A Bear Visits Riverside Elementary

As reported in TapInto Princeton, a black bear stopped by Riverside Elementary School during school hours this past Wednesday, May 28. The school was in "lock down" mode for two hours until the bear had moved out of the neighborhood. (Photo by Syth Devoe) The school, whose mascot is the River Bear, was reportedly last visited by a real bear in August of 2022. 

This PrincetonNatureNotes website serves as a diary of sorts for bear visits to Princeton. A common cause of bear visits is young males seeking new territory. For previous posts, you can do a keyword search for "bear," but "latte" works pretty well, too. "Duck in for a latte" is part of a comic but accurate description I wrote in 2012 about how a Princetonian should behave when encountering a black bear. 

Some background info on black bears in NJ can be found in a MyBergen article. 

Update: Carolyn Jones' writeup in TapInto Princeton, "Hey, Princeton, Time To Be 'Bear Aware' -- American Black Bears Are Increasingly Common," gives a good overview, including an extensive interview with animal control officer, Jim Ferry. 

Maintenance Will Determine the Fate of the Betsey Stockton Garden

When I look at a plant, a garden, a meadow, a forest, I can see the future. It's a form of extrapolation, defined in the Oxford Dictionary as "the action of estimating or concluding something by assuming that existing trends will continue." I only realize now, writing this, that not everyone exercises such powers. Not everyone has been a gardener of landscapes for fifty some years, accumulating memories of myriad plant species and observing their behaviors. I've seen thriving raingardens and neglected ones, healthy meadows and forests, and degraded ones. I've observed how various invasive weeds spread and come to dominate, each in its own manner and at its own pace. These are the accumulated data points used to predict the future.

One very satisfying thing about extrapolation is that I can see, in my mind, the flower a bud will become. But with that same power to see a garden blooming while still in bud, I can look at a garden in what for others is glorious bloom and see the "seeds" of ruin--the scattered pockets of invasive mugwort, nutsedge, stiltgrass or lesser celandine, crown vetch or Chinese bushclover that without early intervention will quickly expand and ultimately prevail. 

My interventions--a broad mix of successes and failures--have taught me above all that early intervention can make the difference between hope and despair. 

One special garden in town that I stop by to check up on, like an old friend, is the Betsey Stockton Garden planted atop the Firestone Library at Princeton University. This is a complex native planting, containing 35 native grassland species. The person or crew maintaining the garden needs to be able to recognize and identify all 35 intended species, plus all the weeds that could potentially cause problems, not only when they're blooming but at all stages of development. 

That deep knowledge is a tall order. Knowing how little respect maintenance often gets, I worry about this meadow garden in the longterm. Will it receive the knowledgeable, strategic attention it needs to thrive? This photo of wild bergamot blooming with lots of clumping goldenrods suggests things are going well. 

Here, some black-eyed susans lend color, but the pink blooms of quickly spreading non-native crown vetch spell trouble.

New to me is a weed called rabbits foot clover, which may have hitchhiked in from whatever distant nursery the intended plants came from. This, too, was not caught early, and now poses a significant challenge.

Thankfully, there's only one small patch of the fearsome mugwort, but that could quickly expand if not dealt with quickly. Getting as close to zero tolerance for invasives as possible makes maintenance much easier. 

Maintenance is not given its due in part because success is often invisible. In a house, we note dirt's presence, not its absence. A well-run government agency doesn't make it into the news. The bass player who provides the harmonic foundation for a band often goes unnoticed until he plays a wrong note. In medicine, catching problems early doesn't pay as well as dramatically rescuing someone whose problem has grown into an emergency. Extrapolation can help with this. It allows us to see large consequence in small acts, to appreciate how big a problem has been avoided by digging up a small, isolated patch of mugwort.

I found a few relevant local writings. One was an opinion piece in the Daily Princetonian by an undergrad, calling for more native plantings on campus. Planting is a good start, but what goes unmentioned in the opinion piece is that maintenance determines any planting's fate. 

One strategy being used in newer native plantings on campus is to plant gardens with only three or four species, with lots of mulch inbetween plants. This reduces the amount of training required for maintenance. 

Other local writing specifically about the Betsey Stockton Garden can be found in the Princeton Magazine. It includes the list of intended plants (below), and describes the garden as low-maintenance, but that assumes the invasive weeds will be caught early and removed before they can spread.

The Betsey Stockton Garden was planted in 2018, two years after the demise of another campus native planting, around the Neuroscience Institute. Hopefully some lessons are being learned, and the University will bring the necessary expertise and strategic timing for maintenance to bear on this lovely, botanically complex planting. 

Native Plants Featured in the Betsey Stockton Garden
(Some are used on the High Line as well.)

