Which hawthorns are at Bartram’s Garden, and where are they?

Joel Fry, Curator at Bartram’s Garden, answers these questions, and more….

[please note that hawthorn (= the genus Crataegus) taxonomy contains many uncertainties, and that Joel has noted where modern names are not clearly applicable to historic names and where identification of plants is not clear cut – and hence the use of words like “possibly” and “likely”, inter alia]

The 3 trees southwest of the Bartram House all seem to be Crataegus flabellata, fanleaf hawthorn.

The tree that is southeast of the Bartram House and down the steps from the upper terrace (i.e., in what we call the “Lower Garden”) is likely Crataegus succulenta var. macracantha, fleshy hawthorn.

The tree at the southeast gate to the historic garden is Crataegus mollis, downy hawthorn.

Additionally there are a number of hawthorns planted on the entry drive, and there are others that may have been planted or may be volunteer seedlings.

Along the Bartram village side of the entry lane are many Crataegus phaenopyrum, Washington hawthorn. These were planted in the 1950s by the John Bartram Association. There are also a few isolated Washington hawthorns on the CSX railroad [this refers to the railroad tracks that pass through Bartram’s below grade] side of the entry, that look larger and may have been planted earlier, in the 1940s or 1930s.  But at that date the current entry road to the garden did not exist, so it seems an unlikely place for planting. They might be volunteer trees that sprouted in the brush along the railroad in the first half of the 20th century.  Or they could have also been planted in the 1950s, but grew larger due to better conditions.

There is also a large, old Crataegus crus-galli, cockspur hawthorn along the CSX side of the entry, that recently lost most of its top growth, but still seems alive. This is a very large hawthorn that could easily date to the first third of the 20th c. There are other cockspur hawthorns as volunteer trees throughout the entire site. There is one very near the gate into the administration building and garden barn, and several down along the river bank in the wetland at the foot of the historic garden.

There is another very large volunteer hawthorn along the main CSX railroad line just before 54th and Lindbergh. It grows right on the edge of the cleared bank at the railroad bridge, and is lately partially engulphed in paper mulberries. This hawthorn also looks like a volunteer tree, as it is halfway down the slope of the railroad cut. I saw recently the tree is now covered with a very large quantity of large scarlet fruit. It is different from any of the other Crataegus in the garden, and may be Crataegus pedicellata (C. coccinea), scarlet hawthorn, which has large clusters of large, soft fruit.  This scarlet hawthorn seems to grow like the downy hawthorn with a larger trunk and large, wooly leaves, but much more fruit which is scarlet, rather than yellowish orange. It also looks to be free of the rust or fungus that attacks some of the other hawthorns and their fruit.

Crataegus pedicellata, scarlet hawthorn is one of the hawthorns recorded for the John Bartram period so it would be useful to have more examples, and it may be one of the most attractive/useful of all the native hawthorns.

There are also 2 or more hawthorns in the historic Orchard tract, mostly along the edge of the 1838 railroad cut. These don’t fruit well, and are currently much overgrown,  covered with porcelain berry or other vines, so it’s difficult to identify what they might be.

Additionally, Joel supplies the names of Crataegus that John Bartram used in his seed box lists in the 18th century:

Firstly: John Bartram generally used the genus “Crataegus” to mean what is now called Amelanchier, or Aronia/Photinia, although he also used the genus “Mespilus” to mean some modern Amelanchier.  I think this relates to the great variability of stamens that forced theses several genera into different Linnaean Classes–one of the great failings and confusions of the original Sexual System.

When John Bartram named what are now considered Crataegus he almost always called them some type of “thorn” in English. [These names range from 1754-1769]

Bartram’s “narrow leaved thorn” or “cockspur thorn” = modern Crataegus crus-galli

“broad leaved thorn” = Crataegus flabellata (possibly)

“dwarf haw” = Crataegus uniflora (possibly)

William Bartram’s plant lists add a few more Crataegus species, that were likely growing at Bartram’s Garden. In 1783 he (Willam Bartram, that is) adopted the genus “Mespilus” in describing all the hawthorns. Like his father he used “Crategus” [Willam Bartram’s spelling] for modern  Aronia/Photinia  and some Amelanchier.  [All from the 1783 broadside Catalogue of Bartram’s Garden.]

“Mespilus Spinoza, Cockspur Hawthorn” = Crataegus crus-galli

“Mespilus Apiifolia, Carolina Hawthorn” = Crataegus marshallii

“Mespilus Azarol, Great Hawthorn” = Crataegus mollis (possibly)

“Mespilus Humilis, Dwarf Hawthorn” = Crataegus uniflora (possibly)

[Note: there was a Crataegus named for John Bartram, that was collected, by Alexander MacElwee, at a locality noted as “Lane near Bartram’s old garden” on “June 3, 1901”, and given the name “Crataegus bartramiana, specimens of it are currently at the herbarium of the Academy of Natural Sciences (PH); it was also collected by MacElwee on 20 September 1902 and B. H. Smith on the 24th of May 1905 and the 25th of May 1912 (noted as from “type tree!”).  There is also a record of Crataegus tatnalliana growing at Bartram’s, from a collection at PH, collected by B.H. Smith on the 28th of August 1904, and also a note in Keller and Brown’s 1905 Flora of Philadelphia]

For more about Bartram’s:

Rhubarb

Some botanical history

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The white pines of Cresheim Creek

Cresheim Creek is a tributary of the Wissahickon, and where these two waterways meet is called Devil’s Pool.  People have been swimming at Devil’s Pool for centuries, diving off the high rocks and into the deep pool below, having cookouts on the side, and sitting in the cool water on the hottest of summer days – it’s been like this for hundreds of years, cool water on a hot day has always drawn us to it, and probably always will. That cool water carousing out of Cresheim Creek runs down all the way from Montgomery County, where the headwaters of Cresheim spring forward, up near the USDA research facility on Mermaid Lane.  That water quickly cuts into Philadelphia, running alongside an old Pennsylvania Railroad spur that came off of the Chestnut Hill West line, a spur jutting off that main branch, popping off in a northeasterly direction – its railbed then crosses Germantown Ave and ducks underneath a trestle of the Chestnut Hill East line, which was a Reading Railroad train.   These lines and companies didn’t touch, but where they came close to each other, Cresheim Creek ran beneath them just the same.  And while that old train bed along which Cresheim Creek flows doesn’t run rails anymore, it is still there, a remnant of a time when trains lined the city in far higher resolution than they do today, and of a time when they followed streams instead of piling over them.

Thomas Moran’s painting Cresheim Glen, Wissahickon, Autumn captures how this waterway looked in the mid to late 19th century, with a white oak to one side (the viewer’s left), a sycamore to the other, tumbled rocks in the water, and a wide open space just beyond. As it rolls through Philadelphia, Cresheim Creek runs alongside Cresheim Valley Drive, cutting through deep rocks, and then into a wider plain.  At about this opening, just southwest of the train bridge for the Chestnut Hill West line, there used to be a recreational lake, called Lake Surprise – this was there about a hundred years ago and is no longer there.  Lake Surprise was constructed after factories upstream, like the Frances Carpet and Dye Works, had closed, thereby keeping the lake’s patrons unstained.

