Nature Notes – From the Backyard to the Biosphere. Bravo to the Birch

Thank goodness that canoe season has arrived once again. Getting back out on the water, feeling the dip and swing of the paddles as they propel this elegant watercraft and its lucky passengers forward, hearing the droplets gently fall and meet the surface of the lake or river — ah, the simple joy of it. What other means of water travel can compare to the ease and gentility of the graceful canoe? Quiet, swift, efficient, miraculously able to get you into (and out of) the tightest spaces — it’s quite an invention.

Of course, one cannot talk about the canoe without hearkening back to the days of its birch-bark ancestors. When thinking of this relative to our modern-day fibreglass, aluminum, and Kevlar friends, we must pause a while to think of the lovely tree that gave rise to the much-admired birch-bark canoe — Betula papyrifera, the paper birch.

B. papyrifera is one heck of a plant. Much more than just a simple beauty, this shining, bright white, artistically envisioned tree has been dubbed by many northern aboriginal groups as the single most useful tree around. It is what you might refer to as multifunctional, lending a hand in areas as diverse as health, technology and nutrition.

Various parts of the tree have traditionally been used to treat a variety of ailments, including skin rashes, sores, and dermal parasites such as ringworm. Its wood, that is harder than that of many of its northern arboreal cousins, is perfect for building boats, sleds, snowshoes and paddles. The bark, ideal for making containers, once formed the basis for everything from the familiar canoe all the way through to cups and cradles for babies. As the icing on the cake, this beauty of a tree produces a sweet sap that can be collected and boiled down to make a maple-syrup type sweet treat.

The paper birch is a star not only from the perspective of use value to people. It is also quite a winner in the ecological sense of things. Cold tolerance is not an issue for the birch as it is a largely northern species. Ranging right across Canada and into the northern states, the paper birch is able to tolerate the presence of ice in its intercellular tissues. Fire? Not a problem. B. papyrifera is ready and willing to sprout new shoots from existing roots or any above-ground parts that managed to survive the burn. Forestry activities left some bare ground? Wind pollination helps this puppy to arrive early on scene, allowing it to capitalize on the high intensity light conditions in which it can grow quickly and, in many cases, form nearly pure stands.

The little dark horizontal bars that grace the bark (the ones you can peek through when you pick up a piece of fallen birch-bark from the ground) help the tree to breathe. These lenticels allow for efficient gas exchange between the inner parts of the tree and its outside environment.

Those hungry herbivores had better not get too greedy, or they’ll be in for it. The paper birch is a smart one, increasing the presence of toxins known as secondary metabolites when the nibbling gets a little too extreme. While some plants maintain static quantities of toxins to deter herbivory over the long term, the paper birch decided somewhere along the way not to waste its energy creating these substances unless it was absolutely necessary. Instead, as herbivory increases in intensity, the level of toxic compounds in the paper birch’s tasty parts rises to turn off even the most devoted birch connoisseur.

So, next time you’re out in the canoe or up north checking out the scenery, don’t be shy to pass on a little salute to this special tree. The paper birch, so deserving of our admiration, might just give a little flirtatious sway in the breeze in response to your thanks in recognition of all that it is.

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