The Urbanization of the Eastern Gray Squirrel in the United States

The eastern gray squirrel (Sciurus carolinensis) is ubiquitous in Philadelphia today, and in many other cities as well.  However, this was not always the case.

To read more about these little mammals, and how, when and why they came to be so citified, see here:

The entire paper mentioned in the linked-to article above is here:

And for a bit more on squirrels in Philadelphia, see within this page:

and this one:

The white pines of Hermit Lane

If you take a turn onto East Hermit Lane, just off of Henry Avenue after Henry Ave has crossed over going west from East Falls, and go down towards the site of the Kelpius cave, you’ll see on your left, on the east side of East Hermit Lane, a large stand of white pines.  Some of them are quite large, over two feet across, and with a canopy dozens of feet above the ground, they tower above the house that’s there.  Underneath them there is a ground layer with pokeweed, and jumpseed, and enchanter’s nightshade, and many other herbaceous plants, and there are also beeches and birches coming up in the understory.  But the white pines dominate, in terms of the aspect of the stand, and in terms of sheer numbers and size.

This stand is strikingly similar to one along Cresheim Creek, and based on their size, they (the ones along Hermit Lane, that is) were quite likely planted at a similar time as were the ones along Cresheim, and as is clear from the picture below, the Hermit Lane pines were there in 1931 which provides further evidence as to their age, and solidly provides an upper bound (of 1931) to their date of planting.

From the Library Company of Philadelphia Digital Collections:

From the Library Company of Philadelphia Digital Collections:
Aero Service Corporation, photographer; 1931  [The white pines are on the left side of the photograph, roughly midway between top and bottom of the picture, directly to the left of the Henry Avenue Bridge, which was being built at that time]

These trees along East Hermit Lane, however, while some of them are on a slope, most of them are not, and the plantings on the level grade are much denser in the above picture than the ones on the percent grade (this difference is also noticeable when you walk among them today), and so, different from the white pines of Cresheim Creek, the Hermit Lane pines probably weren’t planted for erosion control, but perhaps more broadly as part of reforestation efforts of a century ago, to bring back the sylva to Pennsylvania.

As was noted by John M. Fogg, Jr in his “Annotated checklist of plants of the Wissahickon Valley”, published in Bartonia (vol. 59) in 1996: “Although white pines may originally have occurred in the valley, the trees growing here today are the result of recent plantings.  A fine grove exists along Hermit Lane near Hermit Street.”

If we look at a map from 1895, we see that this locale (where the white pines are) was privately owned at that time, and though, as we see from a map of 1910, the neighboring lots were part of Fairmount Park by the earliest parts of the 20th century, this particular site (again, where the white pines are) was not.  If we assume that these trees were part of park plantings, and not plantings of private property, then this gives a lower bound of 1910 for the year of planting for these trees (given that the property was not part of the park in 1910, as indicated by the maps linked to above), thereby further supporting the argument that these trees date to the vicinity of about a hundred years, again, much like the white pines of Cresheim Creek.  And if we look again at that 1931 aerial, above, we see that the stand extends across the path that divides what was private property in 1910 from what was park property at that time. This further implies that the planting was associated with the park, and therefore would postdate the time when that lot became part of the park.

If we look at an aerial photo from 1937, then we see that the stand of white pines is visible, and quite prominent – densely packed in, and of a reasonably appropriate size for stand in its mid-twenties.  The second portion across the path is still there, visible in that 1937 photo, too.  And if we look at aerials from 1942 or 1957, we see that this stand of white pines is clearly apparent there, along with the portion to the southwest, across the path (it is no longer there today).  [to browse more aerial photos, see here: ]

Something that we see as we look at these aerials across the 1930s to the 1940s to the 1950s, in addition to the stand itself, is also the wooded areas around it and nearby.  And from this we see that as the pines that were planted there grew, that there were wooded areas surrounding them, and they were growing too, until that landscape today yields an appearance of continuity – it is all “the woods”, even if some parts of them look a bit different from one another.  And if we walk there today, it can seem like the woods have always been there, in these large expanses, and that they are “natural”, in the sense of not having been made by people, that they just kind of got there on their own and that they keep on going and growing, all on their own.  After a century or so, it all just looks like woods, and the kind of woods that we might imagine has always been here. [NB: we heard Pine Warblers here on the 10th and the 13th of April, 2014 – and so one might say that the birds see the pines, too [note that Pine Warblers are not listed as being in Cresheim Creek, where there’s another thick white pine stand, in J. C. Tracy’s paper “the Breeding Birds of the Cresheim Valley in Philadelphia, 1942“, published in Cassinia]; I’ll note also that at this time (the 13th of April), along the Wissahickon, near and downstream from the Henry Ave bridge, that bloodroot and trout lily and spring beauty were all in flower and that Podophyllum was beginning to leaf out, too]

If we look a a photo from 1911, of the Lotus Inn, we see that there were a fair number of trees down in the ravine:

The above photo was taken a bit downstream from the Walnut Lane Bridge; it’s where the Blue Stone Bridge is now; that bridge was the continuation of the road you see there in that photo – it’s now the trail that leads up to the Henry Avenue golf course (it used to be Rittenhouse Lane).  That is, it’s just a bit away from where the white pine stand of Hermit Lane is now. [I’ll note also that it looks like there’s hemlocks there, too]

More broadly, looking around Philadelphia today, along the Wissahickon or the Pennypack, or in the wooded areas of West Fairmount Park or Juniata Park, or throughout so many of the many other parkland areas currently in Philadelphia, we see forests, and it can seem some times as though that it how it has always been.

Certainly, when William Penn arrived here in the 17th century there were woods woods woods and more woods, filled with all kinds of trees.  But by the 20th century, these had been cut over, multiple times (see page 39, here, for more about this), and also just prior to and at that time (the late 19th and into the 20th century, that is) was a period of incredibly extensive development across Philadelphia, and therefore wooded areas were being rapidly cleared to accommodate housing, and also businesses and industry – the economic drivers of a thriving city.   This period was an intense time for this – there was roughly a doubling of the population of Philadelphia between the 1850s and 1890 (according to US Census data), when we went from about a half a million to about a million people, and then the population roughly doubled again, until we hit about two million people in the mid-20th century, and one need not imagine the impact this would have on the woods, this massive population expansion.  We can also see this expansion of urbanization in the reduction of farms and farmland here – we go from 824 farms in Philadelphia in 1910, to 423 in 1920, to 381 in 1925 (data from the 1925 Census of Agriculture), which represented a reduction in farm acres in Philadelphia from 30,488 acres, to 17,408 acres, to 15,971 acres at each of those steps (Philadelphia’s total land acreage is about 82,000). By the 1950s, this had declined yet more, to 76 farms (5,024 acres) in 1954, and 53 (3,465 acres) in 1959; as of the latest census of ag, in 2007 there were 17 farms comprising a total of 262 acres.  (for more historical ag census data, see here:, and for current and more recent:; specifically for Pennsylvania:,_Chapter_2_County_Level/Pennsylvania/; additionally, in 1911 there were 1,474 license issued to “farmers”, according to the Annual Report of the Bureau for City Property for the year 1911).  Transportation affected this as well – farms could move out  of cities because of improved transportation (e.g, train lines), which could move food quickly across long distances (and with the advent of the refrigerated rail car in the 1890s, this adds in to the calculation as well).  Also, in the 20th century, with the shift from horses to cars for transportation, the decrease in the horse population numbers would have meant a reduced need for hayfields, and so as fewer horses were fed, farmland (for hay, in this case) would have had less of an economic simulus to stay open. (for an article on horses and cities, see: American Heritage Magazine, October 1971)