Cresheim Creek used to have quite a bit of manufacturing – below where Lake Surprise once was, and just southwest of the McCallum Street bridge, there was a paper factory up until as recently as about a hundred years ago.  While none of those mills or factories remain today – Cresheim Cotton Mills and Hills Carpet Factory have long been closed – evidence of them is still clearly there, as you walk along stone roads in the middle of the wooded banks of the streams.  This is especially noticeable southwest of McCallum, southwest of where Lake Surprise used to be, where cut and trimmed rocks line paths that once carried wagons to and from the mills and are now sitting overgrown, with plants diving in from the sides.  A stone bridge used to cross the creek, just downstream from where the McCallum Street bridge passes far overhead; that stone bridge, whose remnants still remain, was crumbled in a flood in 2004.  To see what that area under McCallum looked like in the 19th century, see here: http://digitallibrary.hsp.org/index.php/Detail/Object/Show/object_id/224 )

Further onwards, downstream, towards the Wissahickon, past McCallum, there is a dense woods on either side of Cresheim – as you look you’ll see reminders of the horticulturally developed areas nearby, plants such as a Styrax (planted about 16 years ago – we cored it to find out), a hardy orange (Poncirus trifoliata), and many once-cultivated viburnums that have escaped into the woods; all of these are there and kind of pop out at you, if you’re looking. There are also hundreds upon hundreds of other plants that came in with a bit less of our help – beeches and birches and ferns and flowers that seeded or spored in due to the efforts of the wind, water, or animals other than humans, and though sometimes they might’ve had some help getting to this area, some have figured out how to get around on their own, like the umbrella magnolia, for example.  (I note here that, as Rob Loeb has sagely pointed out to me, in Fairmount Park it is often unclear whether a plant was planted by people or not – for example, we generally say that beeches on rocky slopes came there on their own, however, beeches were planted in the early part of the 20th century, and trees we see now may well be remnants of what were planted by people at that time, in what is appropriate habitat for that species; for an example of documentation of beech planting for forestry, see Joseph Illick’s “Pennsylvania Trees”, printed in 1928 [“Reprint of Fifth Edition of 1925”, Bulletin 11, PA Dept. of Forests and Waters], where the caption to Fig. 29 (“Thinned Scotch Pine”) includes the following: “About 70 years old.  Underplanted with Beech”)

And there are even plants here that are parasitic upon other plants, such as Conopholis americana, or Squaw-root, noted by Keller and Brown (1905) with a locality of “Wissahickon”, and that Barton (1818) noted as “Parasitic. On the authority of Mr. Bartram, I have introduced this plant, never having met with it myself. He says it grows in the woods near Philadelphia. Perennial. July.” There are also plants that were once here that we no longer see, like the pawpaw (Asimina triloba), which I have yet to see growing in the Wissahickon or along any of its tributaries, but if we take a look at Barton (1818), we find that it was here:

“Papaw-tree is very rare in this vicinity, and here its fruit seldom comes to maturity.  It is a very small tree, with deep brown unhandsome flowers, and an oblong fleshy esculent fruit, about three inches long, and one and a half in diameter.  On the Wissahickon; and on the road to the falls of Schuylkill, west side of the river, and about three miles south of the falls; scarce”

Keller and Brown (1905), in their flora of Philadelphia, list a locality of “Wissahickon” for the paw paw, but it is not to be found in Jack Fogg’s checklist of plants of the Wissahickon (published in 1996 in Bartonia), and as just mentioned above, I haven’t seen it here (though it does grow elsewhere in Philadelphia today).

And so the plants have changed – some that weren’t here historically are here now and some that were here previously no longer are.  But the forest is still here, in a variety of different forms and structures. One spectacular stand of woody plants is up a hill that is somewhat steep, and not too far southwest from McCallum Street, and on the southeast side of the stream.  There, there is a magnificent stand of mountain laurel, flowering in the spring underneath very large chestnut oaks.  These might have been planted.  They might not have been planted.  But either way, they flower in the spring and as they shed their leaves in the fall they leave behind magnificently crooked branches straggling towards the canopy above.

A little bit farther downstream from there, downstream from that stand of mountain laurel and chestnut oak, but before you get to the Devil’s Pool where Cresheim Creek empties into the Wissahickon, there is a dense stand of eastern white pines (Pinus strobus), a stand filled with very large trees. Many, if not most, of them are well over 2 feet across and tower a hundred plus feet over your head as you walk among them.  It is a uniform stand of trees, pretty much all white pines, with their soft needles making for quiet walking along the paths that wander over their roots, and very little underbrush to block your way.  I’ve been coming to Cresheim for years, and this site is one of the most striking there – and for many years, I’d thought of it as a scene right out of pre-colonial Philadelphia, before there was a Philadelphia.  This was how it must have looked, I thought.  Enormous white pines, tall like the ship masts they would’ve become if this were three hundred years ago, filling in the woodland scene.  White tailed deer would’ve run beneath, turkeys would’ve gobbled in there, too – this would’ve been nature at its cleanest, its purest, its finest.  This is how Cresheim Creek must’ve been , I thought, and how much of the Wissahickon would’ve looked before we got here. But that’s not how it would have been, not even close.  Unknown to me then but known to me now is that the white pine is not native to Philadelphia.  While it is native to Pennsylvania, it is not native to our city – it was not here, most likely, when Europeans arrived, and it quite certainly didn’t fill thickly the woods with uniform stands, like this stand at Cresheim Creek does today.

