The Paradox of Sugaring

By Laura Yayac

saptap (1)It flavors creemees, cotton candy, and liqueurs. It’s poured over pancakes and snow, and is used in countless recipes. And right now, the raw sap is running from trees into buckets and webs of tubing then onto sugarhouses, where it’s boiled into maple syrup in all its amber glory.

Sap runs when the nights are cold and the days warm, but something about this does not make sense.

Before I get to that, though, a bit of history. European settlers learned about maple sugaring from native tribes, who in turn have a variety of legends as to how they discovered that maple sap could be boiled into a liquid sugar. Written accounts of maple tapping date from the 1550s, and it isn’t just people who love maple syrup. One of the explanations for human discovery of syrup is watching red squirrels (Tamiasciurus hudsonicus). These critters have been documented using their teeth to cut into sugar maples, then returning over the next few days, after much of the water has evaporated, to lick the sweet blobs that are left behind.

Most Vermonters know the story and process of sugaring, but I’ll offer a refresher for those who, like me, did not grow up next to a sugarbush. Sugar maple (Acer saccharum) trees are the type most commonly tapped. Sap flows through the sapwood of the tree, the layer between the bark and the center heartwood. In the fall, trees turn their sugars into starches to store them in their roots and trunk for the winter. In early spring when the days are above freezing the starches are returned to sugars and the sap begins to flow. In a tapped tree, it flows out of the tap, and it is then drawn back up into the tree at night when the freezing temperatures return. Recent innovations such as a one-way valve for tapping, patented by Tim Perkins of the Proctor Research Center, help to keep microorganisms from being pulled back into the tree when this occurs.

But wait. If raw sap is 98% water, shouldn’t it expand when it freezes, and therefore be pushed out of the tree rather than pulled back in at night?

Maples are unusual among tree species in that the cells surrounding their vessels (the sap-carrying veins) are filled with gases instead of liquids. During freezing temperatures, the carbon dioxide (CO2) in these spaces contracts, creating room for the sap to move out of the veins and into the surrounding cells. As the sap does this, more sap is drawn up to replace it. (Other tree species have liquid-filled cells, so during freezing temperatures at night, the liquid-filled cells and the sap freeze. Because the sap has no open cell to move into, and it expands as it freezes, any sap that remains in liquid form is expelled).

When temperatures rise above freezing during the day, a combination of forces propel the sap out of the tree. Expanding CO2 gas bubbles push the frosty sap out of the cells and gravity pulls liquid sap down into the sugarmaker’s tubes. It’s from this harvest that 40 gallons of sap are boiled down to one gallon of maple syrup, and that Vermonters can once again revel in all things maple.

With help from: and

Photo by Bryan Pfeiffer.

Laura Yayac is an Ecological Planning student who uses maple syrup in as many recipes as she can.

Before It’s Gone, A Primer on Snow

Any skier or snowboarder knows that snow does not come in just one form.  Snowpacks are as variable as the snowflakes that form them.  We have all heard the claim that Eskimos have dozens of words for snow (actually, I discovered, just more flexibility in how root words are modified), but what about our terms for snow?  Skiers talk about corduroy and corn snow, but the variation in snow types extends beyond the ski slopes. 

601124_677097335993_631112764_nHere is your late-in-the-season glossary of snow.  Maybe your optimism tells you that the snow won’t be with us much longer, but it might be in your best interest to brush up, just in case.

Snow forms when the atmospheric temperature is at or below freezing.  In certain conditions, it is even possible for snow to reach the ground when the ground temperature is 41 degrees Fahrenheit.  Freezing atmospheric temperatures, combined with moisture in the air, forms snow crystals.  Snow crystals exist in four forms: snowflakes, hoarfrost, graupel, and polycrystals.

  • Snowflakes, which we are all familiar with, are clusters of ice crystals that fall from clouds.  Their shape is dependent on the conditions in which they are formed and through which they fall.
  • Hoarfrost is our name for ice crystals that form on small surfaces that are open to the air.  When a surface’s temperature is lower than the frost point of the surrounding air, moisture transforms directly from vapor to solid, forming delicate laces of surficial ice.
  • Graupel is the round, pellet-like snow that resembles a softer hail.  When ice crystals fall through super-cooled cloud droplets (which remain liquid although they are below freezing temperatures), the droplets freeze to the crystals, forming a clump.
  • Polycrystals are flakes made up of many individual crystals.

The National Snow and Ice Data Center has gone one step further and categorized the types of snow cover, or snowpack.  Snowpack is defined as all the snow and ice that lies on the ground at a given time, including fresh snow and any older snow still on the ground.  Its composition is affected by air and ground temperatures, temperature stability, wind, and the length of time that snow stays on the ground.  The six types of snowpack are: new snow, firn, névé, old snow, perennial snow, and powder snow.

