Category Archives: Uncategorized

The bolt of natural selection


“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?

The Songs of Trees, pre-publication comments

The first round of “advance praise” for The Songs of Trees is in. I’m thrilled and humbled that Elizabeth Kolbert, Deborah Blum, Peter Wohlleben, Neil Shea, DJ Spooky, Peter Crane, and Carl Zimmer read the first proofs and shared their thoughts.

“David George Haskell is a wonderful writer and an equally keen observer of the natural world. The Song of Trees is at once lyrical and informative, filled with beauty and also a sense of loss.” Elizabeth Kolbert, Pulitzer Prize-winning author of The Sixth Extinction, staff writer at The New Yorker.

“David George Haskell may be the finest literary nature writer working today. The Songs of Trees – compelling, lyrical, wise – is a case in point. Don’t miss it.” Deborah Blum, Pulitzer winner, author of The Poisoner’s Handbook, and director of the Knight Science Journalism program at MIT.

“Here is a book to nourish the spirit. The Songs of Trees is a powerful argument against the ways in which humankind has severed the very biological networks that give us our place in the world. Listen as David Haskell takes his stethoscope to the heart of nature – and discover the poetry and music contained within.” Peter Wohlleben, author of The Hidden Life of Trees.

“This book breaks down barriers. At a time when we are constantly asked to choose sides, to dig in, to rally around ever smaller ideas, David Haskell examines the walls that would imprison us and, armed with science and patience, dissolves them. The book is nominally about trees, but it’s really about connections, the networks that link plants, animals, bacteria, humans, and the forces that have made such webs possible. Haskell’s trees are guideposts on a fascinating and refreshing road trip—the sort of listening tour we should require of all politicians. With a poet’s ear and a naturalist’s eye Haskell re-roots us in life’s grand creative struggle and encourages us to turn away from empty individuality. The Songs of Trees reminds us that we are not alone, and never have been.” Neil Shea, writer and photographer for National Geographic and other publications.

“This book makes you remember the fragile nature of humanity’s relationship to the world around us. David Haskell has opened up a new dimension in sound – and given us a powerful tool to rethink the way we look at the roots of our reality and how trees are the best way to guide us. A tour de force of sound and symbol. Read. Listen. Learn.” Paul D. Miller aka Dj Spooky

“David Haskell writes with uncommon insight and sensitivity: listening and giving voice to the ineluctable networks in which trees and all human experiences are embedded.” Sir Peter Crane, FRS, President of the Oak Spring Garden Foundation, former Dean of the Yale School of Forestry and Environmental Studies, former Director of the Royal Botanic Gardens in Kew, author of Ginkgo.

“David Haskell does the impossible in The Song of Trees. He picks out a dozen trees around the world and inspects each one with the careful eye of a scientist. But from those observations, he produces a work of great poetry, showing how these trees are joined to the natural world around them, and to humanity as well.” Carl Zimmer, author of A Planet of Viruses.

Literary protest, Jan 15th.

On MKL Day, January 15th, I’ll be joining other writers at a literary protest and march. PEN America and Writers Resist are co-organizing these events in response to threats to the press and to free expression under the Trump presidency.

The literary protest is on the steps of the New York Public Library. It will include readings of “inaugural” poems by American poet laureates Robert Pinsky and Rita Dove. The march will deliver a petition in support of press freedoms to the Trump transition team.

Please consider joining all living US Poets Laureate and over 150,000 others by signing the petition in defense of freedom of expression and a free press. If you’ll be in New York on the 15th, you can register to attend the literary protest and march here (or show up on the day, 2 p.m. on the steps of the New York Public Library’s Schwarzman Building at 42nd St.). Seventy five other Writers Resist events are happening across the country on the same day, listed here.

PEN America’s overview of the protest and summary of programs describe the many ways that the organization helps defend press freedoms in the US and abroad.


Some good news about land conservation from the Southern Cumberlands

From the Open Space Institute:

“In a series of six targeted land conservation projects completed within a short six-month period, nearly 13,000 acres have been acquired and added to Tennessee state parks and wildlife management areas.”

These lands add to the 17,000 acres already protected by OSI in the last few years in this region. The grants that made possible these projects aim to protect biodiversity in a changing climate. The conservation lands will also provide public access to open space and encourage sustainable forest management.

Partners in these projects included The Nature Conservancy, The Conservation Fund, The Land Trust for Tennessee, and the State of Tennessee (TN Wildlife Resources Agency and TN Dept Environment and Conservation).

Read the full press release here.


Post-truth chestnuts?

After editorial discussions that were “a bit more serious and somber …[than] in some other years,” Oxford Dictionaries has named “post-truth” as its international word of 2016. But of course we’re not “post” any truths, especially not the truths of biology and physics that don’t bend in the foul winds of demagogues.

Nor in the errors of bloggers like me. Some taxonomic truths have come to light about the not-so-somber matter of tree identification. So, with many thanks, I share my colleague Dr. Hill Craddock’s take on the “chestnuts” from my last post.