How do we know this?  Well, one reference to use to answer this kind of question is William P. C. Barton’s Compendium Florae Philadelphicae, written in 1818.  Dr. Barton was the nephew of Benjamin Smith Barton, the man who trained Meriwether Lewis in botany, and the younger Barton was also a botanist, at the University of Pennsylvania, just like his uncle.  And he (William P. C., that is) wrote a book that listed all the plants in Philadelphia at his time. Pitch pine (Pinus rigida) is there, and even noted as being “on the Wissahickon”.  So is what was called at the time yellow pine, but we now call short leaf pine (Pinus echinata – though Barton calls in Pinus variabilis).  But the eastern white pine, Pinus strobus, is not there, it is not listed in Barton’s flora of Philadelphia.  And so we can reasonably confidently say that this tree was not here in 1818. Addtionally, Peter Kalm, Finnish botanist and student of Linnaeus, when he was here in the late 1740s, he didn’t see it, though he did see it in Albany in June 1749, writing “The White Pine is found abundant here, in such places where common pines grow in Europe.  I have never seen them in the lower parts of the province of New York, nor in New Jersey and Pennsylvania.” (Travels into North America, by Peter Kalm, translated by John Reinhold Forster); he most likely would have noted such a valuable tree, and where it was, and so this is further evidence that this tree wasn’t here.  (this was a tree of great value, so great that in 1710 there was passed in England: “An Act for the preservation of white and other pine-trees growing in Her Majesties colonies of New-Hampshire, the Massachusets-Bay, and province of Main [sic], Rhode-Island, and Providence-Plantation, the Narraganset country, or Kings-Province, and Connecticut in New-England, and New-York, and New-Jersey, in America, for the masting Her Majesties navy “) Additionally, in Ida A. Keller and Stewardson Brown’s 1905 Handbook of the Flora of Philadelphia and Vicinity, published by the Philadelphia Botanical Club, they do list the eastern white pine, and note it as being present in Bucks County, and Montgomery County, and Delaware County, and Chester County, and Lancaster County, and Lehigh County – throughout southeastern Pennsylvania, you’ll note.  Except in Philadelphia. And in Thomas C. Porter’s 1903 Flora of Pennsylvania, he lists it as being in Chester and Lancaster and Blair and Huntingdon and Montour and Erie and Tioga and Delaware and Luzerne and York and Allegheny counties.  But not Philadelphia. And so, the evidence points pretty clearly to the eastern white pine, Pinus strobus, as not being native to Philadelphia County.  We do see it growing naturalized here now, but it got here, to Philadelphia, with our help.  It isn’t clear when it became naturalized (that is, reproducing and growing on its own) here, though it is pretty clear that this occurred by the 1960s.  It is in Edgar Wherry’s “A check-list of the flora of Philadelphia County, Pennsylvania” (published in Bartonia, the Journal of the Philadelphia Botanical Club, vol. 38), and this came out in 1969, and there is a collection of Pinus strobus from Dr. Wherry in the herbarium of the botany department of the Academy of Natural Sciences (PH) with label data stating: “Seedling from old (though probably planted) tree, Schuylkill Valley Nature Center, 1 mile west of Shawmont / October 27, 1967” (NB: this is the only collection of P. strobus from Philadelphia at PH, and I also note that there are none from Philadelphia at GH; I looked in June of 2013.  There are three listed in the NYBG online database, one collected by Isaac Martindale, July 1865, in Byberry, but it is not noted if it was cultivated (NB: Martindale commonly collected in gardens, as is noted in Meyer and Elsasser 1973 [“The 19th Century Herbarium of Isaac C. Martindale”, Taxon 22(4): 375-404]: “His earliest collections date from 1860 when he started to collect plants in his garden and environs of Byberry and from the garden of his uncle, Dr. Isaac Comly, who also lived at Byberry. Martindale left a fairly good record of cultivated plants of the Bartram garden in Philadelphia, of Thomas Meehan’s nursery in Germantown, Pennsylvania, from his own garden, and from other gardens in the Philadelphia area.”; additionally, this species has been commonly planted in the region for quite some time, e.g, as is noted in William Darlington’s 1826 Florula Cestrica, of Pinus strobus: “This is a handsome tree; and when met with, is generally transplanted about houses, as an ornament.” – he also notes it as being ‘rare’ [this refers to Chester County, PA]); there are two additional collections of P. strobus from Philadelphia, at NYBG: two duplicates of var. “fastigiata”, collected in 1980 and noted as being cultivated).  Also, in the archives of the Academy of Natural Sciences, there is a document, by Charles Eastwick Smith, a “Catalog of the phaenogamous and acrogenous plants (found within 15 miles of Broad and Market streets, Phila., and in the herbarium of C. E. S.)” … “found in 1860-1868”, and in it P. strobus (on p. 24) has a dash next to it, indicating its presence within that range at that time; however, there is no indication if it was in Philadelphia, or just nearby.  And this stand itself has been documented as being planted, by J. C. Tracy, in his paper “the Breeding Birds of the Cresheim Valley in Philadelphia, 1942“, published in Cassinia, where he writes “Near the mouth of the creek a large stand of white pine has been introduced on the south slope.”  Also, in Norman Taylor’s 1915 Flora of the Vicinity of New York, which includes Philadelphia, he notes of the range of P. strobus: “PA. Throughout”, but he doesn’t site any specimens or give details as to whether it was specifically found in Philadelphia; and so while this suggest that the white pine might have been naturalized here by 1915, it doesn’t suggest it strongly, and so it is as yet unclear as to when exactly this tree became naturalized in Philadelphia. But anyway… by the sixties it’s pretty clearly documented that it was naturalized here.  But it most likely was not in the 19th century, the earliest 20th century, or before.  Additionally, this stand in Cresheim Creek is an even-aged stand, most of them being about the same size (and therefore, by inference, all being roughly the same age), and most of them are on a hill, sometimes a pretty steep one.

And so this is pretty clearly a stand that was planted, because if it was a stand that had seeded in on its own, we would see trees of many different ages in there.  And so, not only is it not a plant that was here prior to the 20th century, but this is not a naturalized stand either.  People planted these. White pine was a popular plant to plant, about a hundred years ago, and that’s roughly (and the “roughly” part here will become more important later, by the way) when these were planted. At the turn towards the 20th century, the white pine was just so clearly a tree to be used in forestry, that a forester in Pennsylvania could write:

“It is not necessary to state the uses of this tree nor should it be necessary to state that it ought to be cultivated extensively.  It is a rapid grower and prefers poor soil, yields early returns and is very valuable when mature – what more is wanted?”

(The above quote is from the “Statement of work done by the Pennsylvania Department of Forestry during 1901 and 1902, together with some suggestions concerning the future policy of the department, and also brief papers upon subjects connected with forestry.”, Chapter VII “Propagation of forest trees having commercial value and adapted to Pennsylvania.”,  by George Wirt, Forester – this work can be found in the library of the Academy of Natural Sciences of Philadelphia) As we see, white pines were commonly planted about a hundred years ago, and this is an even aged stand of about that age, and therefore it is quite clear that this stand of white pines was planted, and didn’t seed in on its own. Additionally, as Alexander MacElwee writes in the “Trees and Wild Flowers” section of T. A. Daly’s “The Wissahickon”:

“White Pines are frequent. In recent years thousands of seedling pines have been planted with a view to reforesting naked slopes. These consist principally of the White Pine, Red Pine, Jack Pine and short leaf Yellow Pine.”

OK, so this is a plant that is not native to where it is now planted, and it was planted by people.  Also, it is on a hill, so it was most likely planted to control soil erosion, which further implies that it was planted not so much for a “natural” aesthetic (though that may well have been part of it), but moreso for a civil engineering project.  It is a wonderfully beautiful stand that really does make us think about what is “natural”, just from what we have seen of it so far.  But that isn’t all. Additionally, the seedlings that were used to plant this stand were quite possibly imported from Germany.  Up until roughly (and again, that “roughly” will be important in a bit) a hundred years ago, many if not most of the white pine seedlings planted in the US were imported.  Why?  Why would Americans import, from thousands of miles away, a tree that is native to the US? Because it was cheaper.  Germany, and a few other countries, had the comparative advantage in terms of skilled labor and economics of scale, and foresters in the US took advantage of that, buying in the less expensive, high-quality imports from across the sea.  An article written by Ellicott D. Curtis, published in Forest Quarterly, volume VII, from 1909, clearly outlines the economics of this.  He quotes a cost of 95 cents per thousand for white pine seedlings in Germany – he then cites freight costs as 50 cents (to New York) and duty as $1.15 (for import into the US), for a total cost of less than $3 per thousand, as the sale price in New York.  He contrasts this with prices from various American producers, the lowest of which is $5 per thousand (from Harvard Nurseries in Harvard, Illinois). Even with transport costs and duties, it was still cheaper to import from thousands of miles away.  Curtis also notes the low volume of US production:

“I desire further to call attention to the fact that the raising of trees for forest planting is a comparatively new industry…”

It was cheaper to buy them as imports, and also, they would not have been readily available via domestic production. And they were planted densely, as we see from this excerpt from Areas of Desolation in Pennsylvania, by Joseph Trimble Rothrock (formerly Commissioner of Forestry of Pennsylvania), which came out in 1915:

“To plant an acre of young white pines 1,000 seedlings of say three years’ growth would not be an excessive number; in fact, 2,000 would be nearer the mark.  They are started close, in order that in search for sunlight, tall, straight trunks may be developed.  As they grow and crowd each other, the weaker ones are removed.  The process of thinning continues until the timber has reached marketable size.  From the time the young trees are 20 feet high they begin to have a value, and by sale of those removed, income (small at first) begins to come in.” (p. 21)

