Hicans and Other Useful Trees at Princeton Battlefield

When people think of trees at the Battlefield, the first and perhaps only tree that comes to mind is the Mercer Oak, which these days is Mercer Oak II, an offspring of the original, donated by Louise Morse, a remarkable woman who spent much of her long life advocating for good causes. She was wife of Marston Morse, one of the first generation of mathematics faculty at the Institute for Advanced Study.

The Mercer Oak plays an ambassadorial role for the Battlefield, a star, positioned near the road while other less heralded trees serve more prosaic functions further back.

The young oak, a teenager or perhaps a young adult at this point, is flourishing after donating much of its foliage to the insect world two years ago.

It's appropriate that the oak came from Mrs. Morse, because she herself was extraordinarily long lived, reaching 105, and, like an oak that gives of its foliage to 100s of species of insects, gave generously of her time to such causes as Stuart School and civil rights.

Closer to the house are less known but more edible trees. Beneath this one is a bumper crop of pecans, but the tree is not fully a pecan tree.

It is, instead, a hican. Like a mythical beast whose body doesn't match the head, it has the base of a hickory and the top of a pecan. You can see the change in bark from rough to smooth about six feet up on the trunk.

Chinese chestnuts, too, are having a banner year.

In front of the house, a native chestnut we planted (15/16th American), is hanging in there, though its trunk is nearly girdled by the blight.

It, too, is laden with chestnuts.

Another native chestnut on the other side of Mercer Street had looked to be flourishing, but succumbed suddenly this year. The disease does not kill the root, however, so multiple sprouts rise from the base, to be browsed on by deer.

Undeterred, Bill Sachs and I added protection to some more recently planted native chestnuts that were getting beat up by the mowers. Such a perilous world these trees enter into.

Along the field edge, the bicentennial dogwoods planted in 1976 are benefitting from the work volunteers did this spring to keep the porcelainberry vines off of them.

This shot from underneath the trees shows the wave of porcelainberry that wasn't quite able to reach the lower branches of the dogwoods.

The less shading from the vines, the more berries the dogwoods can produce to fuel the fall bird migration.

This would be the fate of the dogwoods if we didn't help them out--completely enveloped by the porcelainberry.

Two of the classic inedible trees to be found around historic homes are horsechestnuts and black locust. Clark House lacks the horsechestnut but has several grand black locusts. Black locusts provided extraordinarily rot-resistant wood for fenceposts, abundant flowers for honey, and some say they help steer lightning strikes away from the house.

With Trees, Looks Can Be Deceiving

Here's a tree that looks dead, but is probably okay. It's a horse chestnut--a species long associated with historic houses, and like many horse chestnuts lost its leaves early, perhaps due to a leaf blotch fungus. Though planted in front of a newer home, its history is connected to the 18th century house around the corner, once lived in by Joseph Stockton and, reportedly, an occasional sleeping pad for Thomas Jefferson.

And here's a recently planted ash tree a few blocks away at the Westminster parking lot, looking good but not long for the world, due to Princeton's ongoing Emerald Ash Borer invasion. When I saw that ash trees were planted as part of the parking lot expansion, I urged Westminster to get the designers to pay for replacements that would actually live long enough to shade the cars parked beneath them. Hoping I'm wrong about it all, but any followup photo a few years from now will likely show a gap where this tree now stands.

Starlings, Passenger Pigeons, and the Uneaten Acorns

Acorns, anyone? It's called "flooding the zone"--a technical term commonly used by botanists who grew up playing sports. Some people see it as a mess, and curse the trees. An alternative target for cursing, just to put it out there, would be the tree-phobic landscape of concrete and lawn that we impose beneath the trees. A forest floor is far more accommodating of arboreal excess. There, a tree can let it all hang out, let it all fall down--seeds of all sorts, leaves, branches--and the forest floor will shrug, take it all in, and turn it into wildflowers.

In town, the blanketing of acorns turns into a blanketing of oak seedlings, few if any of which have any prospects of reaching maturity. The seedlings seem to be saying, "Move me to an opening along the street where I could shade some asphalt", but it doesn't look like people are listening.

For some people, a love of trees is layered with deep resentment of this fecundity. For me, looking for logic in nature's ways, the question is not "What to do with it all?", but "What's missing?" Past posts about osage orange and honey locust ask the same question, and suggest a missing herbivore that would have consumed the abundance in the past. Botanical abundance has lost a once complementary zoological abundance.

A partial answer came this past Nov. 10, when masses of starlings swept through, congregating in the pin oaks behind our house. A closer look revealed they were gobbling down acorns. Minutes later, they were gone, having left our pin oaks a little lighter.

