Kentucky Coffee Tree Leaf

The size of Kentucky Coffee Tree leaves continues to amaze. Dog, looking unexpectedly Einsteinian, added for scale, next to a single leaf.

Here's another way of getting a sense for the size of the leaf, which is bipinnately compound.

Kentucky Coffee Trees Always Show Up Late For the Party

The Kentucky Coffee Trees across the street are taking their customary time leafing out, despite the warm spring. Given that each leaf is 3 feet long, waiting until the coast is clear to make such a big commitment in manufacturing is understandable. From past posts about the tree, it looks like the warm spring this year may have hastened the opening of its buds, but not by much.

The relative rareness of the tree in the wild suggests this very conservative strategy of remaining bare five or six months of the year has not proved very successful, but it probably helps these trees survive freak storms like the snow storm that hit Princeton in late October last year.

Internet sources mention it as highly compatible for planting next to passive solar homes, since it only obstructs the sun during the warmest months, and also as a tree associated with historic settlements. Wikipedia mentions a few of these trees in the gardens at Mount Vernon. The grove across the street from me grow on the original farmstead of Joseph Stockton, where Thomas Jefferson is said to have stayed on occasion.

To the left and lower right in the photo are Norway Maples fully leafed out.

Wawa Grows a Prairie

Wawhat's the Wawa growing? A bit shaggy for a butch cut. The proof is in the roof. Clearly, the Wawa at the Dinky station has gone green, or tawny, depending on the season. Take the building out of the picture, and you have a prairie out in big sky country. For a botanist, the question is not how all those prairie grasses got there--Princeton University has been designing green roofs into, or onto, a number of buildings in recent years--but whether the grass is little bluestem or broomsedge. Time to pull out the ladder for closer inspection. A vegetated roof reduces stormwater runoff from the building, and also provides insulation.

Another aspect of the Dinky Station's landscaping: Most of the trees are Kentucky coffee trees and a thornless version of honey locust. Both of these species tend to leaf out late in spring and drop their leaves early in the fall. Both are relatively rare in local woodlands, in part because their seedpods were in the deep past eaten and spread mostly by America's now-extinct megafauna. They make great landscape trees, though, because they leaf out late in spring and drop their leaves early in the fall. That means they shade the pavement and buildings only during the warmest months, then generously allow the sunlight's warmth to reach the ground during fall, winter and spring. Some research might show that the trees' internal clocks and large seedpods evolved in an ice-age world of short summers and big animals with fur the length of the Wawa's roof.

The bark of the Kentucky coffee tree has a characteristic chipped appearance,

in contrast to the smooth bark of the honey locusts.

Here's a grove of honey locusts letting October sunlight reach the south-facing windows of the Dinky Station.



Found a past post about Dinky wildlife, and a post in which the vibrations of the Dinky's approach makes the trees dream of megafauna past.

Naked Coffee Trees on Harrison Street

Here's one of the last holdouts from spring, still in its wintry hunch, bare limbs stark against a cloudy sky. Plants, like many authors and movie stars, have two names. The common name for this not very common tree is Kentucky Coffee Tree, which refers to the resemblance its seeds bear to coffee beans. It's scientific name is Gymnocladus dioicus, which may refer to its way of losing leaves early in the fall and sprouting them late in the spring. Gymno means naked.

Limb Shadow

Even deciduous trees cast significant shade in the winter, as this red oak shadow shows.

Kentucky Coffee trees--whose pods of coffee bean-sized seeds may have once catered to the culinary needs of now extinct megafauna--have a slimmer profile, due to their strategy of manufacturing very large leaves (3 feet long and 2 feet wide) rather than the more normal approach of growing lots of fine twigs to hold smaller leaves.

This species also loses its leaves sooner in the fall, and buds out later in the spring (in the photo, the Norway Maple on the left has already started to leaf out). The combination of this coarse twig structure and extended period of nakedness (thus the Latin name, Gymnocladus) make it a good candidate for planting on the south side of houses that use passive solar heating.

Ivy's Deadly Embrace

This picture tells the story of a neighbor's Kentucky Coffee Tree  laid low by English Ivy's long embrace. The smaller trunks are the ivy, which had climbed far up into the canopy of the tree. During the freak snowstorm earlier this fall, the snow clung to all that extra surface area created by the ivy, the extra weight of which toppled the tree. The fallen tree blocked the street for a week.