And so, as of 1909, imports of eastern white pine supplied the needs of the US, and they were planted by the millions, these immigrant plants, spreading industriously across the land. But this was not to last for long – shortly thereafter, the white pine blister rust decimated the importation of white pines, as it decimated the white pines themselves. White pine blister rust is a fungal disease of five needle pines.  Pines are conifers, and they have needle shaped leaves, as do most other conifers.  Pines, however, unlike other conifers, have their needles bundled together into what are called “fascicles”, with a papery sheath at the base of those bundles.  There are, broadly speaking, two kinds of pines: five needle pines (Pinus strobus, the eastern white pine, is a five needle pine) and two-or-three needle pines (Pinus rigida and Pinus echinata, both mentioned above, are in this latter group).  Within those groups, there are many kinds of pines, but every species of pine can be set into one of those two groups – they either have five needles, or two-or-three needles. And the white pine blister rust hits the five needle pines, and brutally.  It came into North America around the turn towards the last century, sometime around 1900 (by 1906 it was definitively here), and it rapidly began to kill the white pines, and by the 1910s it was wiping them out. There were many responses to this botanical epidemic, but they were for naught, despite the best efforts of foresters across the nation.  In addition to the general difficulties of controlling disease, which is always a sisyphean task, this was a time when the US, and the world entire, was incredibly strained. A summary of “The White Pine Blister Rust Situation”, published in Forest Leaves (published by the Pennsylvania Forestry Association) in 1919 covers this pretty well:

“We may congratulate ourselves, not on the measure of success with which our work has been carried out the past season but upon the fact that we have been able to work at all.  The loss of men due to the draft, to war industries, the difficulties of housing and lodging, general increased expense of the work, the poor quality of much of the available help, and during the last two months the epidemic of influenza – all have greatly increased the difficulties of our work.”

There were a number of eradication efforts that were implemented as could best be done with the exigencies of the time, but most importantly for our story here, it was recognized that this disease had arrived via imported plants, and so a response, a major response, was an act of Congress – the Plant Quarantine Act of 1912. And “Quarantine No. 1” was against the white pine.  The implementing language is as follows;

“Now, therefore, I, Willet M. Hays, Acting Secretary of Agriculture under authority conferred by section 7 of the act approved August 20 1912 known as the Plant Quarantine Act do hereby declare that it is necessary, in order to prevent the introduction into the United States of the White Pine Blister Rust, to forbid the importation into the United States from the hereinbefore named countries of the following species and their horticultural varieties, viz. white pine (Pinus strobus L.), western white pine (Pinus monticola Dougl.), sugar pine (Pinus lambertiana Dougl.) and stone or cembrian pine (Pinus cembra L.)”

I include the above not simply as documentation, but because Hays was, I believe, the only writer ever to use more commas than I do.  The rule continues:

“Hereafter and until further notice, by virtue of said section 7 of the act of Congress approved August 20, 1912, the importation for all purposes of the species and their horticultural varieties from the countries named is prohibited.”

And henceforth, importation of white pine seedlings was no more. This is not to say that white pines weren’t grown and sold in the US – they had been sold in the horticultural trade, and this continued to be the case throughout the time of the epidemic.  In the 1900 Meehan’s catalogue (Meehan’s was a major nursery, located in Philadelphia), they write of the white pine that “This useful native species is very well known.”  And the white pine was sold continuously in the horticultural trade, across the time of the Quarantine (Pinus strobus is in the 1906, 1907, 1908, 1909, 1910, 1911, 1912, 1914, 1916, 1919 Andorra catalogs – Andorra was another major nursery, also in Philadelphia).  [The above noted catalogs are at the McLean Library of the Pennsylvania Horticultural Society] But the seedlings were no longer being imported, and the white pine was not a plant that had been grown in the US for large scale production.  It was being grown for the relatively small amounts needed for horticultural plantings, but not by the millions that would’ve been needed to supply the needs of foresters. Because of this, white pines were not commonly planted for years after the Quarantine came along in 1912, as domestic production needed time to increase to meet the needs left wanting by the lack of imported materials. Even by 1915, US production was moving healthily forward, as is indicated in this excerpt from Rothrock’s Areas of Desolation in Pennsylvania:

“A senator of the United States, a gentleman who had made his fortune by lumbering, once stated in a public meeting in Washington that the white pine was doomed, that there was no help for it, that it could not be reproduced. In matters involving essential public policy, senators should be better informed.  At the very hour of his utterance white pine seed, grown from mature trees in Germany, was being used in this country to produce seedlings for use in our forest nurseries.  It is furthermore noteworthy that this imported white pine seed came from trees, or seeds, imported into Germany nearly a century ago from North America.  It is fair to say that the white pine is among the easiest of our forest trees to reproduce. Forests of white pine, grown from nursery sown seed, are now well advanced on the Biltmore estate in North Carolina.  The earliest plantation on the forest reserve at Mont Alto [this is in Pennsylvania] is now 15 feet high, and is in as thrifty a condition as any of natural growth.” (pp. 7-8)

As we see, by 1915, production was beginning to approach the needs of foresters, but they weren’t there yet. And in April 1916, in the magazine American Forestry (vol. 22), there is an advertisement published by Little Tree Farms of America (near Boston), for white pines, “The King of American Evergreens”,

“Use White Pine for screens, borders, avenue planting and otherwise beautifying an estate; for cutover lands; for sandy soils and other bare, unproductive, unsightly places; for worn out pastures; for lands useless for other purposes; for underplanting in shady places in woods where chestnut trees have died out. Plant groves of White Pine for restfulness.”

They charged $200 for a thousand trees, and $4.50 for ten of them. And so, beginning in 1912, after the Plant Quarantine Act, very few white pines were planted, and this remained the case for quite a few years thereafter, but it wasn’t long until domestic nursery production was rising to meet the needs of US planting.  And by 1919, white pines were being distributed, free of charge, by the Commissioner of Forestry of Pennsylvania, as is noted in Forest Leaves (published by the Pennsylvania Forestry Association), in February 1919. [“The stock available for free distribution is almost all three years old and includes white pine, red pine, Norway spruce, European larch, Arbor Vitae, and a limited quantity of Japanese larch, and white ash.”]

The white pine stand in Cresheim Creek is roughly a hundred years old, and now, perhaps, it is clear why that “roughly” becomes interesting. It is now 2012.  In October 2011, we cored a couple of trees in the white pine stand along Cresheim Creek (by “we” I mean John Vencius, Ned Barnard and me).  For those two trees, we got, respectively: ages of 95 +/- years (dbh [diameter at breast height]: 29.3 inches) and 80 +/- years (25.5″ dbh).  This puts the older one at right in the midst of the time when white pines were rarely planted, and right around the time when imports were banned. Coring of trees, like all endeavors scientific and otherwise, is not absolutely accurate – there is error associated with all measurements, and so we measure multiple times, and we measure multiple points, so that we can asymptote to reality.  Therefore, at this point, with so few data points, we can only roughly say when this stand was planted – about a hundred years ago.  And it leads us, or leads me at least, to ask some questions: Was this stand planted with seedlings imported from Germany? If so was it one of, if not the, last one planted in Philadelphia with imported seedlings?  Or was it planted with seedlings produced domestically?  If so, was it one of, if not the, first stands planted with domestically produced seedlings? I don’t know, and we don’t know, the answers to these questions, yet.  If we knew everything, then researchers would all be out of work , and so, fortunately, there are always questions to ask, and there always will be, as long as there’s people to ask them.  We’ll be looking at more of the trees in that stand, to see how old they are, and also looking for archival documentation of this stand’s planting, to see more closely when it was sown, to see on which side of the great divide of 1912 these plantings occurred.

