Wednesday, February 22, 2017

Fetching the Year About

A single Red maple (Acer rubrum) from April to March.

April 1856  As I was measuring along the Marlborough road, a fine little slate-blue butterfly fluttered over the chain.  Even its feeble strength was required to fetch the year about.   --Journal  Henry David Thoreau

August 1853  I think that within the week I have heard the alder cricket,--a clearer and shriller sound from the leaves in low grounds, a clear shrilling out of a cool moist shade, an autumnal sound.  The year is in the grasp of the crickets, and they are hurling it round swiftly on its axle.  --Journal  Henry David Thoreau

Henry David Thoreau lived nearly all his life in Concord, Massachusetts.  Nearly every day, he spent hours wandering its beloved woods, fields and streams.   Besides studying the behavior of birds, turtles, and other animals, Thoreau recorded detailed observations of seasonal change over many years.1  These he gradually compiled into a nature calendar. Thoreau believed he could find an essential difference--a distinctive essence--to each day of the year, and that, in creating his calendar, he was doing his part to "fetch the year about."  It was almost as if he, like the butterfly or the cricket, were propelling the earth in its march around the year.

I feel this ambition, but confine myself mainly to observing trees I encounter in my walks.2  In this I have at least two advantages over Thoreau: a pocket camera, and the accumulation of a century-and-a-half of evolutionary thought.3  I aim to know the approximate dates and the order in which my trees flower, leaf out, drop their seeds, etc. and also the varied "habits" of these different species.  I hope to observe for enough years to get a rough idea of the year-to-year variation in these seasonal changes.  Someday I might earn the right to say, "I have traveled a good deal" in Brockton."4  Already I have almost enough observations, I think, that I might be tempted--in the doldrums of early spring, say--to open my calendar a bit early, get a good grip on the universe, and try to "fetch the year about" for myself.

 The growing season begins with just a few trees (above: red, Norway, sugar and silver maples down the left margin; below: quaking aspen, river birch and alder) in mid- to late April.  (January to April across the top of the pages.  Yellow shows timing and duration of flowering, green is leaf expansion.)

 May-August. By mid-May the party has really gotten going.
Yellow is flowering, green is leaf expansion, red is fruit/seed dispersal.
The vertical bars at the bottom of the page above are precipitation.

Postscript: I intended to post this in the doldrums of late winter or early spring a year ago--a time of year when little appears to be happening in the natural world.  Instead, I was surprised to find silver maples and quaking aspen beginning to flower, and that news displaced my intended post.  (Freezing weather later on doomed these blooms.)  After this year's unusually warm February, history looks like repeating itself: the fuzzy, pussy-willow-like inner buds of quaking aspen are showing, and silver maples appear on the point of flowering.  Since freezing weather is surely still ahead, this is unfortunate; I hope it's just a coincidence to have such warm weather in mid-winter two years running.

1 His observations were detailed and thorough enough to be used by modern researchers studying the effects climate change has had on different species of plants.

2 Though I couldn't help but notice the high-pitched chittering and aerobatics of the newly-arrived chimney swifts last May 11th!

3 Thoreau read Darwin's Origin of Species shortly after it was published in 1859, and was intrigued enough to begin experiments of his own.

4"I have traveled a good deal in Concord..."  -- Walden

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