My backyard, too, is in an uncomfortable embrace of English ivy, in that the vine is invading from the neighbor's yard to the north,

cascading in over the ramparts facing the park to the east,

and creeping over, under and through the fence to the south. If a neighbor's runoff is flowing into my yard, I can change the contour of the ground to direct it away from the house, and consider the problem largely solved. But the flow of ivy in from neighbor's yards cannot be diverted, and instead creates a perennial chore.

The moral of this story? Never plant english ivy anywhere that its potential to spread is not blocked on all sides by lawn, pavement or foundation. Cut english ivy off of any tree you wish to live. Better yet, never plant english ivy, and remove as much as you can from your yard.

One approach to getting rid of it without working too terribly hard can be found at http://princetonnaturenotes.blogspot.com/2007/11/ivy-control-part-2.html.  Other related posts can be found by typing the words english ivy in the search box at the upper left corner of this blog.

Honey Locust Thorns and the Missing Megafauna

Why is this honey locust on Snowden Lane so bristly? The very nasty thorns once protected the tree from giant ground sloths and other megafauna common in America until about 13,000 years ago. Other trees with thorns that may once have served such a purpose are Osage-orange and hawthorn.

The extinction of some 40 megafauna species in the late Pleistocene may help explain why tree species like Kentucky coffeetree and Osage-orange are now rare. The animals that once ate and dispersed their fruit no longer exist.

An internet search led to a wonderful article on native trees adapted to giant mammals that no longer exist, likely due to overhunting by the first human immigrants to America. My pet theory is that the first American inhabitants, after driving many large prey species to extinction, learned to be better stewards of the land. Arrival of westerners precipitated a similar predatory overstepping and wave of extinctions, such as the passenger pigeon and the Carolina parakeet, followed by at least a partial shift towards better stewardship.

The article quotes Dan Janzen, now of U. of Pennsylvania, who gave riveting lectures about the symbiotic relationship between ants and acacia trees in Africa, during my college days at U. of Michigan.

Interesting Talk July 19 on John James Audubon

Because Labyrinth Bookstore's website is being updated and doesn't show events, I'm taking the liberty of posting info about this event in its entirety.

Gregory Nobles John James Audubon: The Nature of the American Woodsman  Wednesday, July 19th at 6:00 PM Labyrinth Books Princeton  John James Audubon's The Birds of America stands as an unparalleled achievement in American art, a huge book that puts nature dramatically on the page. With that work, Audubon became one of the most adulated artists of his time, and America's first celebrity scientist. In his fresh approach to Audubon's art and science, Gregory Nobles shows us that Audubon's greatest creation was himself. Please join us for presentation and discussion with the author. A self-made man incessantly striving to secure his place in American society, Audubon made himself into a skilled painter, a successful entrepreneur, and a prolific writer, whose words went well beyond birds and scientific description. He sought status with the "gentlemen of science" on both sides of the Atlantic, but he also embraced the ornithology of ordinary people. In pursuit of popular acclaim in art and science, Audubon crafted an expressive, audacious, and decidedly masculine identity as the "American Woodsman," a larger-than-life symbol of the new nation, a role he perfected in his quest for transatlantic fame. Audubon didn't just live his life; he performed it. In exploring that performance, Nobles pays special attention to Audubon's stories, some of which - the murky circumstances of his birth, a Kentucky hunting trip with Daniel Boone, an armed encounter with a runaway slave - Audubon embellished with evasions and outright lies. Nobles argues that we cannot take all of Audubon's stories literally, but we must take them seriously. By doing so, we come to terms with the central irony of Audubon's true nature: the man who took so much time and trouble to depict birds so accurately left us a bold but deceptive picture of himself. Gregory Nobles is Professor of History Emeritus at the Georgia Institute of Technology. Among his previous books are American Frontiers: Cultural Encounters and Continental Conquest and, with Alfred F. Young, Whose American Revolution Was It? Historians Interpret the Founding.

Native Trees of Princeton

An attentive reader commented that the page for "Native Trees of Princeton", which I thought I had added along the top of the homepage, does not exist. Funny, I clicked on the "publish" button but the list of trees refused to publish, nor did it magically publish itself during the ensuing weeks when my mind was on other things. Maybe Googles ever more sophisticated software detected that it still needed work, which is to say it was a bit "drafty".

Here it is, nonetheless, published as a post rather than one of those enduring "pages" at the top of the blog. It was created as a step towards fleshing out, or foliating, a rather bare tree list we have on the Princeton Shade Tree Commission website.

My apologies to any native tree species not included here. Please speak up. Catalpas, we'll talk.