There’s always questions to be asked, and often, too, there are answers to be had.  We’ll see what those answers are, as they arrive. There is a larger question, however, that arises from these trees, I think, and that question is – what is natural? This stand of white pines in Cresheim Creek sits in the midst of Philadelphia, one of the largest cities in North America, and if most people were to walk among these trees, they would see it as an inspiring piece of nature’s work that somehow survives the urban impacts around it.  After hearing that it is planted with a species of tree that is not native to Philadelphia, and that this stand was quite possibly planted with seedlings imported from thousands of miles and across an ocean away, and most certainly was planted with nursery grown seedlings from somewhere, and that it was quite likely planted for engineered erosion control, they might feel differently, might not feel that it’s natural. But these trees are here, and they are growing.  They were planted a hundred years ago, or so – before I was born, before my parents were born, they were here.  They’ll most likely be here long after I’m gone, too.  Birds fly among them, squirrels climb in their branches, people walk under them.  They’re seeding in offspring, seedlings coming up at their parents’ feet – being naturalized is in their nature.  Someone, or more likely, someones, put them there, but now they thrive and survive on their own, set into an area along a creek that was a major industrial site, but no longer is, in the midst of one of the largest cities in the country, in a city that is thoroughly carpeted with concrete, this lush green forest rises above carpets of its own leaves, and you wouldn’t know its nature unless you looked very closely, at which point you see that this stand has created a little world all its own, and does make us think that, in this world, there’s a lot of ways to be natural.

White pines of Cresheim Creek_map

Map by Nicole Wagner, graduate student in Geography and Planning, West Chester University, of the white pine stand along Cresheim Creek.

For more about trees of the Wissahickon watershed, see here: The white pines of Hermit Lane Hemlocks along the Wissahickon

The American chestnut

When William Penn arrived in the new world in 1682, he saw a land rich with natural resources, and the following year, when he wrote back to England, describing this wealth to Friends back home, central among the descriptions were those of the trees.  In a letter dated the 16th of August 1683, he writes:

“The trees of most note are the black walnut, cedar, cypress, chestnut, poplar, gumwood, hickory, sassafras, ash, beech, and oak of divers sorts, as red, white, and black, Spanish, chestnut, and swamp, the most durable of all; of all of which there is plenty for the use of man”

He goes on to write:

“The fruits that I find in the woods are the white and red mulberry, chestnuts, walnut, plums, strawberries, cranberries, huckleberries, and grapes of divers sorts”

(These extracts are from “A Letter from William Penn, Proprietary and Governor of Pennsylvania in America, to the Committee of the Free Society of Traders of that Province, residing in London,”)

What is the only plant that is mentioned twice?  It is the chestnut – the American chestnut (Castanea dentata), specifically.  This was a tree of such value that William Penn mentions it twice in his relatively brief letter (or ‘advertisement’ more accurately – he very much wanted people to come over and live in Pennsylvania, and so he was playing up the highlights for that cause, and so this truly was advertising) that he sent back home to England, at a time when correspondence was not as cheap as it is now, a time when every word would have been dear and measured.  Among the treasures of the new world, the chestnut shone brightly.

And through the decades, and even centuries, from William Penn’s time, the chestnut remained extraordinarily highly regarded – and it was more than just a useful tree, it was also beautiful, as this image (via the New York Public Library) from the early 19th century shows:

American Chestnut, from Francois Andre Michaux’s “North American Sylva”
(1810-1813)
Image via New York Public Library

This tree, the American chestnut, was extraordinarily valued for all it could produce, and was also extremely common.  Though estimates vary, at least a quarter, and most likely much more, perhaps up to and above two-thirds, of the trees of Pennsylvania were American chestnuts.  (NB: the American chestnut has been part of the eastern North American flora for about eight or nine thousand years or so, becoming a part of the mix shortly after oaks rose to prominence about ten or eleven thousand years ago; the oaks had in turn followed spruce/pine/birch dominated ecosystems which arrived about 13 -15,000 years ago, i.e, after the last glaciation had receded long enough to allow trees to recolonize the region; this set of timing estimations is based on palynological data, that is analysis of pollen from different strata under the ground, in such papers as M. A. Watts’ “Late Quaternary Vegetation of Central Appalachia and the New Jersey Coastal Plain” (Ecological Monographs, 49 (4): pp. 427-469 (1979) and Zhao et al’s “Hemlock (Tsuga canadensis) declines at 9800 and 5300 cal. yr BP caused by Holocene climatic shifts in northeastern North America” (The Holocene 20: 877 [2010]))

The fruits, the chestnuts that is, were forefront among the valuable resources to be garnered from this plant.  As described by William Darlington in his 1837 Flora Cestrica: “The fruit of our native tree is smaller, and much sweeter, than that of the foreign one…”; and in his 1826 Florula Cestrica, he notes that “The treat which the nuts afford, for our tables, is familiarly known to everyone.”  And from the eminent botanist Francois Michaux’s “North American Sylva”. v. 3, 1810-1813 (translation 1819, Hillhouse):

“The fruit is spherical, covered with fine prickles, and stored with two dark brown seeds or nuts, about as large as the end of the finger, convex on one side, flattened on the other, and coated round the extremity with whitish down. They are smaller and sweeter than the wild chesnuts of Europe, and are sold in the markets of New York, Philadelphia and Baltimore.”

These nuts were of extremely high quality, and economic value, too – people would go out to parks and forests to collect them by the basket and the bushel – sometimes they would eat them, other times they would sell them, but every year they would gather them.  And other animals, in addition to humans, ate chestnuts, too – they would have been a regular supply of high energy (they are quite fatty) food for squirrels, for deer, for passenger pigeons – for all kinds of animals that need such food in the fall.  Yes, these animals would have also eaten acorns, but oak trees, from which those acorns fall, yield nuts irregularly – some years they are plentiful (in “mast years”), and in others they are not.  And so the regular supply of the chestnuts would have regularly provisioned, at a steadier pace than the oaks, these animals – animals which, in turn, would have regularly provisioned the people who ate those animals.

And there were other values to be derived from the chestnut – Michaux notes that “The wood is strong, elastic, and capable of enduring the succession of dryness and moisture” and so it was valuable for posts, rails, and shingles.

And, though its wood was not directly used for fuel (because it doesn’t burn very well), it was excellent for charcoal production.  Michaux, writing as to why people should grow more chestnut trees for charcoal:

“Besides the inducement of private gain, this measure would be attended with public benefit, by the economy of fuel, which is daily becoming scarcer and more costly”

(above quote from Francois Michaux’s “North American Sylva”. v. 3, 1810-1813 [translation 1819, Hillhouse])

Even two hundred years ago, there was concern about scarcity of energy sources, and the chestnut was seen as one of the feedstock solutions to that everpresent problem.  Chestnut is especially useful for charcoal because it can be coppiced – that is, after the top part of the tree is cut back, suckers will grow up from the root crown, making new trunks where the old one had been cut off.  This could be done every sixteen years or so, according to Michaux, to make for a renewable source of wood for coal production.

