of its thorax, what we’d think of as our chest, almost looked like a pale-colored mite clinging like a monkey on his mom.

Stumped, I sent my photo around—first to one entomologist friend, then another. When between the two of them I came up with the family Mycetophilidae and the common name “fungus gnat,” I sent the photo to “my mushroom guy” and he confirmed “Definitely Mycetophilidae. Huge family over a thousand spp. Google glow worms…”

Mycetophilids are in the order Diptera with mosquitoes, gnats, and other two-winged flies.  As I parsed the Wikipedia article, everything began to make sense. They are described as having a “strongly humped thorax and well-developed coxae.” Did you know that an insect’s coxa is the base of its leg, roughly equivalent to our upper thigh? Neither did I. But the humped back and large, pale-colored coxae on my insect are what had looked like a monkey-baby mite to my unaided eye. Fungus gnats are also said to have spinose legs, which must be the scientific way to describe bayonets sticking out of your knees.

I was a little disappointed that none of my entomologist friends could identify my little guy to species. As it turns out, this would require close study of wing venation (ok, that’s not too hard) and chaetotaxy (which means the arrangement of the bristles on their body), and genitalia (which strikes me as a little too invasive for such a recent acquaintance.) Plus, with over 3,000 species in Mycetophilidae, it might take weeks to get through a dichotomous key.

“Most of their natural history secrets remain untold.” wrote Peter H. Kerr in his entry on fungus gnats for the Springer.com Encyclopedia of Entomology. That may be so, but we know more than nothing. For instance, fungus gnats occur on all continents except Antarctica. Most (but not all) types of fungus gnats feast on the fruiting bodies, mycelia, and spores of fungi. They prefer damp habitats where their favorite fungi grow, and sometimes form thick swarms. In those forests, they play an important role in the food web.

A few species of fungus gnats become pests in the damp soil of gardens, farms, nurseries, and overwatered flower pots. Most of the time, though, a female fly will lay her eggs—up to 1,000 in her week-long life—in the cap of a freshly sprouted mushroom. The larvae develop quickly (three weeks from egg to adult) while burrowing into the cap, or make sticky webs on its underside. A few types of larvae are semi-predacious and may eat other insects who visit the mushroom.

Later, I took my mushroom guy’s advice about Googling “glow worms.” Radiant turquoise jewels dripping from cave ceilings appeared in Google Images. As it turns out, in a related family of fungus gnats, about a dozen species have developed bioluminescence. They mostly live in sheltered grottos in New Zealand and Australia. There, tiny larvae spin nests out of silk on the ceiling and dangle dozens of threads of silk beaded with droplets of mucus. Breathless, calm habitats are necessary so that their lines don’t get tangled. Breathless, I’m sure, are explorers who find a replica night sky illuminated on the ceiling of a cave.

The gnat larvae’s glow results from luciferin, a chemical compound similar to that used by fireflies. A hungry larva glows brighter than one who has just eaten, and that glow lures midges, mayflies, mosquitoes, and moths to their doom.

A trip to New Zealand may be in order someday, but for now, I’m just happy to know that it wasn’t a pack of mosquitoes still trying to invade my house in November!

Special Note: Emily’s book, Natural Connections: Exploring Northwoods Nature through Science and Your Senses is here! Order your copy at http://cablemuseum.org/natural-connections-book/.

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! Our new phenology exhibit: “Nature’s Calendar: Signs of the Seasons” is now open.

Driving Back in Time

Everything along the highway south of Duluth was a dismal November gray when I started out on a road trip to visit my favorite cousins; out of touch since the last family wedding two years ago. The skeletons of trees, the low, damp clouds, even the road itself conspired to be gray. A few patches of oaks held their coppery leaves, but they were subdued without the sun. As I sped south, though, I felt like time was moving backward. The fall phenology of color change and leaf-off that I’ve been observing at home unfolded in reverse beside my humming wheels.

First, golden triangles jumped back onto the twigs of a few aspens and clung there fluttering the breeze. Next, I started noticing some of the planted trees and shrubs—weeping willows in yards and something burgundy in the fence lines—still dressed in color.