At the height of our deforestation rate, in the mid-19th century, a wooded site in our region would be cut about every 25 years (for a 4% (that is, 1/25, or one out of every twenty-five years) deforestation rate).  These woods that were being trimmed on the scale of decades were or had been cut to clear land for development, and for farmland, and to build houses (and for other lumber needs, like furniture or cabinets and what-have-you), and also for firewood, wood being the dominant energy source in the US pretty much through to the end of the 19th century, as can be seen in figure one, here; stoves also had an impact, as can be read about in “Forest Conservation and Stove Inventors: 1789-1850” [by William Hoglund, 1962]), and so it’s not like there would have been a single episode of cutting at a site as land was cleared and houses were built from those trees that were cut, and then everything then would have commenced back to growing into woods again, but deforestation was a continuous local process at that time, due to energy needs, as well. (e.g., as the use of coal increased, the cutting of wood for fuel would have decreased, thereby increasing forestation) [They were also cut for other reasons, even amidst revolution, as John Thomson Faris relates in his 1932 Old gardens in and about Philadelphia and those who made them: ‘…in 1782, the Corporation of Philadelphia ordered that all trees in the streets of the city be cut down, because “they obstructed the prospect and passage through the public streets, lanes, and alleys,…disturbed the water-courses and foot-ways by the extending and increasing of the roots.”  Then it was felt that they were apt to “extend fire and obstruct the operation of the fire engineers.”  Then, with rare humor, the additional indictment was given: “They were not affected to the government because they remained with the enemy when they had possession of the city!” ‘ …. Faris goes on to write that “Fortunately the strange law was repealed in season to save some of the trees that were the glory of the streets of the city.”]

By the late 19th century, the deforestation rate had slowed a bit, to about 2%, but that still means we’d expect stands to be at most about 50 years old at that time, in the late 19th and early 20th century, which is the time when we see the oldest portions of the lands that are now forested in Fairmount Park becoming the natural areas that we now know them as.

That is to say that Fairmount Park was still quite young, by arboreal standards, as the 20th century arrived and moved forward – the oldest parts of it were on the order of a half century old at that time (dating to roughly the mid-19th century, that is), and many large parts were still coming to the city as the 20th century rolled on (for example, like the Pennypack, whose land starts being acquired by the city in 1905, and of course the site upon which the Hermit Lane pines now stand comes to the city around this time), and so the woods of Fairmount Park that we see now, filled with enormous tulip poplars and oaks and pines, and hemlocks, too, would have been pretty young at that time, and nowhere near as full as what we see today. 

I’m not aware of any stands in Philadelphia that are older than 100 to 150 years old, and this is pretty well in line with the historical data outlined above.  This is not to say that there aren’t individual trees that are older than that, as we know that there certainly are ones much older than this (e.g, in Hunting Park), or even some groupings of older trees (e.g, if you go along the rocky hilltop trail along the Wissahickon, just north from the Henry Ave. Bridge, there’s some wonderfully old chestnut oaks growing among the rocks overlooking the Wissahickon there that, based on their size, quite clearly predate the late 19th century), but I’m not aware of any substantial stands of trees in Philadelphia that predate the late 19th century.

And so we see in the first half of the 20th century a low of the areal extent of the forestation of Philadelphia – the woods had been cut over multiple times by then, and older stands that might have been found in less populated areas, perhaps distant out in the far northeast, or way out in the wilds of west Philadelphia, both dry and wet, were being cut down for the development that accommodated our growing population, and the current grandeur of Fairmount Park was still a young sylva at the time, not yet grown to the size that we see now.

In the 1930s especially, it appears, Philadelphia had few forested areas – development had extended to parts of city that still had wooded spots, and Fairmount Park had not yet become the well forested agglomeration of sites that we know today.  Though it can seem difficult today to believe that our green city was once so unwooded, an illustrative anecdote of this is provided in Richard Miller’s paper, “the Breeding Birds of Philadelphia”, in volume 51, number 7 of the Oologist (“for the student of birds, their nests, and eggs”), published in 1933, where he notes of the American Crow that it is “Common, but slowly decreasing, due chiefly to destruction of woods.”  (I also note that the Red-Bellied Woodpecker, a bird of forests and woodlands, is not listed in Miller’s paper – this is a bird that I commonly see now, along the Wissahickon, and elsewhere (e.g, at Bartram’s Garden, on the 5th of April 2013), which calls to the increase of trees in Philadelphia, I note; this is a bird whose range has expanded northward generally in the past decades, I also note; NB: notes are good).

Nowadays, so far as I am aware, no one fears for the crows due to lack of woods, and in this we can see the change from then to now – today there are wooded areas throughout the city, from Cobbs to the Poquessing, and so many places in between, where there are not just trees, but forests, and woodlands.  Our landscape has changed drastically from a century ago – the woods we see now have grown since then, and what were once open areas are now wooded.  Of course, the opposite has also occurred – what were once wooded areas now are not, and are now populated by buildings or streets or mown parks (sometimes this happened with quite a bit of opposition, as the fight over “Sherwood Forest” prior to it being cleared illustrates), and so it’s not like the woods have all grown up everywhere throughout Philadelphia, but as those wooded areas were being cleared, elsewhere parklands grew, and weren’t then cut again to clear the land, or for timber and fuel, and so we see this striking change throughout the landscape, from a hundred years ago to today.

All of this change might make one wonder about ticks, for example Ixodes scapularis, the black legged tick; this species was named and described by Thomas Say, and that was done in the Journal of the Academy of Natural Sciences of Philadelphia (Vol. 2, 1821: pp. 59-83 – thanks to Ken Frank for pointing this out to me, by the way).  Say mentions of this species: “Rather common in forests, and frequently found attached to different animals.”

There also were differences in wetlands, between now and a hundred years ago, as is indicated by the inclusion of Typha angustifolia and “Phragmites Phragmites” (i.e., Phragmites communis), in Thomas C. Porter’s “Rare Plants of Southeastern Pennsylvania”, which is in the Botany Libraries at Harvard (it has a publication date of “March, 1900”).  These wetland plants are quite common in Philadelphia now.  An indicator of changes in wetland quality in the Wissahickon is that Chrysosplenium americanum, an indicator of pretty nice wetlands, was collected in the Wissahickon in the 19th century (by J. B Brinton on the 10th of June 1888 [with “fruit”, as indicated on the herbarium sheet], and by Albrecht Jahn on the 5th of May 1895 – both of these collections are at PH), but hasn’t been seen there recently.