The starling is not native, though, so doesn't speak to what would have consumed the oaks' abundance historically. And starlings appear too small to deal with the larger acorns of other species such as red oak. Still, it's behavior suggests that the spectacular fecundity of oaks might once have fed a complementary fecundity in the avian world--some highly mobile species, large enough to deal with a broader range of acorn size, that could make quick wing across eastern North America, swooping in to feast and move on.

Enter Ectopistes migratorius, a.k.a. the passenger pigeon, a bird of spectacular mobility and historical numbers. The photos are from a wonderful NJ State Museum exhibit two years ago.

A fine writeup on the Smithsonian website says "the mainstays of the passenger pigeon's diet were beechnuts, acorns, chestnuts, seeds, and berries found in the forests." They may also have swept in to feast on the seeds of our native bamboo, Arundinaria, which at one time covered large areas in the southeast and, like other bamboos, typically bloomed only once every several decades.

It can be tempting to say that the starling is providing a service by partially filling the void left by the extinction of the passenger pigeon. A few books have come out in recent years that claim invasive species like starlings aren't a big problem after all. The books in turn embolden news editors to publish articles and opeds with a similarly seductive revisionism, showing the same willingness to cherry pick evidence and rush to conclusions. I've written detailed critiques of various of these, including one recent article that mentioned starlings.

It would be interesting to explore to what extent the massive numbers of starlings have filled the niche left empty by the extinction of the passenger pigeon. Though feeding habits may overlap somewhat, one big difference is likely to be nesting behavior. Starlings compete with native birds for nesting sites, while the passenger pigeons appear to have built nests on branches, where they would not have displaced birds seeking tree cavities.

Woody Plants With a Farmer's Tan

A couple photos to post before fall slips entirely away:

The leaves of winged burning bush (Euonymus alatus) turn bright red in full sun, or white in full shade. This photo shows the gradation on a single bush.

Please, by the way, don't plant this species, and if you have it, consider replacing it with some less invasive colorful shrub. It can be pretty, but winged burning bush has proven highly invasive in local woodlands, outcompeting native shrubs and shading out spring wildflowers.

This maple on Aiken may have gotten a farmer's tan on the top because the lower half is shaded by the tree across the street, and thus is slower to change color.

A Modern Times Moment With Persimmons

There's a scene in Modern Times where Charlie Chaplin's fantasy of domestic bliss includes reaching out the window to pluck some grapes. A cow comes to the back door to supply milk. Nature is cleverly tended to put its bounty within arm's reach.

I think of that scene every time I bicycle over Princeton University's graceful Streicker Bridge above Washington Road, ever since I noticed some native persimmon trees rising up alongside the bridge. They were planted intentionally, like Chaplin's grapes, and each year they've gotten higher, pressing their leaves and fruits closer to the fencing .

Posts from 2014 documenting the persimmon trees' rise can be found here and here, and a 2015 post is entitled "Close but no persimmon".

There's a catalpa growing within reach as well, but that's not as appetizing, somehow.

This year, the long awaited casual Chaplinesque reach was finally possible. Heading to a university soccer game, I'd check their progress.

The fencing is a real deterrent, though, as if Chaplin's dream of domestic bliss were set in a high-crime neighborhood where all the windows were barred.

At last, time and fruit seemed ripe. But wait, one problem. It's a persimmon. Can't they be astringent in the extreme? So much expectation, only to have a very pucker-mouthed ride home.

The soccer season passed less than gloriously into history, the leaves fell. A few persimmons remained on the tree, but out of reach.

Giving it one last try, I gave up on the fruits coming to me and went down below the bridge to see what lay on the ground. There, preserved on top of a leaf, was one ready to taste. It was sweet, without a hint of astringency, delicious beyond all expectation.

Sometimes dreams don't play out the way you imagined, but they can still come true.

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.

Homage to the Next Generation of Trees

One fairly rare sighting, both in Princeton's woodlands and parks and along streets, is a young tree. The great Mercer Oak that was finally blown down after 300 years of life was replaced in 2000 with an offspring, but how about all the other trees that have been lost in recent years, and will be lost if the predictions of Princeton's recently completed tree inventory prove correct? Perhaps we've gotten out of the habit of planting trees, having long been spoiled by their abundance.

This blog takes all sides on trees, praising one tree, ruing another, finding tranquility in a deep forest or opportunity in the sun-filled opening a fallen tree leaves behind, and ever thankful for how they give both in life and death.

This post offers examples of young trees growing in auspicious locations, and all the wonderful work they are already doing.

First, I'd like to thank a neighbor for letting a volunteer red oak grow in a perfect spot to shade my driveway and pickup truck. They probably haven't even noticed it, but I do. Seems like just the other day it was a little sprig peeking over the fence.