By the time I got to the city of St. Paul, I’d traveled back a few weeks at least, to the time when sumacs blazed not just with red, but with the full rainbow of green, yellow, and orange as well. When did the sumacs turn in Northern Wisconsin? Early October was my best guess, 3 to 4 weeks ago. In town, other trees held their leaves, too. Brown skeletons were still evident in the post-Halloween landscape, too, but they didn’t dominate like up north.

Emerging on the south side of The Cities, I found myself back in a skeleton land. The city must be a little heat island, tricking plants into a longer growing season. The introduced species, especially, tend to stay green longer. Buckthorn, for example, doesn’t even really have fall colors. Its leaves just go from green to dead. I also suspect that even the native species of planted city trees don’t have quite the same genetics as their wild cousins. The timing of fall leaf drop is affected by both nature and nurture; their genes and their local environment.

By the time I’d reached my first destination in Ames, IA, the changes were drastic. Some trees, especially the ashes, were bare. Ashes don’t have any tolerance for cold. Their strategy is to leaf out late in the spring after all chance of frost is gone, and then drop those leaves early in the fall. But the backyard of my family friends sported a highbush cranberry with fully emerald foliage and clusters of scarlet berries. The big, old oaks in their neighborhood had dropped just a fraction of their canopies. And a katydid sang as we chewed the fat. Many other trees that could never grow up north (i.e. redbud and sycamore) also held their foliage. I have nothing to compare with their timing. We walked around a nearby park, and I shed my sweatshirt in favor of a tank top.  Just 300 miles south, and it felt like I was back in early October.

When I headed south again the next day, the sweatshirt never went on. With an hour to kill, I took an early morning walk in a nearby woodland. Chickadees gave their gargle calls in an effort to sort out the dominance hierarchy in their winter flocks (that, at least, was the same). Then a bright flash of color caught my eye. A huge patch of yellow-orange chicken of the woods mushrooms glowed along a fallen log. They were fresh and juicy, still young, and not riddled with beetles. Those same mushrooms peaked just before Labor Day in my woods. Here in central Iowa, their season must be extended by at least two months!

So few trees lined my view on the way through Kansas that I could hardly judge their progress into autumn. Arriving in the town of Atchison, though, (having driven across four of the USDA’s plant hardiness zones) I found maples in full color, other trees still green, mums and impatiens blooming in my cousin’s flower bed, tomatoes still ripening on her vines, and a yellow butterfly dancing around the park. The 79 degree day just about melted me. Not all trees are benefitting from the warm weather, though. A few ashes and maples have lost their leaves in solidarity with their northern cousins.

The chilly mornings and warm sunshine here in Kansas remind me of early September in Northern Wisconsin. They are having a heat wave, the locals tell me, but even so the average temperatures for early November are 15 degrees warmer in Kansas than in Hayward.

A recent article in the New York Times highlighted new research showing that fall color displays may actually lengthen for a while—as warm weather lasts longer into the year—before they eventually collapse with the loss of our most colorful species when they are forced farther north by the changing climate.

Happily, my visit felt like driving back in time in more ways than one. My cousin hasn’t changed a bit…except that the little girl with light brown curls is her daughter instead of her little sister (boy do they look alike!). Our conversations, too, were as easy, winding and distracted as ever, jumping from one thought to the next. There are some things that neither distance nor climate can change.

Special Note: Emily’s book, Natural Connections: Exploring Northwoods Nature through Science and Your Senses is here! Order your copy at http://cablemuseum.org/natural-connections-book/.

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! Our new phenology exhibit: “Nature’s Calendar: Signs of the Seasons” is now open.

Mount Telemark

Piling out of our cars onto the cracked concrete parking area, we all commented on the perfect weather for our hike. Sunshine, a light breeze, and 45 degrees is about as good as it gets in late October up here. This group of curious adults was gathering for a walk titled “Why Wisconsin Forests Look the Way they Do #5,” led by John Kotar, emeritus professor of forest ecology from University of Wisconsin-Madison, who literally wrote the book on natural communities in the Great Lakes region.