But the utility of the chestnut didn’t end with food, fuel, and housing – it even extended to clothing.  Not directly, of course – the colonists and early Americans weren’t going around dressed like Great Birnam Wood – but the bark could be, and was, used to tan leather.  Fresh leather is not, as you might expect, ready to wear.  It needs to be treated to prevent it from rotting – that is, it needs to be tanned.  And the bark of chestnut trees are rich in tannins, chemicals that interact with the proteins in leather to alter them into a form that is less digestible to microbes (that is, it makes them resistant to rotting).  And so, an early method of tanning was to take the bark of a tree rich in tannins, such as the chestnut (hemlock bark was also commonly used – more commonly than the chestnut, actually), toss that bark into a pit filled with water, let the tannins leach out of the bark and into the water, and then toss the leather into that solution, and then wait until the leather was tanned and resistant to rot, and, then… pret a porter!

This tree, the chestnut, was the five and dime of early America – the fruits were good to eat, even better than their counterparts from Europe – the wood could be used for making fences and roofs and rails – the wood could also be made into charcoal to serve evergrowing energy needs – the bark could be used for tanning leather.  It was the one stop shop for an extensive list of a colonist’s or early American’s household needs, wants, and desires.  And it was everywhere, like a Woolworth’s on every corner.

Now, however, it is not.  So what happened?

In 1904, the chestnut blight arrived.  First discovered in New York City, it rapidly spread throughout the forests of eastern North America – where ever the American chestnut was, the blight was soon to follow, as is illustrated in the following map:

“Map showing the rate at which chestnut blight spread over the Eastern United States. The dated lines show the extent of the heavy infection at the time indicated.”
From: Flippo Gravatt, 1949: Chestnut blight in Asia and North America. Unasylva, 3:2–7

The above map, and the entire text of the paper associated with it, is available here

It’s not totally clear how this disease arrived initially – it is originally from Asia, and could have come in on material imported from there to the US, but however it got here, it arrived, and was first reported from the Bronx Zoo in 1904, and within a few years it had already spread to Connecticut, to Massachusetts, to Maryland – its distribution was rapidly fanning out, like mold on an orange.

The causative agent of the blight was isolated and described shortly after the disease was discovered – William Murrill, a New York mycologist, did this in 1905, and named the disease Endothia parasitica (though we now call it Cryphonectria parasitica), but just knowing what it was, was not enough.  The disease still spread.

About ten years later, Frank Meyer, the Dutch plant explorer who worked for the US Department of Agriculture collecting plants in Asia, found this fungus in China, and then a bit later in Japan – it was found to live reasonably benignly with the chestnut species that live there, in Asia, and the geographic origin of the blight was now known.  But just knowing where it was from was not enough.  The disease still spread.

As the blight moved onward, the chestnuts died back – and other trees grew up to take their place.  This was documented in work done by, among others, Joseph Illick (Chief of Information of the Pennsylvania Department of Forest and Waters), and also other foresters such as C. F. Korstian and Paul W. Stickel, who wrote about their research in a 1927 article, “The natural replacement of blight-killed chestnut in the hardwood forests of the northeast”.  The title alone tells you the impact that Cryphonectria parasitica had.

As these researcher saw the blight remove the chestnut from the forests, they, as foresters, needed to see what trees would grow up to replace this enormously valuable tree.  Would they be replaced by class 1 desirable species?  Would they be replaced by class 3 undesirable species?  Or by species inbetween?

To find this out, they went out and looked to see what was coming in as the chestnut was going out.  And they found that the chestnuts were being replaced mostly by oaks, such as the red, white and black oaks, among others, including the chestnut oak, and also by some other kinds of trees – hickory, white ash, sugar maple, sweet (black) birch.  These trees were, mostly, what these foresters considered to be “Class 1 – Desirable species”, useful for forest products – perhaps not quite to the level of the chestnut, but useful still, for products useful to people.  And so, while the chestnut would no longer be what it once was, the forest would still be there, as would the foresters.

The chestnut was a tree that, as late as 1907, Samuel B. Green would write in his Principles of American Forestry (a book I stumbled across while perusing the stacks at the library of the Academy of Natural Sciences) was “One of the most beautiful of our forest trees.  Prefers a rich, deep soil.  A rapid grower and highly esteemed ornamental tree. Does well under cultivation.”  Shortly thereafter, this was no longer to be.

This is not to say it wholly disappeared – its wood’s durability, as noted above from Michaux, made it so that the wood lasted for decades lying in the forest, even after the trees had fallen.  And its ability to grow from suckers has made it so that it persists even to this day – suckers grow up, die back from the blight, and suckers arise once again – never getting to the size of a full size tree, but surviving nonetheless.

But the chestnut was no longer the dominant tree of the eastern North American forests.

And it wasn’t just in the woods that the chestnut was fading away – this is also a tree that had been widely planted – a tree of such value certainly would not have escaped cultivation, and it was commonly planted and grown, and a pretty inexpensive tree to buy, too.

As a visit to the McLean Library at the Pennsylvania Horticultural Society, and lots of help from Janet Evans, the librarian at the McLean, lets us know – the chestnut was cheap and plentiful in the horticultural trade, as we see from its history in nursery catalogs.

In the catalogs of the Meehan’s Nursery, one of the largest nurseries of eastern North America of the late 19th and early 20th centuries, American chestnut trees were listed from this firm’s earliest days –

In 1858, they sold for 50 cents a piece – and in the Fall 1880 catalog, they went for 10 cents a piece, 50 cents for ten, and $3 per hundred for 1 to 2 footers, and 50 cents a piece for 6 footers – while other trees might have been as cheap, none were sold for less, attesting to the ease of propagation and volume of sale of this plant.  This continues onwards as the 19th century unfurled – in the spring of 1885 they were 50 cents a piece – the cheapest of the chestnuts listed (chinqapin, spanish, and japanese chestnuts were also listed).  In 1893 and in 1895 its price and rank were still the same.  Also, these 1890s  catalogs note: “This leads all the sorts in the quality of its nuts and its valuable timber” – the chestnut was not just some easy to grow tree, it was also supremely sublime as to the value it provided with respect to food and shelter.

It was also valued for its horticultural qualities, especially for a people who were more and more buying houses with yards to be filled with shade trees, and filled as soon as possible, hence the advertisement in the 1897/1898 Meehan’s catalog, saying of the chestnut: “It is a very rapid grower and should be given ample room.”

And onwards on – in 1900 the listing includes a mention of “Our native wild Chestnut, so well known and appreciated” – this tree appealed to patriotism as well as its many other valuable qualities.  It was an American tree – Longfellow wrote about how “Under a spreading chestnut-tree / The village smithy stands.”  For the homeowner at the turn towards the 20th century, they most likely would not have been a smith, except perhaps by name, but they quite likely would have been wanting to harken towards the nationalistic pride and small town imaginings to which a native American plant would have given rise.

The American chestnut continues on in the Meehan’s catalog, into the 20th century it went, setting sale just as it had in the 19th – and in the 1905 catalog, after the chestnut blight had been discovered in New York in 1904, this disease is not mentioned, they did not know what was to come.

Before I continue on, I would like to say that crucial information in the following paragraphs was supplied by Marie Long of the LuEsther T. Mertz Library of the New York Botanical Garden; and Marty Schlabach, of the Mann Library (Cornell) in Ithaca, NY; and Lynn Stanko of the National Agricultural Library (USDA), in Washington, DC; and Kathy Allen, of the University of Minnesota’s Anderson Horticultural Library – and I was able to reach out to such talented and knowledgeable people because of Janet Evans, who made this research possible.