And thanks to the folks, too, who paid for a tree to be planted in Potts Park to celebrate the birth of their son. We chose the spot carefully, wanting it to eventually shade the play equipment through the summer, but not be out in the field where it might intersect with a kid running after a ball. Many swings and play structures around the world are not being allowed to live up to their full potential, abandoned by kids when they overheat in summer for lack of a tree.

Another red maple, though perhaps better to have been planted on the house side of the sidewalk, is beginning to fill one of the many gaps along our streets. We need many more trees like this one to keep Princeton's pavement from baking in the summer. The more this tree shades and transpires, the less pedestrians will perspire.

Hard to believe that not long ago this pin oak and American elm were little two foot volunteer seedlings my neighbors transplanted to their front yard. Their faith in the growth force in modest saplings, and the remarkable way time has of passing, is quickly yielding a visual buffer and afternoon shade for their house.

This backyard tulip poplar was another volunteer transplanted to a spot well away from the house.

This young backyard white oak is doing a good imitation of Mercer Oak Jr. over at Princeton Battlefield. Just beyond the fence, in Potts Park, a grove of white oaks planted by the town has matured into a favorite spot for picnics and birthday parties.

Another friend has started a pawpaw patch in their "back 40",

and a fig tree bearing delicious figs in a protected spot next to the driveway.

Though ginkgoes don't support wildlife the way native trees do (a recent article in the NY Times reports that only a few insects feed on ginkgo, while an oak serves up food for more than 500 insect species), these stilty varieties are shading the way along an improbably narrow space over at the Princeton Healthcare Center.

I like to think that the proximity of young trees, with their dynamic growth happening at our level, puts us better in touch with an aspirational energy that can feed our own. When I hear Copland's Appalachian Spring, I think of young landscapes--prairies and early successional stages. In addition to the mature beauty of a forest, we need among us these renewing landscapes, these fresh beginnings, to feed our spirit.

Ode To Willow Oak Leaves

Recently, walking through a pleasant blizzard of falling willow oak leaves on Franklin Avenue, I remembered an ode to willow oak leaves I had written in the fateful fall of 2000 while living in Durham, part of North Carolina's Research Triangle. It was this time of year, in a city whose streets were and still are lined with willow oaks, and the enormous specimen in our yard was laying down a fresh layer of soft, attractive mulch.

We had long since given up trying to grow lawn in deeply shaded piedmont clay, in favor of letting pine needles and willow oak leaves fall where they may. The pines down there are loblolly and shortleaf. Unlike the more northern white pine planted in Princeton, they are "self-pruning", meaning they drop their lower limbs to eventually become a vaulted canopy, creating an expansive, protected, cathedral-like space beneath, through which leaves and needles make their long, idiosyncratic descents to earth in the filtered light.

The piece below was published on the editorial page of the Raleigh News and Observer as one of their periodic pastoral pieces, almost certainly completely overlooked in the tumult following the Bush-Gore election that had taken place the day before.



The Work of an Autumn Breeze

The narrow leaves of willow oak spin earthwards, catching flashes of morning light. In walks along the treelined canyons of city streets, we are all victors in a ticker tape parade. The sun's rays, having lost their summer harshness, now angle into the sheltered air beneath trees, illuminating the languid descent of leaves from vaulted canopy.

Not all leaves are so elegant. Pine needles plunge earthward like clouds of arrows. The broader leaves of maples fall in rocking zig-zags. But willow oak leaves are so designed to celebrate their momentary freedom in one long graceful pirouette. They spend summer clustered overhead, anonymous in dense masses of green. Then, made expendible by autumn's chill, refined of all colors but gold, they become a million individualists in their first and last dance back to earth. In loose embrace with gravity they fall, each spinning in its own manner, at its own tempo, each captured by the sun's beaming light for all time and but for a moment.

The young girl next door tries to catch one, and quickly discovers how illusive they are--so tangible in their approach, yet like phantoms unwilling to have their only dance cut short. Having reached the ground, again anonymously massed, they mingle and merge and return by degrees to the soil from which they came.

At such times, it is hard to think of leaves as anything but a gift. In the competition between lawn and leaf for my heart, lawn has had to yield. I used to pick up the sticks, and rake the leaves, and mow threadworn grass. But now I channel my yard's sylvan tendencies rather than struggle against them. The leaves fall where they do for a reason: to soften the soil, to catch the rain, to help dogwoods through the droughts and give kids one more reason for delight. What pleasure to trace a leaf's whimsical flight, and find at bottom a sense of rightness and rest, rather than impending chore. The Triangle is a forest masquerading as metropolis, and we are the beneficiaries of its golden rain.

Durham, NC, Fall, 2000