And there are plants that we likely have fewer of now, most likely due to increased forestation (succession, that is) and development – like Hypericum gentianoides, which does occur in Philadelphia today (it was flowering in Haddington Woods, out by Cobbs, on the 2nd of September 2015), but we don’t see it often.  Barton (1818), however, notes it as: “In exposed situations on sterile soil; generally on roadsides; not uncommon.”, and it is included in Keller and Brown (1905), and Rhoads and Block note it as being “common” (though this is not a particular note about Philadelphia).  Also, in the Plants of PA database, there are multiple entries, indicating that it was collected multiple times in Philadelphia (from: Byberry, Cedarbrook, Germantown, Holmesburg, Mount Airy, Olney, Shawmont, Wissahickon Creek, Cedarbrook, Germantown), and in the herbarium of the Academy of Natural Sciences, there are multiple collections, one of which has on the label:

“Remains of last year’s plants forming almost pure stands in open
Coastal Plain sand-gravel; growing out of a covering of Cladonia.
This area was formerly covered by timber but is doomed to destruction
by real estate development.  S. W. corner of Cheltenham Avenue and
Easton Road.
J. W. Adams  48-33
April 6, 1949”

There are 6 more collections at the Academy, whose labels read: 1) “1 Aug 1849  Germantown” by “R. C. Alexander”; 2) “Dry Sandy Soil / Olney, Phila Co. / July 30, 1922 / Collected by R. R. D.” [= R. R. Dreisbach] coll# 1-155; 3) “above Shawmont, e. side / Schuylkill. Phila Co Pa / Collected by S. S. Van Pelt / Aug 5 1902”; And another: 4) Wissahickon, coll: S. S. Van Pelt – Aug 15 1902; 5) “Openings between coarse grass tufts on sandy slope 3/4 mile south-southeast of Byberry / Edgar T. Wherry / September 19, 1954”; 6) “Weedy roadsides and old fields / 1 mi. n.e. of Mt. Airy / Florence Kirk / August 3, 1949”

And so we see that this plant of open places was historically pretty common, though it does not appear to be quite as common as it once was, here in Philadelphia.

There is, I should say, also continuity through time here – hemlocks have been here and are here now.  And many other plants, animals and fungi have been documented to have been here in the past and remain here to this day.  These include plants that are parasitic upon other plants – these persist as well, 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.”  (however, in Norman Taylor’s 1915 Flora of the Vicinity of New York, which includes Philadelphia, he lists Conopholis americana for PA as “Bucks, Delaware, and Chester Counties” (that is, not Philadelphia); he also calls it “A rare and local plant” and its habitat as “In rich woods, usually at the bases of oak trees… Rare”; in Rhoads and Block (2007), the Plants of Pennsylvania, they note of squawroot: “parasitic on Quercus spp.; occasional in forests, mostly S and W”). [one wonders if this plant’s populations have grown more abundant in the past hundred years due to expansion of oak populations which grew due to decrease in population of their main competitor, the American chestnut, which decreased due to the introduction of the fungus Cryphonectria parasitica, the causative agent of the chestnut blight, doesn’t one?]

And there are plants that we still have, but in very different places, as we can read from Bayard Long’s 1922 paper in Rhodora (vol. 24), “Muscari comosum a new introduction found in Philadelphia” [the common name for this plant is grape hyacinth]:

“The collector of the specimen of Muscari comosum, Miss Adelaide Allen, fortunately was able to designate exactly where it had been obtained, as the spot lay along the familiar route from her home to school. Through her kindness, and the interest of Dr. Keller, we learned that it grew along the sides of a dyke, running in to South Broad Street from outlying farm houses, near League Island Park, in the southern portion of Philadelphia. This area consists in large measure of the extensive alluvial flats and marshes of the lower Delaware, more or less intersected by ditches. The region is not yet built up to any extent and the more elevated portions are frequently occupied by truck-farms. The southern extension of Broad Street, with its trolleys, offers one of the chief lines of travel in this particular locality, and the nearby farms often obtain access thereto by dykes laid down over the low meadows and more impassable places. These dykes are continually augmented by the dumping of ashes and rubbish down their sides. [note that the Dr. Keller mentioned above is the same Keller of ‘Keller and Brown’, mentioned previously]

In such a habitat from a detailed sketch map furnished by Miss Allen the Muscari was found growing.”

This plant persists from then, as is noted by John M. Fogg, Jr in his “Annotated checklist of plants of the Wissahickon Valley”, published in Bartonia (vol. 59) in 1996: “Muscari botryoides. Grape-hyacinth.  Introduced and naturalized from Europe.  Occasional in woods and clearings.  Thomas Mill Road.” (and it still persists to this day – on 14th of April 2014, it was flowering quite well along the Wissahickon, for example in the floodplain just downstream from the Walnut Lane Bridge; it was flowering here the week of the 13th of April 2015) [note also that League Island Park was relatively recent, in the 1920s, having been acquired by the city in the 1890s by purchase/taking of a variety of tracts (total initial cost: $399,670), as provided by an ‘Ordinance of March 11, 1895, “appropriating League Island Park as an open public place for the health and enjoyment of the people.” ‘ (Appendix to the Journal of the Common Council, 1897-1898)]

And there are animals that also span the temporal divide – consider the Virginia opossum which, as is noted in Whitaker and Hamilton’s Mammals of the Eastern United States (3d edition; 1998), can live many places: “The opposum’s adaptability to a great variety of habitats, ranging from forest to purely agricultural lands, explains its success in the eastern United States.  It is often quite common even in urban or suburban areas, and many are found dead on the highways.” and “The opossum is a solitary wanderer, remaining in no one place for long, and may be found far from trees.  Its daytime den is in a fallen log, a hollow tree, a cleft in a cliff, a brushpile, a tree nest of a bird or squirrel, a woodchuck or sun burrow, or a recess under a building, or in many of other protected situations.  Opossums do not dig their own dens, and thus are dependent on other animals, primarily the woodchuck and skunk, for ground burrows.” – they mostly den in wooded areas, arboreally as well as on the ground (and “in snags and leaf nests probably used or constructed in years past by squirrels”), though they have also been reported to den in an old field.

This marsupial adaptability is reflected in the current presence of numerous opossums (opossa?) in Philadelphia today and their presence a century ago, as we see evidenced in the number of individuals presented to the Philadelphia Zoo for accession to its menagerie, in the early part of the 20th century, that came from Philadelphians – for example, from the “List of Additions to the Menagerie during the Year Ending February 28th, 1914”: “1 opossum presented by G.W. Cassel, Philadelphia.” (13 November) and “1 opossum ([male]) presented by Mrs. George Biddle, Philadelphia.” (9 December) and “1 common opossum ([male]) presented by Harry Rathbone, Philadelphia.” (13 January) and “1 common opossum ([male]) presented by Miss Theresa Hayes, Philadelphia.” (22 February); or for the year ending February 28th, 1914: “1 common opossum ([female]) presented by Walter Ellis, Philadelphia.” (13 March) and “1 common opossum ([female]) presented by Mrs. Harrold E. Gillingham, Philadelphia.” and “1 common opossum ([male])  … presented by Frank G. Speck Philadelphia.” (22 November) and “1 opossum ([female]) presented by Mrs. A. H. Gerhard, Philadelphia.” (1 December) and “1 opossum ([male]) presented by William F. Girhold, Jr., Philadelphia.”; and for year ending February 29th, 1912: “1 opossum presented by Master Ralph Fritts, Philadelphia.” (13 May) and “1 opossum presented by Guy King, Philadelphia.” (28 December) and “1 opossum presented by Mrs E. A. Cassavant, Philadelphia.” (4 February) and “1 opossum presented by The Walter Sanitarium, Walter’s Park, Philadelphia.” 18 February) and for year ending February 29th, 1920: “1 common opossum presented by Thomas Oakes, Overbrook, Pa.” (12 April)  and “1 common opossum a presented by Dr. Frank Fisher, Philadelphia.” (3 October) and “1 common opossum ([female]) presented by John A. Caraher, Philadelphi” [sic] (30 November) and “1 common opossum (male) presented by John J. Daly, Philadelphia.” (23 February).  All these and more can be read in the Annual Report of the Board of Directors of the Zoological Society of Philadelphia volumes 40-49; be sure to note also how many people from Philadelphia were donating alligators in those years.  Note also the numerous birds and other animals that were either “caught in the garden” or “found in the garden” (including at least two screech owls).