The loss of the American chestnut in the horticultural trade was sudden.  The last time it is listed by Meehan’s nursery is in 1911, in the fall catalog.  And then, with one bit of fade out, it is gone:

“In the Meehan’s Plant Book for 1912.  In the section on Deciduous Trees, Castanea dentata is not listed, however, in the index of that same publication, Castanea dentata is listed but asterisked with the following comment:  ‘These plants, though not described in this book, we have in stock.  Write us for descriptions, prices, etc.’ ” (Lynn Stanko, NAL)

It is not in the 1912, 1913, or 1914 catalogs – it was sold no more.

How did this happen so suddenly?  I was able to ask and answer this question quickly and efficiently because of access to great libraries – the McLean Library at PHS, as mentioned above, and also the library of the Academy of Natural Sciences with guidance, as is so often needed, by skilled librarians and archivists.

In the Academy’s collections I found Bulletin No. 1 of the Pennsylvania Chestnut Tree Blight Commission (an organization that was conveniently located on Chestnut Street, in downtown Philadelphia, by the way), which came out in October 1912.  This first bulletin was titled “The Chestnut Blight Disease – means of identification, remedies suggested and need of co-operation to control and eradicate the blight.”  It covered just what it promised and gives an overview of the chestnut problem, up to that point in time.

So what happened in 1911 that Meehan’s so suddenly stopped selling these trees?  As the above mentioned bulletin notes:

“Pennsylvania is the first State to attempt systematically to check the progress of the blight. On June 11, 1911, Governor Tener signed an Act which was passed by unanimous vote of both houses of the Pennsylvania Legislature.”

And what was in that legislation that affected Meehan’s nursery?

“A quarantine on chestnut stock was declared which prohibits the shipment of nursery stock not bearing the Commission’s tag of inspection. This certificate means that the stock has been inspected in the nursery rows, and again after it has been dug. Diseased trees are destroyed, and those which are apparently healthy are immersed for several minutes in Bordeaux mixture or lime-sulphur wash [note: these are both antifungal treatments], and are then tagged by an inspector. Only a comparatively small amount of chestnut stock was shipped by the nurseries during the last fall [i.e., fall of 1911].”

Whether this legislation affected Meehan’s because their stock was infected, or if it just simply became too expensive to treat and inspect (and to take the time to do so) each plant, and to destroy suspect stock, I do not know.  But with a sudden stop, and barely an audible gasp, the American chestnut was gone from Meehan’s catalog, never to return.

There are still some chestnuts in Philadelphia.  I don’t see them as often here as I did in New England (for example, the Hapgood Wright Town Forest, in Concord, Massachusetts has loads of them – small and scrubby and infected with the blight, but there nonetheless).  I haven’t seen a single one along Cresheim Creek, a creek that runs into the Wissahickon, and divides Chestnut Hill from Mt. Airy, though I know they were there historically.  We did see one up by Forbidden Drive recently, just below Bell’s Mill Road – a scraggly shrub that Marion Homes pointed out on a Philadelphia Botanical Club visit there a few weeks ago.  And there are some that are planted here in Philadelphia – one is at Bartram’s Garden, and there are a couple at Independence Square and another at Washington Square, that Susan Edens has shown me.

But it is not the dominant tree it once was, not even close.

A few years ago, I was walking through the National Gallery, in Washington, DC, ambling around the rooms with the 19th century American paintings.  Among the Morans and the Coles and the Cropseys, was this painting, October, by William Trost Richards.  I was standing there looking at it, thinking about what plants were in that scene, and looking at the large tree on the right side of the painting – its leaves look like a beech, a tree that’s commonly seen in the woods of eastern North America, but the bark of this painted tree is extremely different from that of the beech, and so that clearly was not what this was.  I was looking at it, and looking and looking and I really just could not think of what it was – I’m reasonably familiar with the trees of the eastern forests, but this one had me stumped, so to speak.

Until I realized that it was a chestnut.  An American chestnut – a tree I had never seen before at this enormous size, or even close to it.  And I also realized that this was a scene I would never see.  I’ve been in chestnut groves in Italy, and they are majestic.  I have seen many small trees and suckers of the American chestnut, especially when I was up in New England.  But something I will never see, except in paintings, or in very old photographs, is a full grown Castanea dentata in an American forest.  It is gone, times have changed – oaks, and other kinds of trees, have filled in the space laid open by the passing of the chestnut, and so the forest remains.  But the chestnut, as the lord of the forest, does not.   It remains, yes, as a scrabbling shrub or spindly tree, but its dominance is gone, and in my lifetime, or even the lifetime of anyone born today, it will not return to its former heights.  Its place left open for others to take it, the chestnut has become a minor piece of the current sylvic puzzle – the forest remains but the trees change, and the chestnut has lost its dominance.  But the forest remains.

To read about some other trees, see here:

The saucer magnolia

London planes and American sycamores

American elms

“Penn treaty” elms

The Callery pear

The Caucasian zelkova

Paulownia tomentosa, the empress tree

The sophora

Fringe tree


					

American elms

There are elms fruiting now.  If, as you walk around the city, you look down at the pavement, or the grass, or the asphalt, you’ll see at some places papery little disks, generally less than an inch across, often quite a bit smaller – some are ciliate (they have fine hairy fringes, that is), while others have entire margins (that is, their edges are unfringed), but pretty much all of them, if the tree they come from has any hope of passing on its genes to progeny, have a seed in there.  Some have their seeds at dead center, while for others they’re positioned a bit towards the apex of the fruit, but all of them, unless their parent tree was unfortunately barren, have a seed.

These fruits are called samaras.  Samaras are fruits with wings – if you look at a maple tree, at some of them about now, the red maples for example, you’ll see another kind of samara, different from those of the elm, with these ones, those of the the maples, making the helicopters or Pinocchio noses you probably played with as a kid.  The maple samaras aren’t in the rounded and somewhat symmetrical form of the elm samara, their wing, the wing of the maple fruit, is extended in one direction, on one side of the seed, and then two are joined together to make the kind of samara that spins as it lofts towards the ground or as it is carried away to be dispersed by the wind, to new places where the seed might grow into a tree (or not).  For the maples, their wings extending outwards make for simple little machines that cause them to spin as they fly away.

For the elms, they are different.  Their samaras don’t make helicopters, their samaras are in a circular or somewhat elliptical shape, some having a notch towards the top, but all having generally a saucer shape, though sometimes uncircled and stretched in one direction to make, I guess, perhaps more of a tureen saucer than one for coffee cups, but saucer shaped nonetheless – and those samaras are all over the place now, falling to the ground beneath the elms’ spreading branches.

The ciliate samaras, the ones that are densely fringed – these rounded shaggy-margined, papery, less-than-an-inch roughly-ovals, the ones you see littering the street that look like that, these belong to the American elm.

The American elm used to be the street tree, the street tree.   Planted in long rows, in lines up and down main streets and smaller streets and all kinds of sized streets, in towns and cities across America, these plantings, they made for a beautiful effect that was somewhat architectural – the branches of the elms from opposite sidewalks meeting in the middle, forming a broad arching ceiling over the street, a covering under which horses, carriages and then ultimately automobiles traveled, and along which people walked in the shade in the summertime and under naked branches in the winter.  This was the tree of America’s streets.

