Category Archives: Trees

Autumn at the National Bonsai and Penjing Museum

En route to giving a lecture, I stopped by the bonsai collection at the National Arboretum in Washington DC. The trees are in their full autumnal splendor:

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Are these trees pitiful captives? In The Songs of Trees I argue, no, the trees — some hundreds of years old — have exchanged the community of a forest for the community of human care. A merger of lives.

Eyes on hemlock

I was in Vermont this weekend for the Northern Woodlands conference (for those not familiar with the group, I highly recommend their wonderful magazine and impressive programs). Along the way I saw wonders: Healthy eastern hemlocks!

After seeing mountainsides of hemlock reduced to browned standing dead trees in the Southern Appalachians, these trees were a balm for my eyes and mind. The cause of tree mass die-offs is the hemlock woolly adelgid, an insect introduced from Japan. The adelgids pierce hemlock leaves with their needle-like mouthparts, drawing down the trees’ energy reserves and causing dehydration. In the space of a decade, hemlock went from being one of the more common trees in many eastern forests to being an ecological ghost.

Native birds and tree-dwelling insects depend on the hemlock. Less obvious are the dependencies of aquatic creatures. Hemlock shades mountainside streams, cooling the water. Cool streams hold more oxygen than warmer ones, so hemlock death can cause streams to become less welcoming to insects, salamanders, and fish. Hemlocks also soak up rainfall and evaporate moisture back to the air. Their loss has changed the rhythms and amplitudes of water flowing from the mountains.

Much of Vermont is too cold for the invasive hemlock woolly adelgid, so hemlocks continue to thrive. Warmer winters and an endless supply of new insects from the south will present a challenge in coming years. For now, the northern woods are the hemlocks sanctuary, and thereby a refuge for the many other species that depend on hemlocks.

US Forest Service range map of hemlock woolly adelgid (2016). The insect continues to move west but cold temperatures keep the invasive species out of northern forests.

Tree gutted by lightning

A bolt knocked the crown off this tulip poplar, splitting the tree down to the roots in the process. A fire then started in the split trunk, hollowing it out. Now the trunk is a tube, entirely charred inside. In the mid-section of the tree the bark and remaining wood is no more than a few centimeters thick. Up top, several branches are still alive.

Trees are not the only witnesses to lightning strikes. NASA detects “flash rates” of lightning across the globe from sensors in orbiting satellites. The image below uses this NASA data to map lightning strikes (fromNOAA’s Science on a Sphere project; click on “view interactive sphere” on the right-hand side of the page to view your own part of the world). Map projection: from orbit, where North means nothing.


Alder in bloom. Now a common sight in February.

On the lakeshore, a smell of springtime mud and wet leaves. Soil microbes are getting a boost from the unseasonably warm air and our noses are soaked in their festivities, an aroma-pulse of decomposition.

I push forefinger against thumb, then flick, I tap an alder catkin. A cloud of lime-yellow pollen drifts down to the lake water.


Smooth alder (also called hazel alder, Alnus serrulata)

Alders are monoecious, that is they have separate male and female flowers on the same plant. The male flowers mature before the females, preventing self-pollination.

Male flowers hang in pendulous catkins. They are furry, soft, floppy, cute. Like kittens, hence the name. From 16th century Dutchkatteken, a little cat.


Female flowers just before they mature and receive pollen.

Female flowers several days later. Their sticky surfaces are now covered by captured pollen.

Female flowers several days later. Their sticky surfaces are now covered by captured pollen.


Later in the year the female flowers will swell and harden into small cone-like strobili. These look like cones, but alder is a flowering plant, an angiosperm not a cone-bearing gymnosperm like a pine.

Last year's strobili, their seeds now either shed into the wind or stolen by birds.

Last year’s strobili, their seeds now either shed into the wind or stolen by birds.

A little early for flowering? Not any more. Plants are shifting their bloom and bud-break earlier as the climate warms. For example, a study in the Washington DC area found that over the last 30 years of the 20th century, alder moved its blooming date 11 days earlier. Most species are following suit, but not all at the same rate. Non-native species like privet, bittersweet, and multi-flora rose are less tied to native seasonal rhythms and so are better able to exploit the early springtime warmth.

Witch hazel’s obstinacy

In the bleak mid-winter…time to bloom? Witch hazel, Hamamelis, proffers its flowers to the snow. Such willful disregard for the seasons is a refreshing sight, suggesting that we, too, might sometimes deck ourselves in vernal finery, despite the weather. Expect little reward, though. So few pollinators visit that fewer than 1% of flowers form any seed. Why, then, such obdurate insistence by witch hazel on winter blooms? Perhaps to keep the few flying pollinators on warm winter days to itself and thus avoid cross-pollination with undesirable kin? Perhaps.



According to OED via Etymology Online, “witch” is “probably from Old English wice ‘Applied generally or vaguely to various trees having pliant branches'”. Bending the rules.

Tree guards of New York: story fragments.

The rails, gratings, and fences that enclose the trunks of New York’s street trees are signifiers and indicia. Some of the nature of the human community is revealed in these constructions. A sampling of this diversity follows, photos mostly from Brooklyn, a few from Manhattan. Each is a sculpture — sometimes self-consciously so, sometimes without such intention — or a fragment of narrative captured in concrete, metal, wood, and soil. I’ve photographed these tree surrounds in many seasons. Those that follow are from late December, 2016.

(Click on any of these images to see them in slideshow format:)


The tree that owns itself?

Finley Street in Athens, Georgia, is partly blocked by a curved stone wall. Cars must slow and twist their way around the obstruction. As they do so, they pass under the branches of an aristocratic white oak tree: this plant is, they say, landed gentry. The oak owns the land on which it stands.

Such a tree deserves a high-five:

tree that owns itselfii

From the deed, first reported in the Athens Weekly Banner in 1890:

“I, W. H. Jackson, of the county of Clarke, of the one part, and the oak tree, (giving location) of the county of Clarke, of the other part: Witnesseth, That the said W. H. Jackson for and in consideration of the great affection which he bears said tree, and his great desire to see it protected has conveyed, and by these presents do convey unto the said oak tree entire possession of itself and of all land within eight feet of it on all sides.”

A great story, but no such deed was ever recorded in the Clarke County courthouse. Yet the story lived on and, therefore, so did the tree. Legal title is not the only way to avoid the ax, a catchy narrative will do the same. By 1906, the tree was protected behind decorative chain and granite posts. The posts were accompanied by a plaque, standing to this day, with a quote from the non-existent deed.


In 1942, a windstorm killed the oak, but the tree’s admirers — humans, not the oaks’ usual squirrel attendants — were prepared and had already gathered and germinated acorns. Today, the force shield of human story-telling still protects the tree’s offspring from development and road-straightening. Can stories be as powerful as legal paperwork?


The map from by the county tax assessor’s office shows a jog in the road, but no property lines. Does the tree pay taxes? I could find no record of the portion of the annual oak mast taken by local government. What might happen to revenue from an oak tax? Acorn-fattened hog is a southern delicacy: pork barrel spending?

tree owns itself tax map


Special thanks to Dorinda Dallmeyer and Claiborne Glover who took me to see the tree during my visit to Athens last week. My thanks also to the sponsors of my lecture at the University of Georgia: the Environmental Ethics Certificate Program, the Integrative Conservation Graduate Student Organization, and the Wilson Center for Humanities and Arts.


Athens-Clarke County Board of Tax Assessors & Appraisal Office.

E. M. Coulter, 1962, The Georgia Historical Quarterly 46: 237-249

Photo credits: D. Dallmeyer (palmed tree)