While the above mentioned animals were caught and presented live to the zoo, I do want to note that opossum were hunted and eaten here historically, as well, as we can see from an 18th century letter from Father Joseph Mosley, to his sister (writing from St. Mary County, Maryland – 1st of September 1759; the following letter was published in the Records of the American Catholic Historical Society of Philadelphia, Volume 17; 1906)

“Our game is very plentiful, as in shooting possums, deers, wild turkeys, raccoons, squirrels, pheasants, woodcocks, snipes of different sort, teal, wild ducks, wild geese, partridges, &c., but all different from birds of the same name in England, and all very good eating except the raccoons. Panthers have been seen in this country, but not of late years. We have turtles, or tortoises, of all sorts We abound with all sorts of fruits, so as even to feed the hogs with peaches that would sell very dear at your market.”

You’ll notice that deer are on that list, and second only to possums – these animals are quite common now in Philadelphia, but this was not always the case, as is evidenced by the purchase of a male white tailed deer by the Philadelphia Zoo, on the 4th of April 1911, as is noted in the Annual Report of the Board of Directors of the Zoological Society of Philadelphia volumes 40-49; “List of Additions to the Menagerie during the Year Ending February 29th, 1912” … “1 white tailed deer ([male]) purchased.”)

I’ll note here that peaches, mentioned in Father Mosley’s letter, though an introduction from the old world, have been here for quite some time – Peter Kalm mentions them multiple times in his Travels into North America; they are mentioned by Peter Collinson in letters he wrote to John Bartram; and William Penn mentions them in one of his letters home: “Here are also peaches, and very good, and in great quantities, not an Indian plantation without them; but whether naturally here at first I know not.“ (extract 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,”).

But back to the opossum –  while this animal was present here, it was not quite as common towards the mid-part of the 20th century as it is now, as is noted in Philadelphia: a guide to the nation’s birthplace (1937; Pennsylvania Historic Commission and Federal Writer’s Project):

“With so much of the wildwood atmosphere still preserved, Philadelphia has its share of bats, squirrels, chipmunks, rabbits, weasels, and the smaller rodents, such as the meadow mouse and the white footed deer mouse.  The raccoon and opossum are now rarely found, but are still encountered in the deeper rural sections of this district.”

And so, in the overall change of Philadelphia’s ecosystem over the centuries, many of the moving parts have remained, though they may have shifted gears a bit.

This succession, the change in urban ecosystems through time, is not, as is illustrated by the Hermit Lane pines, strictly a passive process.  It is, or at least can be, actively facilitated by people and their (or “our”, I should say, since we are all people) management – by planting those white pines, for erosion control or for reforestation, this altered the pattern of succession that we would have seen otherwise, from what we most likely would have seen, or at least what I’d expect to see, which would be a stand of tulip poplars, that would’ve now had trunks about a meter across and would now be just about reaching the end of their lifespan, to this massive stand of white pines that we see today.  This occurred not by chance, but by human intervention, and is the reason that what we see today is there as it is.

By looking at these old photos and maps, by reading old reports and census documents, by understanding landscape ecology and succession, we can see how what was done before has brought about what is here today – we can see the enormous changes that have affected our city, and often be quite surprised at just what those changes were and how they came about.

It can be surprising to realize that Philadelphia has more dense forest today than it did a hundred years ago, and also then to learn the other impacts this brings about, on birds, as mentioned above, and also on water quality, among other environmental factors. And it is key to realize that this did not happen by chance; ecology in cities is due directly to actions by people, and always has been, for a very long time, as we see from those pines that were planted a century ago.  We are part of these ecosystems, and thoughtful decisionmaking, such as that in the Philadelphia Parks and Recreation’s recently released Parkland Forest Management Framework, is needed for making these decisions in a way that will be amenable to all of us in and for Philadelphia, both now and in the years, decades, and centuries to come.

Ailanthus, House Sparrows, and Eastern Gray Squirrels

Matt Kasson (currently at Virginia Tech) has tracked the movement and growth patterns of Ailanthus altissima, the “tree of heaven” –

A brief historic note on the Ailanthus, from the “Conchologists’ Exchange“, where John Ford (Philadelphia, PA) writes of the genus of land snails, the genus Helix, in 1887:

“Unfortunately there are not many to be seen at the present time as the blasting for the new River Road destroyed most of the Ailanthus bushes upon which they chiefly fed. Only a short time before the rocks were removed I took over 200 specimens from a space less than 50 feet square. A number of these were captured upon the Ailanthus bushes in the act of eating the foul smelling leaves, a fact which seems to prove that no plant is too offensive to be used as food by some animal.  Very many of these specimens were in perfect condition; as may be learned from the sample in the Philadelphia collection on the second floor of the Academy of Natural Sciences. The writer was the probable discoverer of this colony, which it is safe to say has never been equalled in this region either in number or in perfection of form and color.

Nearly opposite to this locality on the west side of the Schuylkill just south of the bridge crossing the old carriage road very many H. libera and H. allemata may be found Here the conditions are much the same as were those already described; large stones being scattered about and many Ailanthus bushes growing between.”

Another organism that eats Ailanthus altissima is the Ailanthus silkmoth, as is detailed in Ken Frank’s History of the ailanthus silk moth (Lepidoptera: Saturniidae) in Philadelphia: a case study in urban ecology, from volume 97 of the Entomological News (1986), available for perusal here.

And the Ailanthus webworm can currently be found in Philadelphia:

And as we read in the  Proceedings of the Academy of Natural Sciences of Philadelphia, Volume 34 (1882):

“Prof. Leidy further remarked that the past season had appeared to be favorable to many of the Lepidoptera. Our shade-trees had been greatly ravaged by the Orgyia; many of the poplars had suffered from the Clostera inclusa, and he had observed an unusual quantity of the Ailanthus silk worm, Attacus cynthia, upon the Ailanthus-trees. The latter was introduced here in 1861, by Dr. Thomas Stewardson”

Additionally, from Scharf and Westcott’s History of Philadelphia (1884):

“The State-House [= Independence Hall] pavement was a wide and unpleasant place in warm weather when the sun was shining. Fully exposed, and reflecting back the heat, it was, in consequence of the buildings being far back from the line of the street, less attractive than sidewalks across which neighboring houses threw a shade in some periods of the day. No attempt was made to introduce any improvement until the fall of 1821, when trees were planted in front of the State-House, extending from Fifth to Sixth Street. Poulson [=publisher of the Daily Advertiser] said in reference to this improvement, “It will be a salubrious exchange for the arid bricks that have been broiling our brains there for fifty years.” The trees chosen were ailanthus, noted for quick growth and thick foliage. In ten or fifteen years the front of the State-House in summer time was as umbrageous as a forest. Afterward these trees were attacked by worms, and were ordered to be cut down. The axe was applied at some little distance above their roots, and in a few hours the grove, once the glory of the city, the favorite place in which the town politicians assembled to talk about nominating and elections to discuss political affairs -where they were commonly called “tree toads” – presented the dismal appearance of a forest in which the wood-choppers had been entirely too busy. The public could not stand that. In a short time new trees (silver maples) replaced the ailanthus, the idea being from experience that they would not be disturbed by the worms. They grew finely, and in a few years the grove in front of the State-House was restored to its original beauty. But just about that time the worms gave proof that they would change their diet upon necessity rather than starve. The ailanthus and paper mulberry having been almost exterminated as a sidewalk tree in the streets of the city, the worms accommodated themselves to circumstances, and condescended to devour the leaves of the maples.

