Wednesday, April 17, 2013

Maple Syrup

The amber-colored liquid glowed warmly from inside the Mason jar. “Isn’t it just beautiful!?” crowed Deb, the proud owner of this jewel-colored liquid, and a brand-new participant in the age-old tradition of tapping maple trees for syrup. We all agreed that it was lovely, and licked our spoons quite thoroughly after the taste test.

Maple sap carries sugars, water, and other nutrients up from the tree trunk and roots where it was stored for the winter and into the twigs and buds where it can be used to fuel new growth in the spring. Since sap only runs profusely when temperatures fluctuate between warm, sunny days and below freezing nights, and before the leaves emerge, sugaring season is relatively brief. To me, it is impressive that humans figured out how to tap into this wonderful resource, and that the practice continues on both small and industrial scales today.

Humans aren’t the only creatures who know the secrets of the maple tree. An Iroquois legend explains that Native Americans initially learned how to collect sap from maple trees by watching red squirrels cutting into tree bark with their teeth and later returning to lick the sap. Acclaimed naturalist, Bernd Heinrich, author of Winter World and Summer World (two of my favorite books) was the first to describe this behavior for science.

Heinrich watched as red squirrels near his cabin in Maine used their teeth to make a “single pair of chisel-like grooves that punctured the tree to the sap-bearing xylem.” Most impressive to me is that the squirrels didn’t try to drink the dilute sap immediately. Instead, they gave the water in the sap some time to evaporate, and came back early the next morning before the sap started running again, to lick up the more concentrated syrup.

Not only do red squirrels have their own evaporating method, they also choose very carefully when to tap the trees. Squirrels know that anytime the leaves are off and the temperatures are fluctuating, sap will flow. They are able to tap the trees when the conditions are right in the fall and winter, as well as early spring!

Yellow-bellied sapsuckers are woodpeckers who also tap maple trees in the early spring. During this spring syruping season, they only need to make a narrow, circular hole in the bark to get the sugar they crave.

During the summer months, sap doesn’t flow through the xylem in the same way, but sugar manufactured in the leaves is being transported through the phloem. Phloem sap may contain 20-30% sugar – far higher than the 2-3% sugar in xylem sap. Smart as they are, it doesn’t seem like squirrels have figured that out.

Sapsuckers are the experts in summer sap tapping. They drill shallow, quarter-inch, rectangular sap wells in a variety of tree species, and use their brush-like tongues to lap up the sap that accumulates. Once the tree scars over the hole and the flow subsides, the birds drill another row of holes above the first. I’ve read that the pattern of holes sapsuckers use actually forces more sap through their newest holes as some vessels are constricted and sap flow is diverted. Sugar isn’t their only goal. Sapsuckers also eat the inner bark as they chisel, and nab insects that are attracted to the sugar.

Sapsuckers are one of our earliest returning migrants, but only about three weeks behind them come male hummingbirds intent on setting up a nesting territory. (According to the Journey North migration tracking website,, hummingbirds are stalled out in Illinois right now, and sapsuckers have been sighted in southern Wisconsin.) Not many flowers will be blooming by the time the hummingbirds get here, so the tiny birds take advantage of the nectar-like sap from sapsucker wells. In return, they chase off some of the 30-plus other species of birds that may steal the sap.

The sap from sapsucker wells also nourishes a host of other animals, including squirrels, bats, porcupines, and insects from at least 20 different families, such as bees, wasps, hornets, and moths. Snow fleas, who look like flakes of black pepper on the snow, sometimes become pests in sap buckets.

The Journey North website emphasizes just how important sapsuckers are to our northern forest communities. “Studies show that the diversity of many forest species, as well as the size of the population of each species, is greater in areas with high levels of sapsucker activity. Because of this effect, sapsuckers are considered a keystone species – they have a critical impact on the surrounding ecological community that goes beyond what would normally be expected from their numbers.”

The amber-colored maple syrup in the Mason jar must be special. It not only has the ability to connect Deb with her friends, her woods, and an ancient tradition, but it also connects dozens of species in fascinating and important relationships that make our community stronger. And it tastes great on pancakes!

