Trees That Chase Glaciers

Billowing white clouds contrasting with the back drop of cold blue skies move rapidly in an eastward direction like puffs of white condensation pluming out of an old steam locomotive.  The ground has the remnants of a storm that dropped 12 inches of snow just last week.  This snow has been reduced greatly by a fast January thaw that was followed by another cold snap which left behind a frozen white crust that crunches with each step I take in this hardwood forest.  I am still moving slowly from a bad back injury suffered in November, but the call of the wild has me hobbling up this steep north facing hill that is part of 20,000 acres of woods that we refer to as our back yard.  I have it in my mind to visit a stand of birches that are only a half mile from our homestead.  These white birches are completely mature; so mature, in fact, that some are starting to fall under their own weight and the burden of time.

Some may think it odd that I find both friendship and solace in the forest.  Although it is purely imaginary I think that I can understand the language of trees.  They speak not in words but communicate with pheromones and chemicals and God knows what else.  Scientific research shows that when an individual willow is invaded by a pest the entire group of trees in the same area develops a chemical that gives all of the leaves on each tree a bitter taste.  Similarly, red oaks will produce peak crops of acorns simultaneously over large geographic areas to overload the acorn predators so that some acorns may germinate for future generations of this magnificent tree.  It’s not that I can speak with the trees.  It’s simply that after years of being an ecologist I can “read” the forest.  But I must say, and I say this without reservation, that trees seem to have a particular king of intelligence that we humans do not understand.

As I approach this small stand of white birch I notice that they are difficult to see.  The white bark mottled with black patches blends in perfectly with the patchy snow that spreads across this wooded landscape.  The trees are perhaps 70 feet tall and they sway to and fro in the gentle breeze.  It is a mixed stand that includes some black birch, a few red maples, and one butternut tree.  All of the trees are about the same age of about 80 to 90 years old.  The largest of the white birch is about twenty inches in diameter.  This unusually large specimen does not have a branch along its long straight trunk until the first one appears at about thirty feet off the ground.  The tree is old enough that the bark is beginning to stretch and crack in a corkscrew pattern that spirals its way up the tree.  These trees are a sight to behold.   They are testaments to generations of survival.  They are part of the mosaic that makes the forest complete.

The white birch is generally a northern species.  This tree is found from New England to the edge of the Canadian tundra, but some remnant populations can be found south of the formerly glaciated United States at high elevations in places such as the Appalachian Mountains.  All of the millions of white birch that are found north of these locations are related to these relic clusters of birches.  The last glacier era, known as the Wisconsin glacier, built an ice shield that covered tens of thousands of square miles, most of the area in Canada.  The ice shield stopped advancing about fourteen thousand years ago.  The southern most glaciated areas were in New England and New York in the east, and into Illinois, Indiana, and Ohio in the mid-west.  This ice shield was continuous to the polar region to the north and in some areas the ice was two miles thick.  The ice shield devastated all living things, removed all top soil, broke off the tops of mountains, and rerouted river beds.  As the climate warmed and the glaciers retreated plants that survived outside of the glaciated area began to recolonize the landscape.  The recolonization was greatly hastened by cold weather plants that were native to higher elevations in southern climates.  The change from glaciated moonscape to a living plantscape took thousands of years; a mere trifle in geologic time and a miraculous recovery by any standard.

The white birch is a colonial species meaning it grows best in disturbed settings with maximum available sunlight.  This made it the perfect hardwood species to be amongst the first to find its way north as the glaciers melted back to the far north where forests are not present and evidently not welcome.  The white birch is a monoecious which means the tree contains both female and male parts for reproduction.  The white birch seed has tiny wings on it’s fringes that help it to blow in the wind and move good distances to fertile ground.  White birch seedlings require full sunlight and therefore are not a god understory plant and seldom found in mature forests.  The movement of their seed to open sunlit areas is critical to success.  Pine siskins, redpolls, grossbeaks, and ruffed grouse all consume the white birch seed and aid in its distribution as well.  Inch by inch, yard by yard, mile by mile the white birch moved north over thousands of years to the edge of present day tundra where permafrost prevents successful seed germination.  By any account this was an awesome journey.  And who says plants are not as mobile as animals?