In time the English sparrow was imported, and he justified the expectations founded upon his change of country by attacking the worm vigorously. In the meanwhile many years had gone by, and a considerable number of the trees had yielded to natural decay. When about 1876 it was determined to replace the brick footways by a pavement of slate, there were very few of the old trees left. It was not difficult to dispose of them. By covering the surface with the stone and making no provision for watering the roots, the remaining trees gradually died off, so that in 1884 there is probably no survivor of this most beautiful grove which for many years was the most attractive place on Chestnut Street”

Note: Philadelphia was the site of what was most likely the largest introduction of house sparrows (Passer domesticus) into North America: one thousand of them, in 1869

Philadelphia also appears to be the first city in North America in which “free-living” squirrels were released for the edification and enjoyment of the populace, and they (the squirrels, that is) were even provisioned with food and little homes, beginning in 1847, in Franklin Square – this was to be followed by multiple later introductions in Philadelphia, all of which rapidly led to squirrels being found (by 1853) in Independence and Logan Squares as well as other locales in the city; in 1864, however, a report was issued at the city’s request (due to worries that the squirrels were eating birds and their eggs, and also thereby increasing insect populations) by PHS‘s “Committee on Entomology” evincing concern that these little rodents were negatively impacting bird populations due to competition for e.g, nesting sites in trees, even though they (the squirrels, that is) did not appear to be eating the birds nor their eggs, and shortly thereafter eradication and removal efforts were implemented, and these appear to have entirely removed squirrels from the city, thereby clearing the way for the abovementioned English sparrows  – this is discussed in the recently released paper “The Urbanization of the Eastern Gray Squirrel in the United States“, in the Journal of American History; I note that squirrels had returned to Philadelphia by the early 20th century, as we might infer from reports of them being given to the zoo by Philadelphians: “List of Additions to the Menagerie during the Year Ending February 28th, 1914″ … “1 gray squirrel presented by W. Stokes Kirk, Philadelphia” (12 July); “List of Additions to the Menagerie during the Year Ending February 29th, 1912″ … “1 gray squirrel presented by G.H. Didinger, Philadelphia” (6 May); “List of Additions to the Menagerie during the Year Ending February 28th, 1917″ … “1 gray squirrel presented by George Swisher, Philadelphia” (12 August); but there weren’t many of them given, as compared to opossums, for example; the aforementioned records can be read in the Annual Report of the Board of Directors of the Zoological Society of Philadelphia volumes 40-49)

The changing mood about the the English Sparrow is captured in the following article from The Great Round World (“a news magazine for busy men and women”), volume XXI, for the week ending June 6, 1903:

Reversed Fame

To have one’s beneficent work appreciated and praised and then have it suddenly depreciated and denounced is the lot which fell to Mr. John Bardsley, of Germantown, Pa., some years ago.  The Philadelphia Record tells the story:

“There is a little old house in Germantown, at the northwest corner of Main and Upsal Streets, that is in a certain sense historical. In this house some thiry-five years ago, lived ‘Sparrow Jack,’ and the building, therefore, has the name of “Sparrow Jack’s house.’ Jack was an Englishman, John Bardsley, and through the influence of William F. Smith, a Germantown Councilman he was sent to England to bring over a lot of English sparrows, the idea being that the sparrows would destroy the caterpillars that infested the trees. The few sparrows Bardsley imported are the ancestors of the millions that now thrive in Philadelphia. The importer was highly praised for his work during the first year or two, and his nickname of ‘Sparrow Jack’ was a title of honor in which he took great pride. Later on, however, as the sparrows began to become a nuisance, the nickname came to have a reproachful significance and in the end it became a term of opprobrium.”

Sparrow Jack is buried in Ivy Hill Cemetery:

The Ailanthus was a popular tree in the early 19th century, but fell into disfavor, as is covered in the Annual Report of the Secretary of the Board of Agriculture, Volume 32 (Massachusetts; 1884):

“From its rapid growth and tropical appearance it soon became a favorite, and was planted extensively in the cities of New York, Philadelphia, Providence and Newport, and the demand for the young trees far exceeded the supply. As soon as the trees were old enough to produce flowers, it was discovered that they emitted a very offensive odor, and the pollen which fell on the roofs of neighboring houses rendered the water falling on those roofs unfit for drinking or culinary purposes. On discovering these objectionable features in its character, those who had cherished this rare exotic were suddenly seized with a feeling of disgust, and war was declared against the offending ailanthus, resulting in almost its complete extermination. A few may be found scattered over Rhode Island, and in some of the villages of New England, lineal descendants of a despised and persecuted generation.”

However, it was still recommended for planting for forestry well afterwards, as is indicated in the Reports of the State Board of Agriculture (PA) for 1894:

‘The following questions from the query box were read and briefly discussed:

“What forest trees are most profitable to grow, and should they have a place on the farm?”

Mr. Brinton. That depends upon circumstances. If for fire wood, I would say Ailanthus. If for general purposes, black walnut, or where for fence posts, yellow locust.’

But in cities, it was generally not well regarded – an example of this we see in Christopher Morley’s Philadelphia (published in 1990, edited by Ken Kalfus; the portion below originally published in 1920 in Morley’s Travels in Philadelphia), in the section titled ‘the Indian Pole’, where he writes of the neighborhood around Callowhill east of Broad:

“Down their narrow side alleys one may catch a glimpse of greenery (generally the ailanthus, that slummish tree that haunts city back yards and seems to have such an affinity for red brick).”

To read even more about the Ailanthus, see here:

The Invasive Ailanthus altissima in Pennsylvania: A Case Study Elucidating Species Introduction, Migration, Invasion, and Growth Patterns in the Northeastern US, by  Matthew T. Kasson , Matthew D. Davis and Donald D. Davis; Northeastern Naturalist, 20(10):1-60. 2013.
Or here:
And, in recent news, the Spotted Lanternfly (Lycorma delicatula) has recently (fall 2014) been discovered in the US, in Pennsylvania:
Adults of this species feed on Ailanthus in the autumn, and it is preferred by them for egg-laying as well.

The Spruce Street Swamps

If you were to walk down Spruce Street in West Philadelphia today, going westward from the University of Pennsylvania, you would see a lot of houses, and a lot of pavement – concrete sidewalk, asphalt streets, building materials of numerous variety, all covering the ground that lies beneath.  There are, of course, also many trees you would walk by – the magnificent Franklinia at the southeast corner of 42d and Spruce is a classic, and directly across from it, at the southwest corner of that same set of cross streets, is a large and majestic, though wildly trimmed, Paulownia.  Also along that south side of the street is a row of houses dating from the 1880s, and they are guarded out front by their regularly spaced and by now quite large squadron of Japanese maples.