  • New snow is snow that accumulated recently enough that the original form of its ice crystals is still recognizable, as when snowflakes’ delicate shapes are still visible on top of a layer of fresh pow.
  • Firn is snowpack older than one year.  It is dense and well-bonded.
  • Névé is young, granular snow that has been partially melted and then refrozen.  This process hardens and compacts it.  If névé lasts longer than a year, it becomes firn.  This is the main snowpack type resulting in glacier formation.
  • Old snow has been transformed enough that its ice crystals’ original form is not recognizable.  The amount of time new snow takes to become old snow depends on a number of factors.
  • Perennial snow, as its name suggests, is snowpack that never melts but stays on the ground year after year.
  • Powder snow is fresh, dry snow comprised of loose crystals.

Consider this the next time a friend invites you to hit the slopes.  Is it really powder you’re carving or is it old snow?

Don’t even get me started on the different types of snowfall (blizzard, snowstorm, snow flurry, snow squall, snowburst, blowing snow, drifting snow).

Winter Blooms

By Matt Pierle


Cabin fever have you ready to see flowers again? If so, you’ve got options: Brazil and Bali are nice this time of year. Or seek out plants at a world-class botanical conservatory in, say, Montreal, London or San Francisco.

If you’re short on time or prefer shoestring travel though, you could do what I did over spring (technically late winter) break and book a $26 ticket on the Megabus from Burlington to Boston. From South Station Boston walk north to Chinatown, through Boston Common, past the frozen Frog Pond, to the Longfellow Bridge, over the Charles River to Cambridge and kick it up Broadway to Harvard Street. Continue north all the way to the Harvard Museum of Natural History.

In bloom you’ll find the extensive Ware Collection of Glass Models of Plants created by Czech born Leopold Blaschka and his son Rudolf. Most people simply call the collection “The Glass Flowers.” You read that right. This collection is not of flowers under glass, it is of flowers made of glass.

These life-size and larger-than-life specimens are more than impressionistic representations of garden blossoms; they are über-accurate botanical sculptures of a diversity of wild and cultivated plants. The pieces will challenge your powers to believe that something so realistic could be made from inert, colored sand.


Who were the Blaschkas? How did they do it? And how did Harvard acquire these pieces?

The Blaschkas’ craft was not glassblowing. These pieces were created through a process called flameworking or lampworking. Glass rods were heated with the aid of paraffin and alcohol lamps, then cut with specialized scissors and shaped with tweezers, prods and other tools. Fine cooper wire provides structure for some of the daintier botanical structures, although I never once noticed the hidden metal armatures. Originally the pair worked with clear glass and then painted the models. Later they employed colored glass from the get go. Their eye for color was refined, to say the least, and a hundred or so years of display at the museum does not seem to have compromised their luster.

The artists, who worked without assistants or apprentices, came from a strong tradition of glasswork, a trade well established in their native Czech Republic. Indeed, Leopold’s father had also been a glassmaker. After Rudolf’s birth in 1857 Leopold moved the family to Dresden and established a workshop there.

From as early as 1863, Leopold earned a reputation for crafting museum quality glass invertebrates, mostly marine inverts, everything from jellyfish, and mollusks to sponges and corals.  The lifelike pieces were and are held by universities, museums and aquaria the world over – a few of which can also be seen at the Harvard Museum of Comparative Zoology.


Leopold Blaschka experimented with plant models between 1860-1862 prior to making the marine models. These early plant models went from one owner to another before eventually being destroyed in a museum fire in the city of Liege, Belgium. In 1876 Rudolf started working full-time with his father. The Blaschkas spent the next ten years focusing on marine works for until they were approached by Dr. George L. Goodale who asked them them to make a few glass plants for Harvard.

Dr. Goodale was a plant physiologist and then curator of the herbarium at Harvard. After becaming familiar with the Blaschka’s impeccable work he traveled to Europe to meet them. Goodall wanted to have plant models that would endure for teaching and demonstration purposes. The Blaschkas shipped some pieces to the U.S. on speculation. In spite of being damaged in New York by customs inspection, Goodale showed the floral pieces to the Elizabeth Ware and her daughter Mary. The Ware women were sufficiently impressed. They generously offered to fund all aspects of the artistic production of more plants in honor of their late husband and father Dr. Charles Ware, a graduate of Harvard Medical School.

According to Jennifer Brown, the collection manager, Goodale hoped there would be at least 50 pieces created. That was 1886. Over the next 50 years the father-son team produced for Harvard around 4,300 individual pieces representing 787 distinct plant species.