Our destination was Mount Telemark—a place with a lot of history. As we hiked up the gravel access road, weathered sheds huddled in the bushes and rusty ski lifts peeked through the trees and overgrown fields. Telemark Lodge was an alpine ski area founded by Tony Wise in 1947, one of the first in the United States. Tony had discovered alpine skiing while stationed in the Bavarian Alps during World War II, and then used a GI Loan to purchase this hill. The resort eventually became a hub of cross-country skiing, and the birthplace of the world-renowned American Birkebeiner ski race. The impressive lodge with its giant fireplace was built in 1972; a Colosseum with four tennis courts added in 1980; and in 1984 it went through the first bankruptcy (of four).

I personally have relatively few memories of Telemark Lodge when it was open, but in the collective memory of our community, our region, and skiers across the country, this place looms large.

At the center of it all is Mount Telemark, a 300-foot-tall “mountain.” Topo maps show a wide, irregular hill; elongated NW to SE and rising above a sea of lumpy terrain. Legend says that the Ojibwe named it Kawabming, meaning “place to look out from.” The view is quite nice. It attracted skiers here in the 1980’s, and it drew us here today. John Kotar himself has a long history of Birkie skiing and Telemark memories. But its history began long before the Ojibwe, Tony Wise, or John Kotar arrived.

Around 10,000 to 14,000 years ago, near the end of the last ice age, this area was buried under a mile or more of glacial ice, and the ice was melting. The retreat of the glacier was a messy affair. Glaciers don’t glide backward, they disintegrate. Chunks of dirty ice broke off and got buried or surrounded by heaps of debris. Sand and gravel filled in every possible hole, crack, and gap in the remaining ice.

Sediment-choked rivers of meltwater coursed along the glacier’s surface and plunged downward through crevasses, or vertical shafts called moulins. By one account, Mount Telemark was created in one of these moulins. First, sediment would have piled up in the hole, and then become a hill when the ice melted away. By Kotar’s account, the sediment may not have filled in such an orderly space, but simply a gap in the ice that was created as the glacier parted around a bedrock lump. In either case, we ended up with a giant hill of glacial remains. In fact, this is the tallest pile of glacial sediment (technically known as a kame) in all of Minnesota and Wisconsin.

The steep-sided landform provided slopes for 10 different ski runs in its heyday—served by six ropes, 3 T-bars, and 3 double chair lifts. In a little twist of irony—on top of a hill once buried by a mile of ice—Tony Wise devised some of the original snowmaking equipment in the Midwest. The first iteration involved using logging sleds to haul snow up from the airport runways and blowing it out over the slopes with a silo loader. The very next year they installed a commercial system that used Larchmont Snow Guns and pipes—still visible along the forest edges—to carry water uphill.

This landform, made of gravel and cobbles, also provides dry, nutrient-poor soil that favors trees like oaks, pines, and birches. The human disturbance of cleared, then abandoned, ski runs also has impacted what grows here. The gently sloping clearing that we hiked up, for instance, sported a thicket of slender birch trees next to the rusted cables of a ski lift. Birches have very low shade tolerance, and took advantage of the sunny, open space to get a head start.

The view from the top was spectacular. Two vibrant, orange maple trees stood out in the sea of evergreen, rich oak-brown, and tamarack gold. We also could see an airport, golf course, roads, distant fire tower, and more remnants of the resort buildings and ski runs. Of the five places we’ve visited with John to learn “Why Wisconsin Forests Look the Way they Do,” this one especially drives home the fact that glaciers and humans have been two of the driving forces shaping nature in the Northwoods.

Special Note: Emily’s book, Natural Connections: Exploring Northwoods Nature through Science and Your Senses is here! Order your copy at http://cablemuseum.org/natural-connections-book/.

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! Our new phenology exhibit: “Nature’s Calendar: Signs of the Seasons” is now open.

Jack Pine

A fleeting sunset flamed through a ragged stand of jack pines across our bay on Lake Two. Patchy clouds provided just substrate enough to catch the color, and the faint breeze barely ruffled their reflection on the lake. Here, on a classic rock knob campsite in the Boundary Waters, we perched above a scene of rugged beauty.