Grasses: Carex comosa, Appalachian Sedge Carex pensylvanica, Pennsylvania Sedge Festuca ovina, Sheep’s Fescue Festuca rubra, Creeping Red Fescue Sporobolus heterolepis, Prarie Dropseed Elymus virginicus, Virginia Wild Rye Schizachyrium scoparium, Little Bluestem Tridens flavus, Purple Top Shade Plants: Aqueligia canadensis, Wild Columbine Aster laevis, Smooth Blue Aster Blephilia ciliata, Downy Wood Mint Erigeron puchellus, Robin’s Plantain Eurybia divaricata, White Wood Aster Polemonium reptans, Jacob’s Ladder Sisyrinchium angustifolium, Narrow Leafed Blue-Eyed Grass Solidago caesia, Blue-stem Goldenrod Solidago flexicaulis, Zig-Zag Goldenrod

Full-Sun Plants: Asclepias tuberosa, Butterfly Milkweed Aster laevis, Smooth Blue Aster Aster pilosus, Heath Aster Baptisia alba, White Wild Indigo Baptisia perfoliata, Catbells Centaurea cyanus, Cornflower Chamacaesta fasciculata, Partridge Pea Coreopsis lancelota, Lanceleaf CoreopsisEchinacea pallida, Pale Purple Coneflower Echinacea purpurea, Purple Coneflower Monarda fistulosa, Wild Bergamot Penstemon digitalis, Beard Tongue Rudbeckia hirta, Blackeyed Susan Solidago juncea, Early Goldenrod

Tent Caterpillars and the History of Black Cherry Trees in Herrontown Woods

Black cherry trees draw attention in early spring because of the "tents" that tent caterpillars weave on them. I was surprised to find out that these tents are sometimes mistaken for gypsy moth infestations. There's also some disagreement as to how damaging tent caterpillars are to the trees they feast upon, so I decided to do some investigation. 

First, some distinctions between tent caterpillars and gypsy moths. Tent caterpillars are native, feed primarily on cherry trees, build conspicuous tents, and do their feeding on the fresh, tender leaves just beginning to emerge in April. Gypsy moths are a nonnative species imported from Europe, start feeding in May on a very wide spectrum of hardwoods and even some conifers, and do not build tents. 

Gypsy Moths

The story of gypsy moths in our area is most easily grasped by looking at how many articles about them have been archived in the Papers of Princeton through the decades. Outbreaks of gypsy moths remained minor in New Jersey until the 60s, then grew into massive defoliations of forests in the 1970s. By the early 1980s, gypsy moth populations were beginning to drop, thanks to a natural virus, introduced parasites, and aerial sprayings. A naturally occurring bacteria called Btk proved safe and effective when sprayed on trees where gypsy moths were feeding. There was a recurrence from 2007-8, but numbers have dropped off since then. Though the forests largely healed, the trauma of past gypsy moth infestations lives on in people's memories. 

Tent Caterpillars

What we have this spring, and springs extending back through millenia, are native tent caterpillars making their tents. 

Some sources on the web suggest that tent caterpillars, despite the powerful visual of the tents and defoliated branches, don't do enough damage to a tree to worry about. I'd really like to believe that, but this young black cherry tree, now bearing eleven tents from which the caterpillars make forays, is almost completely defoliated. 

They say a tree can survive one complete defoliation, but if defoliated several years in a row, it becomes increasingly susceptible to disease and insect attack.

Meanwhile, our very hungry tent caterpillars have even followed a branch over to a neighboring pin oak, which now, too, is getting chowed down upon.

We pause to note a couple recurring themes in nature. One is that the tent caterpillars will shift to a less desirable food source (a pin oak tree) if their favored cherry tree leaves run out. Deer, too, will begin eating less desirable foliage if they run out of their favorites. Thus, an overabundance of deer in the 1990s almost wiped out spicebush in our Princeton woodlands, despite it being low on the list of deer's preferred foods.

The other example of a recurring theme in nature is that the tent caterpillar eats only one crop of leaves, then is done for the year, allowing the tree to recover. The worst thing a predator could do is be so effective as to eliminate its prey. 

The introduction of a new insect, though, could throw off this balance of predator and prey. If another insect, say, a gypsy moth, came along and defoliated the same tree yet again in the same growing season, that tree would be in big trouble, having twice committed energy to manufacturing a whole crop of leaves, only to have them eaten. One question is whether the gypsy moth outbreaks in the '70s and '80s killed more of one tree species than another, causing changes in forest composition still noticeable today.

There's a lot of caterpillar behavior whose purpose is not immediately obvious. A week ago, caterpillars were crawling about on the outside of the tent, turning this way and that. My best guess was that they were expanding the tent by adding another layer of silk, but no strands could be seen coming from their bodies as they moved about. 

And why are these caterpillars clustered on the side of the tree, outside of their protective tents? Wouldn't they be easy picking for the birds that are said to consume them? 