And the north side of the street is not lacking for lignin either – there is an enormous white oak in the churchyard there, on the north side of the street, in the same block that includes the Sadie Alexander School, between 42d and 43d Streets, north of Spruce.  In that yard are also two pines – one an eastern white pine (Pinus strobus) and the other a Himalayan pine (Pinus wallichiana) – paired up against each other, along 42d Street, ready to be compared.  These are two tree species that I’d found difficult to differentiate until I came across these two examples right next to each other, set up like a coniferous teaching collection, just waiting for some comparative taxonomy.  Both of these species are five needle pines (pine trees’ needles, of all pine species, are arranged in clusters, called fascicles, and all pines either have five needles, or two-or-three needles), and those needles are somewhat light in both strobus and wallichiana, and both of them have rough, platey bark, and so it’s not easy to tell them apart, until you see them right next to each other, as one does here at 42d and Spruce.  Here you can see that the needles of the Himalayan pine are longer, and more droopy (“pendulant”, one might say), as compared to the white pine’s needles, which are more upright, and look, to me, a bit like little fireworks’ bursts, as compared to the more hanging tresses of the Himalayan pine.  (also, as my friend and botanical compadre Doug Goldman has reminded me, wallichiana cones are much larger than those of strobus)  And if you go and take a look at them, and look at their bark, you’ll see by the horizontal arrangement of holes on the wallichiana, and the absence of such holes in the strobus, that sapsuckers (a kind of woodpecker) are able to tell these two species apart.  Both of them are quite attractive trees, and both do quite well in Philadelphia, and I hadn’t realized how common the Himalayan pine is here until I learned to tell it apart from its cousin, and these two trees at 42d and Spruce were quite helpful for getting me to learn how to do that.  (to read more about this block, see here: )

And so, I guess I’ve made the point quite well that there are quite a few trees along Spruce Street here – now, on with the peripateticism…

As we are walking along, heading west, if we were to look back towards Penn (fondly, one hopes), we’ll see the street sloping down, and we’ll realize that our legs might be a little sore from having been walking uphill to get where we are, and that we most likely broke a sweat (we’d definitely be sweating on a day with weather like we’ve been having recently), and then as we turn around, facing our goal of heading west, then we see that there’s still a bit of hill ahead of us – up to 45th Street, where there is a rise that we can stand on top of like a little king of the world, and then, towards 46th Street, after we cross the rise, the ground angles downwards.

If we were here a hundred and twenty years ago, this would have looked quite different, though some of the angles would have still been similar.  In the early 1890s, the surfaces we see now would not have been here, not the sidewalks, nor the asphalt.  Though this dip was here, it was through a very different landscape – it was a different world back then, and one we know about in surprising detail, due to the wanderings of Alexander MacElwee, among other sources.

The go-to book to learn about botanists of Philadelphia up until the 20th century is John Harshberger’s The Botanists of Philadelphia and Their Work, and the following biographical information is from that book –

Alexander MacElwee was born in Scotland in 1869 to a relatively large family (he was one of eleven children).  Alexander was the eldest of the younger MacElwees, and he went to school before finally getting to go to work at the age of twelve years old.  After a couple of years of working in Glasgow, he went to join his parents who had already arrived here in the new world of Philadelphia.  His first job, this was in 1883, was working in a garden at 39th and Walnut – the garden was owned by A. J. Drexel (see the 1895 map here:, who would go on to start up the Drexel Institute of Art, Science, and Industry, which would then go on to become Drexel University in west Philadelphia, just north of Penn. (NB: that location is now occupied by Penn’s Fels Institute of Government – do any of the plants now there date to MacElwee’s time?  I don’t know)

MacElwee worked in Drexel’s garden, and also began to learn formal botany by going to meetings of the Botanical Section of the Academy of Natural Sciences, and after a few years, he moved up, both geographically and hierarchically – he went to work at Hugh Graham’s nursery, right near Girard College in North Philadelphia .  This nursery was at 18th and Thompson, and Mr. MacElwee “had charge of several houses, one entirely of ferns, another of palms, etc (Harshberger, 1899).  [The Graham Nurseries was at the NW corner, caddy corner across from St. Joe’s, as may be seen on G. M. Hopkin’s 1875 map of Philadelphia – incidentally, as is noted in his obituary in volume 38 of the magazine “Christian Nation”, Hugh Graham worked as department manager for John Wanamaker prior to becoming a somewhat major Philadelphia florist (he also had “large nurseries at Logan Station, near Philadelphia” [as of 1895, they were at 13th and Loudon, bounded on the west side by Old York Rd]); Mr. Graham died of pneumonia on the 14th of March 1903.]

But MacElwee was to move on soon again – to work as an apprentice bricklayer for a time (during which he had the spare time to expand his knowledge of natural history by field work and by working with botanical museum collections), and then on to work in John Wanamaker’s garden in Jenkintown, and then on to the College of Pharmacy (now the University of the Sciences in Philadelphia) to work with their museum collections of dried, pressed plants.  And as he worked, he learned, and in 1894 he went to work for the University of Pennsylvania laying out the Botanical Garden that was being planned.

As we learn from MacElwee’s obituary in Bartonia (the journal of the Philadelphia Botanical Club), No. 9, 1925-26, “Mac” continued to work at a number of places, until 1917 when he “was appointed landscape gardener by the park commissioners of Philadelphia.”  His dream was to have an arboretum, and he worked assiduously towards that end – traveling to the Arnold Arboretum, to the Brooklyn Botanical Garden, to the Seed and Plant Introduction Service in Washington, DC.  He gathered an immense number of plants and brought them back home to propagate – “thousands of the rarer rhododendrons, flowering cherries, barberries, hydrangeas, hollies, lilacs, roses, crab apples, oaks, loniceras, etc., etc., were started in the Park nurseries, intended for the Arboretum.  Now that the master spirit has gone the project of the Arboretum has rested almost inactive, but these young trees and shrubs remain and form a nucleus from which MacElwee’s dream should be developed.”  Mr. MacElwee passed away on the 23d of January 1923.

While he was alive, Alexander MacElwee, like most botanists, liked to be on the go – he was like this with respect to his working life, as we have seen in the above paragraphs, and also with respect to his day to day ways and wanderings, which he diligently recorded with pencil, pen and paper.  And from these writings of his perambulations, we can learn what was here before.

MacElwee’s field notes are in the archives of the Academy of Natural Sciences, and going through them, with the help of the Academy’s archivists, Clare Flemming and Megan Gibes, we see a man who liked to walk, and they also show with great detail the places where he walked.

Like 46th and Spruce, for example, the dip in the road that I mentioned above.  MacElwee walked near there, in the early 1890s, and after he got home, he wrote the following:

“March 27, 1893
This eve, when coming home from work through the marshy hollow south of Walnut St. and west of 46th Street, I found some boys fishing for tadpoles.  I was not aware that one could find tadpoles this early in the season.  These I seen were of good size, having heads about 1/2 long, and tail twice as long.  The boys caught them by dipping up a large can of water out of the stream and then pouring the water out slowly and catching the tadpoles as they appeared and putting them into another which contained their captives.  One of the boys said he was going to raise them in an aquarium.”

(the underlining is from the original)

This isn’t the only mention he makes of this area – in an entry for the 1st April  1893, he mentions finding Alnus (alder), in flower, in a marsh west of 45thSt. and between Walnut and Spruce.  A few days later, on the 6th of April 1893, he came across “A large spreading tree in the hollow 46 + Chestnut”, at the southwest corner, that was “Probably Acer saccharinum” (i.e., silver maple – a tree still commonly seen throughout west Philadelphia as a street, yard, and park tree – but on its own, without humans planting it, it’s generally a wetland tree).

