Speaking of Nature: The yellow birch: A golden surprise in the woods
Published: 01-17-2023 3:30 PM |
In keeping with my New Years resolution to focus some more attention on the plants that live around us I decided to look for a list that I was convinced must exist somewhere. You see, I am a compulsive list-maker. The blood of a scientist runs through my veins and as a result I tend to keep track of all sorts of things. I am also a collector (coins, stamps, bird species, etc.) and this listing compulsion extends to those pursuits as well. So, I was absolutely convinced that I had mad a list of tree species that I had covered, when I had covered them and when I should think about covering them again.
Wouldn’t you know … I found it!
Recorded on a small pad of lined paper was an excellent specimen of the lists I make. It was neatly laid out and it had a clear title, but even more important was the fact that I recorded the date on which I had made the list. What was surprising was the age of this particular list, which I had carefully recorded as September 2014. Even more surprising was the age of some of the columns that I had written. As an example, since I last wrote about the American chestnut in May of 2001, I think it is fair game for another visit to this particular species.
The final shock came when I discovered that I had never dedicated an entire column to today’s species, the yellow birch (Betulaalleghaniensis). By the way, kudos are owed to my dendrology professor from my undergraduate days at University of Massachusetts Amherst. I took that class in 1988 and all these years later I remembered the scientific name of the yellow birch perfectly! Anyway, this is a really great tree to talk about in the wintertime because it has such recognizable bark. So buckle up for a wild dive into the life of one of our beautiful native trees.
The bark of most birch trees has a characteristic ”peely” quality, but the yellow birch takes this to a remarkably gorgeous extreme. The layers of outer bark are so numerous and so thin that they curl up into little rolls that have a translucency to them, like shimmering rolls of metallic gold mica. Young yellow birches may not show this particular characteristic too clearly, but older specimens are simply impossible to miss, or to mistake for any other tree. The yellow birch is a golden surprise in the woods.
Of all our native birch species, the yellow birch is the most commercially valuable. The wood is used in a variety of ways, but the most familiar might be as paneling in cabinetry and other furniture. Large logs are set into even larger lathes and as the log is spun a large knife is used to shave off very thin sheets of wood. These sheets are then pressed and dried and then glued to the front of large sheets of composite woods (like plywood, for instance) and give doors and cabinets the appearance of being made from a single piece of wood.
From a wildlife perspective, the trees are perhaps even more valuable. The branches and twigs, which have a distinct and delightful smell and taste of wintergreen, are edible and highly prized by deer and moose. The tiny, winged seeds that are borne in catkins, will disperse in the fall and winter and are often blown across the snow like ground black pepper on a white tablecloth. The earliest age for a tree to start reproducing is about 30 years and the “prime” breeding age is about 70 years.
The small seeds are extremely numerous and can number up to 5 million per acre in a good year. In those rare years of a “bumper crop” the number can soar to 35 million per acre. As you might imagine, there is no way that this many seeds will ever survive to maturity. Most of the seeds find themselves in the wrong place and the young trees perish. In an undisturbed forest the only habitat that really offers the young trees a chance is fallen logs covered with moss. As a result, many yellow birches in mature forests start their lives as “stilt” trees, which have roots that grow around their “nursery logs” and into the ground. Once the logs rot away, it gives the trees the appearance of standing on short, stubby legs.
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The adult trees also provide valuable food for birds like American goldfinches and common redpolls. The small seeds are just the right size for these small seed-eating birds to consume and this can explain their presence in forests during the later part of the fall and early winter. Once the seeds hit the ground they wait until June to germinate and at that point they provide a valuable source of fresh greenery for deer, moose, rabbits, snowshoe hares and any other herbivores in need of food.
Finally, another interesting plant-wildlife connection occurs between the yellow birch and a woodpecker called a yellow-bellied sapsucker. These birds drill rows of small holes in the bark of yellow birches and collect the nutritious sap with specialized tongues that remind me of barbecue saucing brush. The birds may also eat any small insects that are attracted to the sap and they often find themselves in competition with ruby-throated hummingbirds that might zip in and steal a sip here and there.
Winter is a great time to get outside and look for the yellow birch because the trunks of these trees stand out so clearly. Head to any state park or conservation area that offers trails to walk on and you stand a good chance of finding a mature yellow birch standing in the woods. Why not take a friend and make a day of it?
Bill Danielson has been a professional writer and nature photographer for 25 years. He has worked for the National Park Service, the US Forest Service, the Nature Conservancy and the Massachusetts State Parks and he currently teaches high school biology and physics. For more in formation visit his website at www.speakingofnature.com, or head over to Speaking of Nature on Facebook.
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