As I stand next to this twenty inch diameter white birch I am amazed in the truest sense of the word! This tree is actually a descendant of a relic white birch happened to grow just outside of the glaciated northeast.  I wonder about the exact location of this birch’s long lost ancestor and conclude that it must hail from higher elevations of the Appalachian mountain chain, perhaps as far south as West Virginia.  The twisted part of my imagination wonders if this tree, being of southern extraction, speaks to its birch neighbors in a pheromonal drawl; doubtful, but at least worth a silent laugh.

The white birch was an integral part of my Abenaki ancestor’s daily life.  The bark of the white birch makes it unique amongst hard wood trees.  The bark is thick and comprised of layers.  The inner bark is stiff; similar to wet cowhide that has dried.  The inner layer contains oils and resins that make it completely water proof and gives complete protection from the elements. The outer part of the bark is papery thin.  It shreds away from the inner bark where one end hangs from the trunk of the tree as it flitters in the wind making quiet little noises that add a quiet buzz to the forest.  It is this unusual bark that was an important part of the Algonquian culture.  The oily bark will burn even when completely wet and was used for starting fires in the worse conditions.  Snow, sleet, or rain could not dampen a fire lit by white birch bark.  Buckets for carrying water and catching sap were fashioned out of birch bark.  Wigwams used birch bark as a covering to shelter the Native Americans from the elements. Perhaps the best known white birch bark commodity was the birch bark canoe.  The Abenaki removed the bark off mature white birch trees in one continuous piece.  They then fastened the bark, inner bark on the outside of the canoe, to frames made from spruce and white ash.  The seams were covered with spruce resin the made the water craft leak proof and seaworthy.  A good birch bark canoe seldom took on water and lasted for years.  The Algonquian Nation used them as a trading commodity and these canoes  fetched a handsome reward.

A lesser know commodity of the white birch, and other birch trees as well, is birch syrup.  Like the better known sugar maple sap is collected from the tree in the spring when the sap just starts to sun.  Birch syrup is much more difficult to make than syrup from maples.  Sugar maple sap has a ratio of about forty parts water to one part sugar.  Birch sap has ration of about one hundred to one.  Prior to the use of reverse osmosis to remove water from the sap the successful batch of birch syrup was dependent on a slow boil and human patience.  It must be noted, and you can ask those from Minnesota and Alaska where birch syrup is made, there is nothing quite so quietly delicious as birch syrup.  It is sweet, it is subtle, and yet it still maintains the character of the forest from which it finds its strengths.

The white birch tree is in its glory in the short northern summers.  It grows beautifully shaped deltoid leaves.  Some say each leaf looks like a miniature heart.  Years ago I had a girlfriend who called white birch “love birch” for the shape of the leaves.  In open areas where trees do not have to compete for sunlight the white birch can grow long weeping branches that can sweep the tops of the grasses and herbs the grace this good earth.  These branches create arches of cover where animals can shade themselves from the hot sun or seek shelter during a sudden summer thunder storm.  The white birch has branches that are heavily foliated and these limbs blows readily in a strong breeze.  They dance to the rhythm of the wind, swaying in beat to each gust. Like other birches the seeds are cast off in late fall, and sometimes after the snow falls.  Birch seeds form dense colonies of debris as they blow across frozen snow; a perfect travel mechanism for a tranquil member of the forest community.

The light to the south is getting low.  I grab a thin piece of old birch bark that was deposited on the cold forest floor.  I will carry it back with me through this frozen wonderland.  When I get home I will pop a log onto the fire and write a love note to my wife on the white birch bark as I warm myself by the woodstove that heats our house.

Post Script:

Evidently our female bloodhound “Adia” was jealous of my love letter to my wife.  When Maureen came home she hound Adia eating a piece of birch bark on our living room rug.  She swept up the mess and put it in the wood stove.  I later told her that there was a love note on it and she sent it up in smoke!  We both had a good laugh.  Adia is none the worse for the wear, although still a little jealous.

Written for www.wildramblings in January of 2011.