Saturday, April 6, 2013

The Breeze of Balance

A fresh breeze sighs loudly through the tops of the pine trees and gently stirs the air on the forest floor…A warm breath of spring, tiptoeing in from the south, brings the scent of warm soil and wet leaves…A gale from the north swoops over my shoulder and sends ripples racing across the sparkling surface of Lake Superior.
The month of March is known for being windy, and in this year of the slow spring, April is continuing to be just as blustery. Sometimes it wears on me – the constant battle, the whipping hair, and the unceasing noise – but some days it is invigorating and refreshing. What do you love or hate about the wind?
In some Native American and other cultures, wind is a symbol of unity, freedom, eternity and balance. It is as true ecologically as it is metaphorically.
The first time I encountered wind as a symbol of unity, I was on the south shore of Lake Superior, at a wedding on a piney point. A stiff breeze whipped through the trees and blew out the unity candle. With great aplomb, the minister launched into a beautiful and extemporaneous sermon on the wind as a symbol of unity. As the air swirled around all the guests and the happy couple, we imagined how all of our breaths came from and returned to the one body of air that surrounds us and the entire globe.
In some cultures, wind seems to be personified a divine messenger who is able to manipulate unseen energy. Indeed, wind is the main way that our Earth attempts to equal out differences in temperature. Energy from the Sun warms the Earth and the air above it, but it does not heat everything evenly. Some objects heat up more easily than others, and some areas of the Earth receive more energy from the Sun. As warm air rises, cool air flows in to replace it.
The stronger the difference in temperature, the stronger the winds. Think of it this way: in the summer time, the temperature difference between northern Wisconsin and southern Florida is not that big. In the winter, however, that temperature difference can get quite large. In order for our atmosphere to remain in equilibrium, the winds must speed up. Wind is the Earth’s attempt to find a temperature balance.
Wind disperses more than just heat. When strong winds carry away soil, microbes in the soil can act like hitchhikers and go along for the ride. Nutrients and organisms lost from one region may be deposited across the globe. The organisms may colonize otherwise inaccessible regions. The nutrients being blown around the globe may help forested areas obtain trace amounts of minerals. Some organisms in particular get a significant amount of nutrients from dust on the wind. Lichens and epiphytes (“air plants”) are two examples.
Insects also use the wind for long-distance travel. Just how high can they fly? Researchers calculated that “on any given day, the air column rising 50-15,000 feet above one square mile of Louisiana countryside contained an average of 25 million insects.” (From my current bedside book, Insectopedia by Hugh Raffles) At the upper limit, 15,000 feet, there was a ballooning spider who used his silk as a kite. Butterflies, dragonflies, gnats, water striders, leaf bugs, booklice, and katydids have been sighted hundreds of miles out on the open ocean, and aphids have been found on ice floes. Some wingless insects (and plankton!) are plucked from their earthly tethers by a sharp gust of wind, but very few are completely passive travelers.
Wind also helps lakes balance their nutrients and chemicals throughout various layers during fall and spring turnover. In the fall, when the surface water cools to about the same temperature as the lower water, the wind can turbulently mix the water masses together (fall turnover) and even out the temperature and oxygen levels. A similar process occurs during spring after ice-out, as colder surface waters warm to the temperature of bottom waters and the lake mixes (spring turnover). Water from the lake bottom brings nutrients up with it.
I contemplated all those things and more while hiking under the sighing pines. Have you also enjoyed the peaceful atmosphere in a pine grove? We participate in an ancient tradition.  Liu Chi (1311-1375), an important scholar under the Yuan and the Ming Dynasties, wrote “…nothing is better suited to wind than the pine...when wind passes through it, it is neither obstructed nor agitated. Wind flows through smoothly with a natural sound. Listening to it can relieve anxiety and humiliation, wash away confusion and impurity, expand the spirit and lighten the heart, make one feel peaceful and contemplative, cause one to wander free and easy through the skies and travel along with the force of Creation.”
With every breath, we invite the universe in. As the spring winds swirl around you, take a peaceful and contemplative moment to appreciate the wind’s role in encouraging balance and unity in our sometimes stormy world.