Category Archives: Uncategorized

Trees, ecological memory, and seasonal rituals

CaptureDear Friends,

As the solstice approaches, I write with a few short updates.

Holiday trees and gratitude in The New York Times:
Fir trees, olive oil, yule logs: the aromas of holiday traditions evoke deep memories. I write about the ecological meanings of these experiences today in an op-ed.
Recommended reading short-list for the winter:
The following essays and books are, I think, important and beautiful. Well worth your time:

Two essays by David Abram in the amazing new Emergence Magazine. Magic and the machine and Creaturely migrations on a breathing planet.

To Those Who Were Our First Gods, a new chapbook by poet Nickole Brown.

Lauret Savoy‘s Trace: Memory, History, Race, and the American Landscape.

Michael McCarthy‘s The Moth Snowstorm: Nature and Joy.

Reader, Come Home. The Fate of the Reading Brain in a Digital World by Maryanne Wolf.

The Songs of Trees and The Forest Unseen are both available in paperback:

In local, independent bookstores. Find one at IndieBound
Also: AmazonBarnes and NobleBooks-A-Million, iBooks

Many thanks! I send my best wishes for the solstice season.

David

An elder: Rocky Mountain bristlecone pine (Pinus aristata)

Elevation 12000 feet, on what the current human occupants call Mount Goliath. The oldest known tree in Colorado germinated in the 4th century BCE. Youngsters in many stands are from the 1600s AD.

Do these trees live “a long time”? Perhaps this is the wrong thought. They live not such much a long time, but in a different time. Every creature has its rhythm. For life, time is not one thing, its passage is context-dependent. For the bristlecone pine, a needle ticks its clock on a scale of fifteen cycles of summer sun and water. A sapling builds its woody core through one hundred springs. The trees call us out of our own time scale, drawing the imagination into a tempo incommensurate with our own.

A dusky flycatcher sings from the tree top, the details of the cadences of its song ungraspable by my nerves. But the bird’s nerves live in a different geometry and velocity than mine. Another time. For a bird, and more so for a microbial cell, we are the bristlecones, ancient reminders of a mostly forgotten history.  At any one place in the world: thousands, perhaps millions, of times coexist.

Under the pine roots: Precambrian rocks. Ten billion new moons, a billion winters, a quadrillion cellular divisons.

The pines:

 

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(last photo: rings from fallen tree sliced open in visitor center)

 

2018 John Burroughs Medal: The Songs of Trees

The Songs of Trees has been awarded the 2018 John Burroughs Medal for distinguished natural history writing. I’m honored that the book has been recognized in this way and feel very humbled to have the book listed among the list of awardees.

The book was also selected as Best Science Books of 2017 by NPR Science Friday and Favorite Science Books of 2017 by Brain Pickings.

I’m so grateful for the support of my readers. It is an honor and delight to be able to share these stories of the interconnections among trees and people.

Thank you.

And now, back to the woods where the first bloodroots are pushing into the rain-drenched litter.

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The bolt of natural selection

Oberon:

“Yet mark’d I where the bolt of Cupid fell:
It fell upon a little western flower,
Before milk-white, now purple with love’s wound”


Hepatica unfurls its advertisements in both white and purple. This is true of North American species and those in Asia. Why the variation? Natural selection or genetic drift eliminates variation in a population unless some force keeps these purgative pressures at bay. In the case of Hepatica, the costs and benefits of white and purple flowers have not been measured in the wild (readers, correct me if I’m wrong here, please!).  Midwestern populations are more purple than their eastern cousins.

Could pollinators or the light environment be creating different selection pressures? Many populations contain a mix of colors (white is the most common here in Sewanee, but purples are scattered among them in significant numbers), so selection does not seem to favor just one color in each location.

In spring beauty flowers (Claytonia), flowers come in red, white, and intermediate. Natural selection acts on flower color in this species complex ways. Redder flowers are more attractive to pollinators, but whiter flowers have more flavonols, chemicals that act as herbivore deterrents. So, white flowers receive fewer pollinators but red flowers get more damage from slugs. Damage from herbivory changes from year to year and from place to place. So two opposing forces — pollination and herbivory — vary in space and time, resulting in a mix of flower colors. Perhaps a similar turbulent, Puckish convergence of forces also acts on Hepatica?