The pair worked from plant specimens and cuttings sent from Harvard, from live material planted around their estate and from botanical drawings. While Leopold Blaschka remained in Europe, Rudolf traveled to the Americas in 1892 and then again in 1895. On those trips, he visited the growing collection of glass flowers at Harvard and did botanical drawings in the U.S. and Jamaica.

Packed in cardboard boxes with tissue paper and excelsior (wood wool), surprisingly few pieces were damaged in transport across the Atlantic from Germany to the U.S.


At Harvard, the glass flowers are displayed in the style of herbarium vouchers

Each plant’s common and Linnaean name is shown on a tag, and smaller tags interpret oversized plant parts along with the degree of magnification (two to several hundred times). In this way, plant structures not easily seen with the naked eye are clearly displayed.

Peer into the throat of an iris to see the fine hairs lining the inner surface of the petals. See how the Nerf-football-sized male flower of a bat-pollinated banana plant dwarfs the dozens of female flowers that will develop one of our most globally important fruits.

Along with floral structures and fruiting bodies and non-reproductive plant parts like roots, leaf buds, and trichomes are presented in all of their fine scale glory.

Because of Harvard faculty interests in economic botany, later productions by the Blaschkas focused on cultivated plants from palms to figs, and from coffee to cacao.

There is even a rotting fruit series that depicts in jaw dropping accuracy stone fruits with fungus damage and apple fruit with cutaneous scab infections. Pieces emphasizing pollination feature flowers lacking one or more petals in order to show in graphic detail how foraging bees facilitating the transfer of male gametes from one plant to another.


Exquisitely lifelike and, even to a botanist’s eye, beyond botanical reproach, the glass flowers will at once delight and educate you

Delicate flowers, tangles of roots and fresh leaves are all created as if by cloning. Goodale’s interest in having a collection of precise teaching specimens has been realized.

While several glass artists have tried, no one has replicating the exacting accuracy that the Blaschkas achieved. It’s not surprising that people arrive to Cambridge from all over the world to see these masterpieces and that many suggest that a divine energy or touch must have guided their creations.

If you’re a lover of plants, sculpture or hyper-realistic art, this is a collection you’ll want to see for yourself. Kids to seasoned botanists alike will appreciate the gallery, and the nice thing is, no matter which month you visit, the glass flowers are guaranteed to be in bloom.

Right now, it could be the perfect cure for cabin fever.




Matt Pierle is a Field Naturalist candidate at the University of Vermont who has botanized from California to Cambridge. 

Special thanks to Collection Manager, Jennifer Brown, Herbarium Co-Director, Dr. Charles Davis and Gallery Volunteer, David Donovan. All photos by Matt Pierle with permission from the Harvard University Herbaria and Harvard Museum of Natural History.







Why our bodies need those blue-sky days

387374_939936702278_1594645291_nThe contrast of fresh powdered snow amplified by a background of cerulean vastness is one of nature’s finest vistas.  Fellow outdoor enthusiasts refer to these conditions as “bluebird” days, a term routinely followed with hooting, hollering, and high-fiving between friends and strangers gathering on the ski hill to worship the good weather.

Why do we have more fun in the sun?  It isn’t the scenery; it’s chemistry.  As living organisms, harvesting energy from the sun is crucial for regulating homeostasis. Our bodies literally crave sunshine, especially in the winter when it’s harder to come by as days are shortened, offsetting our mood as a result.

Serotonin is a neurotransmitter, sending signals from neurons to target cells.  It is one of the oldest components of the nervous system found in the Animal Kingdom, derived over a billion years ago from a line of molecules releasing energy derived from the sun.  In sea urchins, it controls appetite.  In higher order mammals, it regulates sleep patterns. In humans, it functions as an anti-depressant to regulate the brain’s emotional state.

There’s no better cure to mid-winter blues than a bluebird day.  You may not realize it, but these are the days your mood swings back to its peek.  This may be due to the supporting benefits of another familiar product of the sun, Vitamin D.  Vitamin D is produced in the skin in response to UVB rays.  It encourages and stabilizes serotonin production, formulating a natural balance to keep us happy.  A Vitamin D deficiency will not just result in brittle bones, it will cause serotonin levels to dramatically fluctuate (aka “mood swing”).

Low levels of serotonin instigate classic winter habits of seasonal depression, craving comfort food, and repeatedly hitting the snooze button in the morning.  Like many other species, humans respond to circadian rhythms with periods of lightness and darkness. As the day shifts into night, your body stops producing Vitamin D and serotonin levels drop.  This doesn’t mean night equals sadness, but the body definitely reacts by slowing down both physically and mentally.