ATTRIBUTES OF SOME NATIVE TREES IN PRINCETON 

This is an extensive but informal list of native trees you may encounter in the wild or in your yard, with some description, based on ten years of observation. 

Acer negundo (box elder)--Grows wild. Not commonly planted. It's soft wood can provide good habitat for birds. Considered messy and not very well formed.

Acer rubrum (red maple)--A durable, very commonly planted street tree. Also common in the wild.

Acer saccharinum (silver maple)--Common in yards and in the wild. Not often intentionally planted. Has a reputation for dropping limbs, but performs well in many yards, providing an attractive, open shade.

Acer saccharum (sugar maple)--Less common, but a sturdy, attractive native.

Amelanchier canadensis (shadblow, shadbush, serviceberry, Juneberry)--A very small tree or large bush. White flowers early in spring, supposedly when the shad are surging up the Delaware. Berries edible, but frequently attacked by cedar apple rust, so don't get your hopes up. Even our resident catbirds were disappointed.

Asimina triloba (pawpaw)--Small tree, up to thirty feet. I heard there's a wild stand behind someone's house down across Carnegie Lake, and a substantial patch in a park over in Cranbury. Plant more than one to increase prospects for the often elusive fruit. They clone, so best planted where there's a little room to expand.

Betula lenta (cherry birch)--Grows wild along the Princeton ridge. Not commonly planted in yards.

Betula nigra (river birch)--Beautiful bark and form, frequently sold with three trunks.

Betula (paper and grey birches)--These species are more characteristic further north.

Carpinus caroliniana (blue beech, hornbeam, musclewood)--Common along the Princeton ridge. Not often intentionally planted.

Carya alba (mockernut hickory)

Carya cordiformis (bitternut, swamp hickory)

Carya ovata (shagbark hickory)--Hickories are common in the wild, but not frequently planted.

Castanea dentata (American chestnut)--Devastated by the imported chestnut blight in the early 20th century. Only a few small specimens persist in the wild. The disease does not kill the root, which then resprouts. Backcrossing has developed resistant native varieties with a small percentage of asian genes, e.g. 1/16th Chinese. Some of these 15/16th native trees have been planted in parks and preserves in Princeton in an effort to reestablish the species. A few chestnuts grow along streets in Princeton, but are either Chinese or Japanese. The nut husks are very large and prickly.

Celtis occidentalis (hackberry, sugarberry)--Sturdy native, infrequently seen in the wild, underutilized in planted landscapes. They line Walnut Street across from JW Middleschool.

Chionanthus virginicus (fringe tree)--Very attractive flowers. Small tree/large shrub. Some evidence in Ohio that it can be attacked by emerald ash borer, but more evidence is needed before deciding not to plant.

Cornus florida (flowering dogwood)--Attractive small tree, commonly planted, with berries that provide important nourishment for birds migrating south in the fall. Fairly common in the wild, but an imported fungus has cut back on its numbers. It can be harder to establish that the Korean dogwood, whose fruit are eaten by monkeys in its native Asia.

Crataegus crus-galli (cockspur hawthorn)--Attractive small tree. Rarely found in the wild. Underutilized in planted landscapes, perhaps because of thorns.

Diospyros virginiana (persimmon)--Attractive mid-sized tree. Females bear fruit, which may be appreciated or viewed as messy.

Fagus grandifolia var. caroliniana (beech)

Fagus grandifolia var. grandifolia (beech)--Beech trees are common in the wild along the Princeton ridge, but are seldom if ever planted.

Fraxinus americana (white ash)--Princeton's most common tree, soon to be decimated by the arrival of Emerald ash borer. Though typically encountered in second growth forest, it can grow to a towering height, with a few extraordinary specimens to be found on campus and in older neighborhoods. Planting ash is discouraged, since all ash species will soon be dependent on chemical injections for survival. Anyone owning an ash they wish to keep should get it treated, with emamectin being the most frequently recommended insecticide to inject into the trunk.

Fraxinus pennsylvanica (green ash)--Usually found in wetter conditions, and less attractively shaped, than the white ash. Same susceptibility to emerald ash borer.

Gleditsia triacanthos (honey locust)--The wild variety has thorns and is rarely encountered, perhaps because it was spread by now extinct megafauna. The unripe seed pods have a sweet, edible inner lining. One large specimen can be found near the old gas station at Princeton Shopping Center. Planted varieties, such as those at the new Dinky station and Hinds Plaza, have no thorns, and provide a pleasant, open shade. The tiny leaflets conveniently disappear back into the lawn in the fall.