  • zoologirl

    What a great essay! Birches are some of my favorite trees. I’ve never tried birch syrup, I’ll have to see if I can find (or make) some. Love the post script :)

  • Teresa Evangeline

    I don’t know where to begin to tell you how much I like this post. I, also, love the synchronicities life seems to show us. I was thinking while on my way out west a few days ago, about my friend, JB, and how he made birch syrup tapping trees on his own acreage, back when he was homesteading in Minnesota, before he moved to Moab. I have long felt a deep kinship with trees and felt as though I could communicate with them, or at least listen to them. And the love note to your wife written on birch and the dog’s response – a perfect postscript. This is such a fine post, in every way.

  • bill

    Thanks to both of you for your nice comments. The post script was a true post script, after I posted the story Adia ate the note to my wife, and after we laughed about it I decided it was just another ending for the story and added it at that time.

  • Vagabonde

    I really enjoyed reading this post. I have never tasted birch syrup – but then I had never tasted maple syrup until I came to this country. I love trees. I need a bumper sticker to place on my car saying “will stop for trees” because I do. As I drive if I see a tree I like, I’ll stop the car and go back and take its picture so I will remember it. I spent my teenager years in a suburb of Paris near a large forest and would walk very often in the forest with my dog. It was like a refuge. We have many trees in our yard, but they are all the tall Georgia pine variety.

  • bill

    Birch syrup is unique to the northern most states. It is a small industry in Alaska. The only birch syrup I have ever tasted was in Minnesota. It is unique, rich and sweet, and most often the labor of love. You and I share a love of trees.

  • Montucky

    I enjoyed your post very much! I certainly share your love for trees! We do have birch here, I think it is paper birch, but in this particular area of western Montana there is not a lot of it. I spend a lot of time in the forests and enjoy the old growth forests the most, back in the roadless areas. I believe that there is indeed an understanding of trees that develops after spending a long time among them, observing their growth and the places they choose to make their homes and most of all just appreciating them. I am always in awe of living beings, some of which may be as much as ten times my age.

  • dreamfalcon

    This is a beautiful post. I like the part about the bark and the syrup of course (I will have to taste it one day).
    I would also like to invite you to join the Tree Year project:

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  • Barbara

    Bill I’m sorry to learn you are still having trouble with that injury and hope you get better quickly. Certainly your hike up the mountainside to visit your birches must have done you good in many ways… what a beautiful story. Your love of the forest and its ecology shines through every word.

    Thanks for all that information about birches. Since I was a child I’ve noticed birches as I’ve moved north from the city on day trips or summer vacations – they stand out so, no matter what the season. On an adventure across Canada is was fascinating to see the few old growth stands that still exist along the northern highways… but popular wood doesn’t last long anymore if it’s easy to fell and sell – such a shame.

    Trees do have a language of their own. One of my favourite things to do is stand or sit with my back against a tree and just wait, feel and listen… I come away so much at peace. And I always say good morning to the trees as I walk around my property – I think on my tiny two acres there are more than 25 varieties.

    Looking forward to your next post… and thank you again for this wonderful one.

  • Mike B.

    I hadn’t ever thought about the “recolonization” as the glaciers retreated north. Fascinating stuff.

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  • Pvsutera

    Great entry on the White birch.   You also mentioned the solitary Butternut briefly in your writing.
    While we rarely see Butternut trees these days, they have 2 habitats.  Well-drained river and stream banks, are one, but they also will grow out of very thin soil in rocky areas.   I suggest they  also may been early colonists of the glacier scraped landscape and till.   I have seen them recently growing out of talus slopes where nothing else was growing.   The tree is in trouble now but efforts are being made to aid its recovery.   A study of the butternuts in the north showed they had an extreme lack of genetic diversity – the further north you go, the less diversity.  It rather proves the same point you were making about the northern White birch descending from trees on Appalachian highlands further south.   The butternuts spread north was also aided by the availability of water from glacial melt, and good drainage.   Right now the Butternut Canker has reduced populations of Butternut by up to 80%.  A few trees appear to be resistant although good growing conditions also contribute to resistance.   Hybrids with Japanese walnuts and their descendents are common in the Northeast and are also highly resistant to canker.   Their early colonizer role is also supported by their intolerance to shading from other trees.   Such shading was likely to be less during the immediate post-glacial period.   Look forward to reading more of your writings! 

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