If you’re indoors, pause for a moment and look up.  Are you now marveling at a glowing fluorescent bulb illuminating the room to what you think is an intense source of light?  You’re actually deprived of slices of the spectrum.  Light bulbs lack UV rays, which are exactly the rays that stimulate Vitamin D production.  In fact, too much time spent bunkered down under fluorescent lighting may actually decrease serotonin, leaving you grumpy and fatigued.

Seasonal affective disorder (SAD) runs rampant during winter months with extended periods of gray, overcast skies to compliment frigid, short days.  If you find yourself routinely depressed, fatigued, and unable to concentrate, perhaps it’s time to ditch the Zoloft and get outside.

Friday Field Walks 2014


Beyond a Collection of Facts

By Clare Crosby


I spent my childhood hosting acorn cap tea parties for fairies, scurrying on calloused feet to collect eggs from the chicken coop, and reenacting Little House on The Prairie in the meadow behind my house, just east of Austin, TX. I did not suffer from “Nature Deficit Disorder.”

But as I grew, my interests shifted. I traded the meadow for well-manicured athletic fields and our old pond for swimming pools. My interest in my Central Texas natural surroundings paused around 8 years old. I never figured out what species of oak provided teacups for my parties, only that the caps were nicely proportioned for fairies. Neither did I learn what type of moss my fairies used for seat cushions, only that it opened into minute stars under sprinkled water.

I’m embarrassed now, as a naturalist, to admit that I don’t know even some of the most common species of my home state. This lack of knowledge, however, offers opportunity when I return to Texas from Vermont, the home of my formal ecological education. As I walk old trails and come across a familiar (yet unknown) tree, my inclination is to turn to field guides or a trusted expert to tell me what to call it, who eats it, and what it might reveal about the soil beneath it. In Vermont, I have had a string of wonderful professors and peers to teach me about the natural world, assisted, of course, by an ever-growing library of field guides. I hope to be so lucky again in Texas.

This time around, however, I am resisting my urge to immediately consult the experts. I am allowing myself to make a few discoveries.

So today I went for a walk not with my field guides, but with a pair of scissors and my mom, who admires nature through eyes much more artistic than my own. We collected a few specimens, returned to our kitchen table, and settled in with our pencils, watercolors, and tea. I chose specimens that were familiar from childhood memories, but not known to me as a naturalist.

I watched my mom lovingly render each thorn on a briar that had caused me many childhood tears. My old hatred melted into fascination, then respect. Inspired, I shifted my focus to the specimens before me.

I found that Texas mountain laurel—whose “hot beans,” my brothers knew, heat up enough when rubbed on rough stone to induce shrieks from little sisters—holds its leaves into late December. The terminal leaflet, at least in the sample I selected, lists to one side. The woody, wrinkled seedpods are difficult to open before their time and the beans within, fire engine red in my memory, can also be nearly black.


As I sketched a species of elm, whose name I do not know, but which grew in the front yard of my childhood home, I noted that the bases of the small leaves are not dramatically asymmetrical like the Vermont species of elm. The delicate twigs of a sapling bend substantially at each minuscule leaf bud. Both the green and yellow leaves are sandpapery. The largest brown patches appeared confined by the leaves’ venation.

Perhaps I could have learned most of this from a book, a class, or a friend. I would have missed some details, though, along with an opportunity for connection.

Often as a naturalist I have learned only the characteristics that will allow me to distinguish one plant from others. This is, of course, useful. However, we protect what we care about and we care more when we have some sense of ownership or a personal connection beyond a collection of facts. So today, with my mom, I wanted to get to know my childhood acquaintances more intimately, moving past the strictly functional. I wanted to find companions for my fairy teacups and warm eggs. While it may not be a skill to add to my resume, I know that this afternoon spent sketching with my mom has made me a more inspired steward of the world around me.

In addition to being a Field Naturalist and Ecological Planning student, Clare Crosby is a connoisseur of board games. 

Natural Sounds

By Joanne Garton

Jellyfish2I remained still underneath a swirling aquatic world. Corals of brilliant blue and pink mixed with fish of bold black and yellow. Water of crystal clarity ebbed and flowed towards gorgeously blond sand. Sea anemone wavered and I watched, transfixed, as the bulging eyes of a massively prehistoric stingray reflected the wonder of it all.

As the sea swelled, forty violins soared to a grandiose peak. As a wave smashed on the rocky shore, cymbals crashed and drums bellowed. And as the wave dissipated, a bassoon emerged from lonesome depths where a barrier shark swam far from the colorful critters near the sun’s dancing rays.