As it turns out, we were also perched on the border of the legendary Pagami Creek Fire. First detected on August 18, 2001, the smoldering burn stayed within a bog for days. When the relative humidity plummeted to 18% and a north wind picked up on August 26, the fire roared to life and swept through the forest’s crown. By November it had burned 93,000 acres, and sent smoke all the way to Russia. To protect the extremely popular, highly visited landscape of Lakes One and Two, the Forest Service completed a “burn out” operation between the fire and those lakes.

Looking at the maps, it’s quite likely that our view was part of the burn out, and our peninsula campsite was somewhat protected by their efforts. The point on the north side of the bay, now glowing with the sun’s last rays, was also spared. Its grove of jack pines are a respectable uniform height. While jack pines always look a little disheveled (like “something the cat dragged in,” joked my friend when helping us learn pine identification), at least these still had needles.

To the south, the skeletons of burned jack pines shimmered on the glassy lake, and the remains of their scraggly crowns scratched the sunset clouds at the same height as their more fortunate neighbors. Both stands probably started their lives after a past crown fire burned through an even older jack pine forest—although, with jack pines, it might be a little harder to tell if the burned or unburned half of the forest is more fortunate.

The unburned forest is getting up there in years, and has attained the average maximum height for jack pines of about 60 feet. Jack pines mature quickly, and maximum cone production begins at about age 20. The canopy shows signs of decay at only 75 years old. And while individual trees will survive up to 200 years (the oldest known jack pine was 243 years old, found in the Boundary Waters!), there isn’t much hope for a second generation of sun-loving jack pine seedlings under the stifling shade of the adults.

The charred skeleton of the forest is actually brimming with life. A thick carpet of 5-year-old jack pine seedlings, with a few aspen and birch mixed in, promises a bright future.

Jack pine is uniquely attuned to fire. Almost every burn that enters a jack pine stand will climb up the dry ladder of dead lower branches and become a stand-killing crown fire that provides seeds with full sunlight and a dose of fertilizing ash for expeditious growth. Flaky bark and resinous needles urge the fire on. In contrast, red and white pines self-prune their lower branches and grow thick, corky bark to prevent fires from crowning. They’re adapted to ground fires, which clear out competition, but allow old trees to thrive.

The key to jack pine’s dependence on fire, though, is its serotinous cones. Rather than referring to the sticky resin that glues the cones shut, serotiny simply means the trait of delayed seed release. Jack pine achieves this with a satisfying series of tricks.

First, the cones are glued tightly shut with resin, and may remain “in storage” on the tree for several decades. During their extended residence, the resin protects against seed predators like crossbills and squirrels, who make short work of the nutritious seeds in the cones of other species. When a fire finally rips through the forest, the resin ignites at a low temperature, and this relatively cool flame (only 112 degrees Fahrenheit!) helps prevent serious damage. The resin is stored in reservoirs within the cone, but only burns after it has traveled down a duct to the tip of the scale and encounters oxygen there, outside the cone.

Inside, corky material on the cone scales provides insulation for the seeds. The temperature gradient created from the outside-in causes the scales to curl back and open the cone like a flower. In fact, as our small campfire—composed mostly of jack pine twigs laden with tightly closed cones—crackled softly against the descending dusk, we watched in delight as the cones slowly “bloomed.”

Just that series of events is amazing enough, but jack pine’s cones go even further in their Rube Goldberg machine of adaptations. Although the cones open while the fire is still hot, the seeds stay safely stuck in the warm, gooey resin instead of dropping into an inferno. Only once the resin cools, shrinks, and cracks, do the seeds drop out—onto fresh, habitable soil.

What’s more, jack pines in fire-dominated areas produce almost entirely cones that open only with fire, while jack pines in the southern part of their range or on islands where fire is less prevalent, are adapted to opening just from the heat of the sun (a good thing, or else they might never open).

Sure, there is beauty in a colorful sunset “flaming” through the forest, but there is also beauty in the dance of fire, seeds, death, and rebirth when those flames are real.

Special Note: Emily’s book, Natural Connections: Exploring Northwoods Nature through Science and Your Senses is here! Order your copy at http://cablemuseum.org/natural-connections-book/.

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! Our new phenology exhibit: “Nature’s Calendar: Signs of the Seasons” is now open.