A bit later on in the year, on the 17th of June of 1893, Alexander MacElwee took a walk and came across a shrub of the Eastern Wahoo (Euonymus atropurpureus) “in front of farm house about 47 and Pine St.”, and some American elderberry (Sambucus canadensis) in the “Spruce St. Swamp”,. as he called it.  That same day (the 17th of June, that is), and right nearby, he saw an American hornbean (Carpinus carolinianus) “At spring W. side of Spruce St. swamp”.

If we look at Ida Keller and Stewardson Brown’s Handbook of the Flora of Philadelphia (published in 1905), we see a couple of entries that also let us know that this area was a wet one, such as –

“Sagittaria Engelmannia …Shallow water.  Summer.
Philadelphia – 46th and Spruce Streets”

This entry is quite likely based on a collection that is in the herbarium of the Department of Botany of the Academy of Natural Sciences, here in Philadelphia – it is a specimen labeled Sagittaria latifolia (the current name of this plant that Keller and Brown list under S. engelmanniana), and the label’s locality data says “stream near 46th and Spruce Sts” and is dated the 4th of September 1887.  [this also indicates are reasonably high quality wetland was there at the time – in Small et al’s 1994 paper in Restoration Ecology, “A Macrophyte-Based Rapid Biosurvey of Stream Water Quality: Restoration at the Watershed Scale”, they report Sagitaria latifolia from nearly 27% of the high quality streams they surveyed in the Chesapeake Bay watershed, yet not at all from their low quality stream sites]

Another entry in Keller and Brown’s flora locates a wet area here – a record of Salix alba (white willow), which prefers “Moist soil” (as Keller and Brown note) is also there, noted as being at 46th and Chestnut.

However, this area wasn’t all swamp and wetland – there would have been some drier, upland areas, too, as is indicated by another collection by Alexander McElwee, of Castanea dentata, from 46th and Spruce, this one from the 3d of July 1887 (and also currently accessioned in the Academy’s herbarium).  Castanea dentata, or the American chestnut, as it is more commonly known, isn’t one to grow in swamps around here (though up in New England I would see it sometimes in moist areas), and so its presence, as indicated by this collection, in turn indicates that some areas were up above the wet – it wasn’t all swamp and marshes.

And so from these notes from these fieldbooks in the Academy’s archives, and from collections in the Academy’s botany department, and from Ida Keller and Stewardson Brown’s book, we see that up until the end of the 19th century this was an open area, the area nearby to 46th and Spruce, with farmhouses, and wetlands – streams, hollows, and marshes.  And it went on, this open area, out south and westward:

“On one of the vacant fields near 50 + Baltimore Ave. is a large spot where sods had been cut off last spring.  I notice that all this spot (and it is quite extensive) a thick crop of Ambrosia artemisaefolia (roman wormwood) has sprung.  It is rather remarkable.  This land has not I suppose been turned under by the plough for years.  There are one or two other things among it, but the Ambrosia predominates where the sod has been cut off. growing densely to a uniform height of 7 or 8 inches.  In many cultivated fields further on  I noticed plenty of it.  But it is not so remarkable in such situations.”

And as further evidence of open areas in this part of town, in Keller and Brown’s 1905 Flora of Philadelphia and Vicinity, they list Centaurea nigra (knapweed) as having a habitat of “Waste places” and a locality of “48th and Baltimore”.

There were also more wet areas, going west – Black Oak Park (now called Malcolm X Park) had some, out at 51st and Pine (the park extends down to 52d and Larchwood), as is shown by the entries in the Plants of Pennsylvania database for Carex annectens and Cyperus odaratus, with locality data identified as “Black Oak Park” – both of these are facultative wetland plants (that is, they can grow in wet areas, but don’t require it, and can grow in drier spots), and so while they don’t indicate absolutely a wetland, they do imply some moist area was there, in what is now a dry city park, still with trees throughout its environs, though, and even at least one that is a wetland tree.  At the northern boundary of the park, between 51st and 52d Streets along Pine Street, there is a magnificent blackgum tree (Nyssa sylvatica), a tree also known as the tupelo –  a tree that on its own is a wetland plant, but also does pretty well as a tree in drier areas (like a city street or park), and it stands tall in the middle of west Philadelphia, at the northern border of Malcolm X Park.

By the 1920s, at least, this park was pretty dry, as is indicated by the following photos:

Black Oak Park (now called Malcolm X Park) – entrance – 51st and Larchwood; 16th of May, 1927 – image from

Black Oak Park (now called Malcolm X Park) – 52nd and Pine Streets – 28th of March 1921 – image from

These scattered collections and references illustrate just how much of west Philadelphia had wetlands and hills, and wetland plants and upland plants, and farms and farmhouses, too – up until at least 1910, this area west of 46th Street was still open, as is indicated by G. W. Bromley’s map (accessible here: ).  And if one were to look at Mr. Bromley’s 1895 map, a map that is also available at the aforementioned address, one would see a stream running up north along 46th Street, and by looking back a little further in time, for example to Samuel Smedley’s 1862 map, one would see that this stream was a tributary of Mill Creek, which flowed into the Schuylkill after stopping for a break at a mill pond at what is now Clark Park (a large park that spreads south from 42d and Baltimore Avenue). [and there was “Desintegrated Feldspar.  Kaolin.” here as well: “Feldspar in a state of decomposition exists on the canal road, and on Mill creek, near the Baltimore turnpike…” (Isaac Lea, “An Account of the Minerals at present known to exist in the vicinity of Philadelphia”, Vol. 1, Journal of the Academy of Natural Sciences of Philadelphia, December of 1818)]

These areas, while now paved over, filled in, and leveled, still have parks and yards and street trees – they have changed and been changed, been paved over and built upon, but as always, life remains and plants grow, in different environments than before, and often, though not always, with different plants than were there before, but marking, in everlasting flux, the perpetually changing times the city lives through, always and in all ways, and endlessly transformed.

And of course it is not only the plants and the landscape that change, but the animals as well, such as the birds, as is noted in George Nitzsche’s 1917 article in the Penn Gazette (“Bring Song Birds Back to Campus!”), where he notes a list of 72 birds compiled in 1906 by Cornelius Weygandt (Professor of English at Penn) and his compatriots, and comments on the changes in the avifauna, from the ten years prior, to his time then – he notes one change especially: “The English sparrow has invaded, in greater numbers each year, our suburbs, our public parks and squares, and other little breathing places in great cities.”  This was due in part to expanding urbanization but also to the introduction of this European species to the new world, an introduction that was the largest here in Philadelphia: “This year (1869) witnessed the importation, in one lot, of a thousand Sparrows by the city government of Philadelphia ; and this probably Is the largest single importation of Sparrows ever made to this country.”  (Walter Barrows, 1889, “The English Sparrow in North America Especially Its Relations to Agriculture”)  And so the changes wrought come from many causes.

Of course, while some things do change, others don’t so much, and so I would like to close with a final quote from Alexander MacElwee, from 1893:

“Requisites for the Botanist and Entomologist while on the march.

1:- Money. This is an indispensable article and mainly used for carfare, ferries, etc

2:- Provisions. This may consist of a good lunch of sandwich.  pastry or extra side dishes can be dispensed with.  It is surprising how delicious a couple of slices of bread and butter with a little cheese is after tramping several miles in the country, washed down with a draught of water from a spring of wayside creek.”