It took three wave and cymbal crashes before I realized that this music of the sea had been choreographed with Hollywood precision. As a tourist in the Georgia Aquarium in Atlanta, I was listening to the soundtrack of nature, piped in through the invisibly scattered speakers that followed my trail and amplified my mood. Those soaring chords and delightful suspensions latched onto my wonder and awe, building my anticipation and enhanced my excitement when the belugas breeched or the sea lions wrestled.

But was this a bad thing? The music kept me focused, adding drama to the already dramatic, while drowning out the hoards of young families that mixed in with my own. Carefully arranged and built to sell, this supposed music of nature sets the mood that inspires us to linger a while, more so than perhaps, these days, silence can.

Of course, real nature is not silent. Winds sweep, critters cluck, wolves howl and woodpeckers tap. So do other animals hear music in nature? What about insects, reptiles, or microbes? What do they hear?

Welcome to the biophony, the organic orchestra that makes up the ambient sound of every habitat. Although humans easily relate to the patterned twirls of songbirds and the rhythmic ballads of humpback whales, the idea that music can be created by the mixed timbres and frequencies of any species is largely foreign. The further supposition that the animals themselves may perceive music out of these sounds is a beautiful yet untestable hypothesis. Unless there exists a test for tranquility, which I’m sure is plausible.

The Tlingit and Inuit have listened for millennia to the soundscape of whales in the ocean through the hulls of their boats. As a landlubber and tourist most unlike these seafaring people, I’ll rely on carefully placed chord suspensions to steer my way through the aquarium and cue my emotions. Regardless of what it sounds like on the other side of the glass, I did find some sort of tranquility gazing at the octopus as it peeled its way across the tank to the rumble of lumbering cellos and distant timpanis. Many days later, as an emotionally wrought symphony played over the radio, my three-year-old son said, “That’s the music from the aquarium.” Whether it was from the real sea or the orchestrated one, I knew that the music had cemented the experience.

With help from: The Music of Nature and the Nature of Music by Gray et. al., in Science, January 5, 2001, and Music without Borders by Susan Milius in Science News, April 15, 2000.

 Joanne Garton is an Ecological Planning student who knows quite a lot about music and very little about sea anemone. 

A “Solst-Ice” Report: The Season’s First “Big Chill”

DSCN7727By Matt Pierle

In the aftermath of a backwoods Solstice party in Lamoille County we awoke to a small mountain of dishes and no electricity. The longest night of the year had wrapped us in an icy bear hug.

Cold rain followed by dropping temps had frozen everything stiff.  Tree trunks, branches, rocks – anything not moving fast enough to dance off the cold crystalline bonds – was treated to an icy exoskeleton.

As more precipitation came, the ice coats thickened. The substrate for later drops to adhere to grew as the ice put on layer after layer. Classic positive feedback.

Next year’s already-formed buds and catkins, shelf fungi, conifer needles, marcescent oak and beech leaves were all locked inside one-quarter to a full inch of ice. The forest and hill farm landscape performed back-to-back versions of John Cage’s 4’33”.

NPR news from a crank-operated radio reported, “hundreds of thousands of homes and businesses without power in Michigan, New York, and the Northeast”– no doubt a result of trees and frozen limbs coming down on overhead transmission lines. Read More

Roasting (and Restoring) Chestnuts

By Kat Deely

320px-American_Chestnut“Chestnuts roasting on an open fire.
Jack Frost nipping at your nose….” 

These words invoke every shiver of childhood anticipation for Christmas morning. Family time, feasting time, vacation time, and of course, presents time. I’ve been hearing these words sung every holiday season since before I can remember, and they have magically dropped me into a snow-globe world. So, it is with a bit of humility that I must admit something. I’ve never roasted chestnuts on an open fire. I’ve never roasted chestnuts on anything. I’ve never eaten a chestnut! And I bet I’m not alone. So how is it, this iconic Christmas classic’s first line is complete balderdash to the holiday seasons we know today? Read More

A Chicken of the Woods

ChickenOfTheWoodsBy Colin Stone Peacock

I am the glistening, blackened, and charred non-stick remains of a foodie. Enameled by years of cooking and eating professionally, I am unphased by the most ample and esoteric culinary ingredients and pathologies.

But the bitter kimchi of my heart sweetened ever so slightly the summer before last, when I met the bright and gleaming orange and yellow folds of Laetiporus sulphureus, commonly known as Chicken of the Woods.

It is one of the most easily identifiable, seasonally available, and tastiest mushrooms I have ever met. The drab and fickle morels of my forefathers will never look the same. Chicken is the flavor I would use to describe them. That, and a citric tanginess I have never encountered in another fungi. Read More