Gymnocladus dioicus (Kentucky coffee tree)--A remarkable tree, rarely found in the wild, for reasons similar to honey locust. Its very large compound leaves emerge late in spring, and drop early in fall, making the tree ideal for planting on the south side of passive solar houses. They were used in the landscaping for the Dinky parking lot.

Hamamelis virginiana (witch hazel)--Attractive small tree/large shrub. The native species flowers in late autumn, while asian species flower in the spring.

Juglans cinerea (butternut)--Rarely seen. Some are hybrids. The native species has suffered from the introduction of a fungal disease. Efforts are underway to bring back the butternut in Princeton, in parks and nature preserves.

Juglans nigra (black walnut)--Common in some wild areas, and in some backyards. Rarely planted, due to large nuts and the juglone compound emitted by the roots, which can suppress growth of tomatoes and other plants.

Liquidambar styraciflua (sweet gum)--Sturdy, large tree, common in the wild and sometimes planted intentionally. The "gum balls" it drops can be a drawback for some.

Liriodendron tulipifera (tulip tree)--Fast growing, long-lived tree that can reach great size. Flowers tulip-like and attractive, but usually too high up to appreciate. Common in the wild, but not typically planted intentionally.

Magnolia virginiana (sweetbay, swampbay)--Small tree. Can have attractive flowers. Not typically planted along streets.

Morus rubra (red mulberry)--The white mulberry (M. alba, nonnative) is also found in Princeton. A small tree. Bears abundant, edible berries similar in appearance to blackberries. The berries can be messy, and the tree lacks an attractive form. Very tasty berries, though, if you can reach them.

Nyssa sylvatica (black gum, tupelo)--Beautiful fall color. Sporadically encountered in the wild. Long-lived, sturdy. Is becoming more frequently planted along streets.

Ostrya virginiana (ironwood, hophornbeam)--Small tree. Not common in the wild, nor in the landscape trade.

Oxydendrum arboreum (sourwood)--Small tree with bright red fall foliage. Craggy form. Underutilized; may not be well adapted for the nursery trade. More common in the wild further south. Several specimens in Princeton, including one next to the church across from the high school.

Platanus occidentalis (sycamore, plane-tree)--Can be confused with the London planetree, which is a hybrid between two species, one of which is P. occidentalis. Attractive, large tree, with highly ornamental bark. Its more susceptible to anthracnose than the hybrid.

Prunus pensylvanica (fire or pin cherry)

Prunus serotina (black cherry)--The native cherries are attractive mid-sized trees typically found in earlier successional forests. They nearly rival oaks in the diversity of insects they provide food for, and so are very important for food chains.

Quercus alba (white oak)--One of the most majestic trees. The white oak "family" (those with rounded lobes, such as white oak, swamp white oak, and willow oak) are less susceptible to bacterial leaf scorch than the red and pin oaks (pointed lobes).

Quercus bicolor (swamp white oak)--Sometimes planted along streets.

Quercus coccinea (scarlet oak)--Attractive, but less commonly planted.

Quercus palustris (pin oak)--Very common street tree in Princeton. Its lower branches characteristically angle downward and often die back. Many are being lost to bacterial leaf scorch, which causes gradual dieback.

Quercus phellos (willow oak)--More frequently planted than in the past. More common in states further south. Its narrow leaves can form an attractive mulch, somewhat like pine needles.

Quercus rubra (red oak)--Common tree in the wild and along streets. Susceptible to bacterial leaf scorch.

Quercus velutina (black oak)--Encountered in the wild. Less commonly planted than red oak.

Robinia pseudoacacia (black locust)--Native to the Appalachians. Widely planted and naturalized elsewhere. Its wood is resistant to decay, it has attractive flowers, and can achieve a very attractive form with dark, craggy limbs contrasting with the foliage. Can be invasive in some habitats, and can clone, sending up young shoots armed with thorns. But some specimens in Princeton front yards are beautifully formed and well behaved.

Salix nigra (black willow)--Fast growing. Sometimes planted in low areas in the belief that it will dry the soil out.

Sassafras albidum (sassafras)--Attractive tree, common in the wild. Can clone, which may be why it's not commonly planted.

Tilia americana (American linden, basswood)--Attractive. Underutilized. Sporadically encountered in the wild. Linden trees along streets are generally not the native species.

Ulmus americana (American elm)--Though the elm was hit hard across America by Dutch elm disease, Princeton varieties have shown considerable resistance, allowing specimens to perform well and provide shade for many years, even though they may eventually succumb.