Plus ça change…

To read more about West Philadelphia’s ecological history, see here:

Cedar Grove

There used to be a train station, in the lower northeast of Philadelphia, called Cedar Grove.  It was on Tabor Ave, just a bit southwest of Godfrey Ave, and was on the Frankford spur of the train line that goes to Fox Chase, which is in a bit farther part of the northeast of Philadelphia.  This spur went just about all the way to Frankford Ave, ending at a terminus between Unity and Sellers Streets.  It was a train line that carried freight and also passengers – starting in the late 19th century, it lasted well into the 20th century, going behind the Sears on the Boulevard, along the eastern edge of Northwood Park, and among the houses of heavily populated Frankford.

It also traveled through Cedar Grove.  This was the name of the neighborhood, as well as the train station, and up through the early part of the 20th century, it had open marshes and thickets, and forests with spring wildflowers, and wild flocks of birds filling the sky.

Cedar Grove is just to the east of Tacony Creek and just above the Boulevard, and in the early part of the 20th century it was quite unbuilt.  There were woods there, with beeches and oaks, and poplars and sweetgum and ash trees and sassafras, too, all growing there among each other.  In the spring there were anemones and partridge berries on the forest floor – and hayscented fern was there, as was the trout lily, one of the beautiful wildflowers of the spring, which would’ve come up year after year alongside the mayflower that was there, neighboring side by side with the bellwort (Uvularia sessilifolia) and jack in the pulpits.

Another fern, royal fern, would’ve grown in low wet areas of the woods, and yet another fern, interrupted fern would’ve been a bit higher up.  Royal fern, whose latin name is Osmunda regalis, is in the same genus as the interrupted fern, Osmunda claytoniana.  The interrupted fern, however, likes it a little bit drier than its wetland cousin, and so would’ve been in areas a bit drier – upland and underneath the trees, growing along with and near the wood sedge that would’ve dotted the ground up there.

Dwarf ginseng was also in the woods of Cedar Grove, on the ground, growing among the willow oaks, and poison ivy scrambled there, too.  Pinxter, the azalea with its wild pink flowers, would’ve been a bright beacon in the forest of the early spring.

Beneath the beeches and the oaks were also Dutchman’s pipes, a plant also commonly called by its Latin name, Monotropa.  This is a parasitic plant, it doesn’t make its own sugar, it isn’t green, it doesn’t photosynthesize – it eats sugar that is carried through mycorrhizal fungi, this achlorophyllous plant parasitizing the fungus that in turn has gotten its sugar from a plant with which it is mutualistically symbiotic.

In addition to these forests, there were wide open flats, somewhat wet, in Cedar Grove, with sheep laurel and blueberries, and purple milkwort (Polygala sanguinea), too.  Swamp white oak and black willows made little canopies here and there in these wet areas, as woolgrass (Scirpus cyperinus) nodded in the breeze nearby, bobbing along with the rustling of the narrow leaved and the wide leaved cattails.  Swamp milkweed (Asclepias incarnata) attracted the butterflies, and close to the ground, trailing lightly and low, was the cranberry (Vaccinium macrocarpon).

And there were birds – enormous flocks of blackbirds flew above the flats.   And in the woods Eastern Towhees (which also used to be called, colloquially, “chewinks”) scratched and picked among the leaves, loudly and boldly, with White-throated Sparrows following behind them, picking through their trails.  American Kestrels (also known as sparrow hawks, back in the early 20th century) cruised above the long flat fields of Cedar Grove, and Ovenbirds walked among the forest trees, occasionally flying up to sit in a tree’s branch and sing.

Meadowlarks, now rarely seen in Frankford, used to be in Cedar Grove year round – in the middle of December, in flocks numbering to more than 25, they’d get flushed by a train going by and fly through the air.  And the Winter Wren was out along the train tracks, too, in the icy cold, a little chilled hobo out there in the sleet and snow.

So how do we know all this?  How can I say with such detail what was living and growing in Cedar Grove in the early 20th century, when I wasn’t there and wasn’t until many decades later?  Well, one can reconstruct former ecologies, one can estimate historic plant and animal communities, by knowing habitats of plants and animals, and figuring out, based on climate and soil and hydrology what the habitat of the site would have been in the past, and then, building from that information, one can construct a vision as to what would have been there in the past.  That’s one way to do it, and for most places in the world, that’s really the best you can do.

However, in Philadelphia, we very often have another way to do this – here, we have extensive written records and museum collections, and it’s amazing the level of detail available, documenting what has lived here before.  One might expect there to be records for cultivated plants in parks and gardens, because they were planted by people, and people can keep records.  But there is also extensive and intensive information available on many of the plants that grew without being planted by people, and for the animals that walked and flew among those plants.  Philadelphia’s rich history of natural history is unequalled for supplying this kind of information, and for keeping these records. [Note: There is also a record of a Herring Gull of which “Mr. Wm. Morris Whitaker also secured a specimen October, 1893, on a mill dam at Cedar Grove, Philadelphia, five miles from the Delaware.” from Witmer Stone’s “The Birds of Eastern Pennsylvania and New Jersey” (1894)]

And we can use those records, if we know about them, to learn about what was here before.  Or, if we don’t know about them, we can talk to those that do.  In 1910, Henry S. Borneman read a paper before the Historical Society of Frankford about the birds that were in the area, including Cedar Grove, in the late 19th and earliest 20th centuries.  Over a hundred years later, in 2012, Susan Couvreur and Diane Sadler, of the Historical Society of Frankford today, drew my attention to that work, with its richly detailed description of the bird life of Frankford, and also its discussions of the plants and habitats of the time.

There are also plants from Philadelphia that were, in many years past, collected, pressed, dried, and mounted on paper sheets, that are now deposited at the Department of Botany of the Academy of Natural Sciences of Philadelphia, and these plants that were collected decades ago provide evidence of what is no longer there.  There’s also a list of historic collections of plants from Philadelphia, that was extracted from the Plants of Pennsylvania database maintained by the Morris Arboretum, that was kindly provided to me by Ann Rhoads and Tim Block (botanists at the Arboretum).  This list provides an effective guide to the many collections from Cedar Grove that have been made in the past.

There were collectors in years gone by that allowed me to develop this wonderfully rich description of a site that has changed so much.  Walter Benner collecting sheep laurel (Kalmia angustifolia) on the 8th of July in 1926, in a moist thicket of Cedar Grove.  Samson McDowell, Jr collecting blueberry (Vaccinium corymbosum) in the moist woods there, on the 19th of May 1926.  These collections are now part of the Academy’s collections, and nearly 90 years later, their work allowed me to see first hand the plants that were there when they wandered through those open areas of Cedar Grove.

There are also maps, such as the 1895 and 1910 Bromley Atlases, from the Athenaeum of Philadelphia (available on, that show just how open the area was, how unbuilt it was a hundred years ago, and where the train line that cut through Cedar Grove went.

Taking these records, and applying some additional knowledge of ecology, we can describe Cedar Grove nearly as thoroughly as if we had walked through it ourselves – and a surprisingly detailed picture of this place in the early 20th century can be cobbled together.  Its open marshy areas and its forests, both of them rich with flowers and birds, the train line running through it, trees dotting the flats.  An evocative illustration can be drawn of a landscape that is no longer there.  And perhaps an evocative illustration can also be drawn of a landscape that is yet to be.