The American elm was also treasured for open plantings.  With its broadly spreading branches zigzagging around and angling outward like the sides of an opening vase, this elm made for a striking shape, standing tall in a yard or park, or in the National Mall in Washington, DC, or in Harvard Yard in Cambridge, MA, or in Rittenhouse Square in Philadelphia, PA, and in places of prominence elsewhere as well.

Put simply, and to quote Andrew Jackson Downing’s Treatise on the Theory and Practice of Landscape Gardening (1841), “Let us now claim for the elm the epithets graceful and elegant.”

The elm was everywhere.  And it had always been common here.  Peter Kalm, the Scandinavian botanist who explored the new world in the late 1740s, writes of this tree as being found throughout the area in and around Philadelphia and New Jersey:

“June the 28th [1749].  The American Elm, (Ulmus Americana Linn.) grows in abundance, in the forests hereabouts.”

And back then as it is now, they flowered about this time of the year, late March:

“March the 21st [1749].  The red maple (Acer rubrum) and the American elm (Ulmus Americana) began to flower at present; and some of the latter were already in full blossom.”

[the above quotes are from John Reinhold Forster’s translation of Kalm’s “Travels into North America”, published in 1771]

And, in the city of Philadelphia, in what is now Independence Square, but was at the time called the State House Square, in the 1780s Samuel Vaughan, the man responsible for designing that square’s landscape, just after the American Revolution, was given a hundred American elms by Captain George Morgan of Princeton.  Vaughan planted them in a double allee along the main north-south path, and the founding fathers of the United States would have walked among them as they worked and lived, in their day to day lives and quotidian workdays that created much of what we live within today.

And so, from the early days of European colonization through to the constructions of the cities and towns of 20th century America, the elm was everywhere.

Then, in 1929, the Dutch elm disease arrived.  First found in Ohio, within a decade it had spread to Indiana, to Maryland, to Virginia – as far as eastern Connecticut and New York City, it had spread hundreds of miles within just ten years, according to Joseph Horace Faull, professor of forest pathology at Harvard (he spent most of his time among the trees at the Arnold Arboretum in Boston), who wrote about and studied this disease, in the 1930s.

Throughout the middle and the latter part of the 20th century, Dutch elm disease spread and spread, wiping out graceful elm plantings in yards and parks and open greens, and caving in the arched vaults formed by elms’ branches across the streets of America. The distribution of the disease rapidly became coterminous with that of susceptible elms – slippery elms (Ulmus rubra), another elm native to North America, can also catch the disease, as can the English elms (Ulmus procera) that had come over to the US from Europe.

A fungus is the causative agent of the Dutch elm disease, well two fungi, actually – Ophiostoma ulmi and Ophiostoma novo-ulmiOphiostoma ulmi, arriving in the US in the early half of the 20th century, caused the first ranging of the disease, and then the more aggressive Ophiostoma novo-ulmi came on to replace that original colonizer in later years.

The fungus spreads by two routes – either via bark beetles, who carry the fungus with them as they go from tree to tree, diving into the bark to live and breed, or via root grafts.  What are root grafts?  They’re pretty much what they sound like – when elm trees grow near to each other, as you might expect, their respective roots can come into contact.  When this happens, the roots can fuse, combining together, even down to the plant’s vascular system.  This allows the fungus to spread because it can travel through this vascular system, the plant’s water transport system, the xylem.  Though the Dutch elm disease commonly spends much of its life growing as filamentous strands (=hyphae), it can also transition to a single celled form, which we call a yeast (to a mycologist, a single celled fungus is a yeast), allowing it to cruise along the xylem like a vascular highway, up and down the tree, unimpeded by bark or air, through shoots or through roots.

And so, you can imagine what this meant for those long majestic rows of elms that were planted cheek by jowl next to each other along the streets of America.  If one instance of a bark beetle arriving brought the fungus with it, the yeast of the Dutch elm disease then rapidly went from tree to tree, by the roots subterreanean vascular system, until the allee fell like a series of arboreal dominoes.

And why exactly did these trees fall?  What is it about this disease that kills the trees?  Well, imagine if you had fungi growing in your vascular system – it would become blocked up, thereby preventing the flow of nutrients to where they need to be.  The same things happen to trees infected with this pathogen – the vascular system is blocked, causing the trees to present the diagnostic early symptom of the disease, called “flagging”, where entire branches in the tree canopy exhibit drooping leaves that yellow and brown, which is then generally followed, ultimately, by the death of the tree.

There are interventions available – removal of diseased parts, insecticides to get rid of the bark beetle, fungicides to attack the fungus, cutting of the roots to inhibit spread underground – but these are intensive and require resources, both financial and in terms of labor spent on these efforts, and so replacement of the elm is generally the more viable option.

And so, through the latter part of the 20th century, American elms have become a reduced part of our urban tree community.  But they’re still there.

There are quite a few American elms in Philadelphia – there’s a large healthy one in Dickinson Square, at Tasker and Moyamensing, and there’s one in the southeast corner of Rittenhouse Square in center city, and another at the northeast corner of 22nd and Chestnut, in front of what used to be a Swedenborgian Church, and right down the street from the College of Physicians.  And if you look in the Kaskey Memorial Garden on Penn campus in west Philadelphia, or on the grounds of Friends Hospital up in Frankford, or in front of what was Lankenau Hospital, on Corinthian Avenue just south of Girard College in north Philadelphia, if you look in these places you’ll find more of the American elms that grow here in Philadelphia.  And we have English elms, too – seven enormous ones at the Woodlands Cemetery right near Penn (two of which date to William Hamilton’s time; in 1921 those two were, respectively, 10′ 1″ and 10′ 3″ around), and at Marconi Square in south Philadelphia, right along Broad Street, on the west side of Broad, there’s one with a trunk over five feet across. (and for an interesting historical record: in John Watson’s Annals of Philadelphia and Pennsylvania in the Olden Time (1899, “enlarged, with many revisions and additions, by Willis P. Hazard”), p. 373, vol. 3, he notes after a brief mention of the balloon riot that occurred in 1819 at “Vauxhall Theater, north-east corner of Walnut and Broad streets”, that “The elm that stands on Walnut street, overhanging the street, was on old tree then.” [Vauxhall was also called Vaux Hall Gardens, and had a very open parklike aspect to it, in 1819; in the 1890s, there was still a fair bit of open space in that lot, as one can see from the 1895 map here, but by 1910 it was all pretty well covered over and the elm would have been gone])

And at Independence Hall, right behind it there, along with the enormous London planes, and nearby to some little chestnuts and not far from a Franklinia, and with dozens, hundreds, or thousands of people walking under it every day, is an enormous American elm, rising high above the square.  There are other American elms there too, five in all – in that smallish square, there are multiple elms.  One, planted in 2004, is a ‘Princeton’ cultivar, a variety that, while known and planted prior to the Dutch elm disease’s incursion into America, ended up being able to co-exist with both species of Ophiostoma and therefore ended up being planted more widely, quite widely actually.  This cultivar grows well, and the example of it that is in back of Independence Hall is strong and healthy, growing  alongside its older relative that towers above the square.  These stand as a reminder of a time when American elms were the American tree, and they are the right plant to have at this historic site – trees deep in history, that are still growing tall, even though organisms that were new to them have inalterably changed their presence in the landscape, the elms stand, and grow.

To read more about elms, including Penn Treaty elms, see here;

https://growinghistory.wordpress.com/2012/02/28/some-history-of-historic-plants/