He writes that the plants in the “photo could be in the genus Castanea, with the true chestnuts…but I think they may really be fruits of trees in the genus CastanopsisCastanopsis is a large genus (more than 100 species) of Asian trees closely related to, and very much resembling Castanea.  Some species share characteristics of Quercus [oaks] and Lithocarpus [“stone oaks”].”

So, the chestnuts from China (see additional photo below) are in fact close relatives of chestnuts, sometimes called “chinkapin”. These trees are evergreen and generally not frost-hardy.

Dr. Craddock continues with “a curiosity:  ‘Shii’ is the Japanese name for Castanopsis.  Shiitake (Lentinula edodes) are grown traditionally on Castanopsis cuspidata in Japan, although in the US, they are mostly grown on oaks, or other hardwoods. Shiitake literally means ‘Castanopsis mushroom.'” So, next time you are eating some US-grown shiitake mushrooms, consider their genus-crossing journey. I’d be interested to know whether the different tree substrates result in different experiences on the palate. Does oak-grown shiitake taste the same as Castanopsis shiitake? I know that local shiitake growers here in Tennessee claim a much richer flavor for shiitake grown on solid logs rather than sawdust bricks. Perhaps the species of wood also makes a difference?

I send many thanks to Hill Craddock for taking the time to share his knowledge and to Todd Crabtree for making the inquiry that led to our exchange.

Truthiness in nuts. Castanopsis.

Truthiness in nuts. Castanopsis in southern China.

Glimpses of botanical and avian diversity at Nan Kun Shan Forest Park and Crosswaters Ecolodge

Our Chinese hosts kindly arranged a short visit to the forests Nan Kun Shan Forest Park. Driving inland from Shenzhen we first passed around the mega-city of Guangzhou — one of China’s tech hubs (the e-device that you are now reading with likely came from there) — which sits amid the anastomosing branches of many large rivers. From these urban flooplains we  passed into low hills, mostly managed for timber and fruit production, then to the steep-flanked mountains. In the mountains, protected forest parks are interspersed with vacation resorts and small villages. One of China’s first ecotourism projects is located here, the Crosswaters Ecolodge. The American Society of Landscape Architects gave Crosswaters an “Honor Award,” writing that it is, “tremendously inspiring to see a project in China that is designed as a celebration of its natural and cultural place. Impressive and extraordinary resourcefulness in salvaged and native materials make a more elegant and beautiful environment. For projects in this region it stands out for using found and salvaged local materials.” Guests stay in rooms and cabins made from locally-harvested bamboo, built in riverside forest clearings:


The plant life in this region is an interesting mix of subtropical and temperate species. Here, bamboo grows alongside banana and oaks. Callicarpa bodinieri (or perhaps japonica), Asian relative of American beautyberry, is common in the understory.

Botanical confluence: subtropics meets the temperate zone.

Botanical confluence: subtropics meets the temperate zone.

A familiar face. Smaller, denser fruit clusters than the American species.

A familiar face. Smaller, denser fruit clusters than the American species.


This oak or oak relative grows on the slopes that had not been converted to bamboo groves. I’m working on finding species/generic names…suggestions are very welcome!


Two different species of Castanea (relative of the American chestnut) grew on the slopes above the river:


Two sizes of chestnut. Neither looked or tasted like Castanea mollissima, the Chinese chestnut grown in cultivation in the US. Four other species of Castanea grow in south Asia.

Birds in this region are also spectacular:

Red-billed blue magpie. Photo by Charles Lam, Hong Kong. Creative Commons copyright 2.0.

Red-billed blue magpie, distant relative of crows and blue jays. Photo by Charles Lam, Hong Kong. Creative Commons copyright 2.0.

Black-throated tit. Relative of chickadees. Photo by Prateik Kulkarni. Creative Commons copyright 4.0.

Black-throated tit. Relative of chickadees. Photo by Prateik Kulkarni. Creative Commons copyright 4.0.

Plumbeous water redstart. These birds cling to rocks in streams, then fly up over the water to snatch insects from the air. Member of the Old World flyctacher family. Photo by Ron Knight, Creative Commons copyright 2.0.

Plumbeous water redstart. These birds cling to rocks in streams, then fly up over the water to snatch insects from the air. Member of the Old World flycatcher family. Photo by Ron Knight, Creative Commons copyright 2.0.

Our hosts were, as everywhere in China, extraordinarily welcoming. Part of our group, standing in front of the bamboo bridge at Crosswaters:


View of the forest from an observation tower at Crosswaters:



“More than 100 college presidents issue joint letter to President-elect Donald Trump”

This news from the University of the South’s website:

“Vice-Chancellor John McCardell is one of 110 college and university presidents urging Donald Trump to take a more forceful stand against “harassment, hate and acts of violence.” The campus leaders have issued a joint letter to President-elect Trump.” Read the full article here.

Thank you, Vice-Chancellor and President McCardell, for taking this stand and asking president-elect Trump to make good on his promise to be a president for “all Americans.”