Ulmus rubra (red elm, slippery elm)


Native Evergreen Trees:

Ilex opaca (American holly, Christmas holly)--Attractive native, sometimes used in yards. Can grow eventually to 30 feet or so.

Juniperus virginiana (eastern red cedar)--Small tree. Useful in some situations.

Pinus strobus (eastern white pine)--Not encountered in the wild unless in planted stands. Its native range is to the north of Princeton. Can get big, and tends to drop large branches during ice storms.

A Hawk Does Lunch

Yesterday, a red-tailed hawk took a leisurely late lunch, perched on a Kentucky Coffee Tree overlooking North Harrison Street. Just below, cars streamed by on their way to or from the shopping center, oblivious to the lone diner. The winter menu being slim, the hawk had selected the day's special, raw rodent, from a neighbor's self-serve, backyard buffet. Hawks, it seems, don't make lunch dates but prefer instead to dine alone.

I like to think that the unlimited choice of perches, each with a commanding view, make up for any monotony in the diet. If people had the keen eyesight and dull tastebuds of a hawk, our restaurants might dispense with chefs and invest instead in vistas. Towns would inventory and protect their viewscapes to insure that all could feast their eyes to their souls' content.

Contrasts in Leaf Fall

The juxtaposition of Norway Maple and Kentucky Coffee Tree makes for a stark contrast in relative timing of autumn leaf fall. The native coffee tree (Gymnocladus dioicus) strategy for life is to play dead for half the year. Thus its latin name, which means unclad. It drops its leaves early in the fall, and is the last tree to leaf out in the spring.

To the left of the coffee trees in the photo is a Norway Maple that has yet to react to fall weather. Like many woody plants introduced from other continents, it tends to leaf out early in the spring and drop late in the fall.

The Ginkgo tree, believed at one time to be only a fossil, then found alive and well in remote valleys of China, is now a common street tree with a dramatic approach to losing its leaves,

sometimes dropping them all in one day.

Osage-Orange and the Missing Megafauna

Looks like somebody didn't finish their Thanksgiving dinner. In fact, I don't think they even showed up at the table.

This Osage-Orange, a native tree named after an Indian tribe, grows next to Princeton Pike. Indians reportedly prized their wood for bows, and colonists used them as living fences. As a species, they don't get around much anymore, mostly because the megafauna with the teeth and digestive system to eat their formidable fruit, and transport their seeds, went extinct in America more than 10,000 years ago. The megafaunas' extinction conspicuously follows the arrival of Homo sapiens to this continent.

The giants that once roamed our piece of the earth--among them mastodons, woolly mammoths, giant sloths, horses--not only transported the seeds but served other ecological services, transporting nutrients from floodplains up to higher ground and maintaining clearings with their massive appetites.

To the osage-orange, add the honey locust, Kentucky coffeetree, and pawpaw as rarely occurring species that might have once been more common if their seed dispersers hadn't disappeared.

Next Thanksgiving, for something different, consider inviting some genetically reconstituted megafauna to dinner, and don't forget the Osage-Orange.

Among many sources for more reading:
http://www.americanforests.org/magazine/article/trees-that-miss-the-mammoths/
http://www.asecular.com/forests/megafauna.htm
http://www.highlandssanctuary.org/NaturalHistory/Kamama/hall.article.htm

Greenhouse Gets a Spring Cleaning

February's native plant workshop, held this past Sunday, was like one of those White Tornado commercials from the 60s, a whirlwind of clean energy zipping through the Mountain Lakes greenhouse, putting everything in order. Pots were stacked, space was cleared for growing the coming season's wildflowers, and Kim led a project to render the unlatchable greenhouse door once again safe and functional.

Prior to the cleanup, we had walked up the long driveway, identifying woody plants as we went. Everyone got up to speed on distinguishing native spicebush from exotic shrub honeysuckle and multiflora rose. And then we started identifying trees by their bark and form. Shagbark hickory lived up to its name, the walnut bark was dark with deep furrows, the red oaks had flat, gray "ski tracks" running down the trunk, and a Kentucky coffee tree had gray "potato chips" flaring out. There were also some very impressive black cherries, pignut hickories and silver maples. Tiny red spots on the pavement proved to be fallen flowers from the silver maples, which get an early start on spring.

Susy of the Whole Earth Center provided cider and cookies. There were nine of us, all told. Thanks to all!

-- These native plant workshops are sponsored by Friends of Princeton Open Space and the Whole Earth Center.