As their spring residency has continued at the Barden in Herrontown Woods, the tent caterpillars have spun not only isolated tents but also enveloped the trunk and limbs in a silken web reminiscent of the webbing people drape on their shrubs for Halloween. A closer look reveals that the caterpillars have spun silken highways upon which they commute from tent to the "pasture" of the canopy. These highways are only one lane wide, requiring a caterpillar to temporarily step aside if it meets another coming the opposite direction. Some silken highways are suspended in air, like overpasses--a great way to smooth out the rough terrain of a black cherry tree's "black potato chip" bark. 

A tree colonized by tent caterpillars, then, has elements of occupancy, transport, and exploitation not unlike the human footprint on the land, with our homes, highways, and farm fields. A big difference being that the tent caterpillar's settlement is seasonal--more like the impact of nomadic tribes than our permanent villages--giving the tree a chance to recover.

Another big difference between tent caterpillars and other builders of shelters--bees, ants, birds, mice, people--is that the caterpillars don't seem to bring anything back to the shelter other than their bigger, well-fed selves. They aren't adults bringing food back to the young. The caterpillars, like super resourceful children, work collectively to raise themselves, then leave the tree on their own to pupate and turn into adult moths. 

A nice writeup about tent caterpillars (Malacosoma americanum) found at ThoughtCo.com states that the broad side of the tents faces the sun, and that the caterpillars make three forays per day, returning to their tents inbetween. That will be something to check out next spring.

Surprisingly, the subject of wild cherry trees in what is now the Barden (formerly a pine plantation) came up more than 50 years ago, in Richard J. Kramer's book about Herrontown Woods. 

"Wild black cherry, which grows to magnificent size in the Allegheny Mountains, is a poorly formed tree in Herrontown Woods, occurring mostly in areas which were recently open fields. Its best growth has been in the pine plantation, where specimens are 30 to 40 feet tall and possibly may develop into good-sized trees. Apparently these black cherries were able to develop along with the young pines after these were planted in the open field. Although the birds do bring seeds of the cherry into the forest, the many seedlings and the few saplings that occur there grow poorly and remain shrub-like."

Gone now are most of the pine trees in the pine plantation, and those larger cherry trees are nowhere to be found. Our 12 little black cherry trees in the Barden, all saddled with tent caterpillars, must be the descendants of the larger cherry trees Kramer describes. Only one large black cherry tree is known to exist now in Herrontown Woods, almost completely free of tent caterpillars, growing next to Veblen House. Have tent caterpillars contributed to keeping the black cherry trees of Herrontown Woods from achieving full size, in the past as well as in the present?

If we wanted to relieve the cherry trees of the spring burden of hungry caterpillars, we could remove the tents and remember to crush the egg masses laid by adult moths on small branches in late summer, as suggested in this useful post about the insect. 

But as insect numbers continue to decline, the role of trees as food for native insects grows in importance. And if the cherry trees remain small, that will allow more sunlight to reach the many wildflowers growing in the Barden. Leaving the tent caterpillars to grow undisturbed can serve as an experiment, to see if they continue to flourish year after year, or if nature's array of predators, pathogens, and parasitoids finally up their game and reduce the burden these trees now bear.

Harrison Street Park: Contrasting Tales of Trees and Wildflowers

Most people drive by Harrison Street Park unawares. It's an old neighborhood park that lacks parking, and so mostly serves those who live close enough to walk there. Whenever I think to stop by this surprisingly spacious park close to Nassau Street, it's to check in on dreams living and remembered. 

One dream is bringing back the American chestnut. We've planted a number of chestnuts around town that are 15/16th native. They were originally crossed with a resistant asian chestnut, then backcrossed with the aim of ending up with a predominantly native chestnut tree that still carries the Asian species' resistance to chestnut blight. Some of these trees have proven susceptible to the blight, but two in particular have resisted the blight thus far. One of these is in Harrison Street Park, nearly 20 feet tall now. 

We also planted two native butternuts there, another native tree that has been marginalized by an introduced disease. It's good to see them thriving and starting to bear nuts. 

There's also an attempt by the town, successful thus far, to keep a grove of ash trees protected from the introduced Emerald Ash Borer, via systemic applications of insecticide. Another small grove of trees was planted through a citizen donation and collaboration with the Shade Tree Commission.

Other dreams for Harrison Street Park, involving wildflower plantings, have not done so well. Princeton Borough had great dreams for this park at one time. In 2006, they hired me to conduct an ecological assessment and write a stewardship plan. Then they hired a landscape architecture firm from Philadelphia to design improvements to the park. Neighbors offered many ideas and expressed many opinions. The old wading pool--a relic from a distant, more sustainable era when kids gathered in their neighborhood parks in the summer--was removed, the play equipment was updated, and a few new features were installed. 

Some $30,000 was spent on new native plantings that looked good for a year or two before going into steady decline. The idea was that neighbors would care for all these new plants. Of course, a drought promptly ensued. Some of the neighbors rose to the occasion to keep the plants going, but the extensive flower beds required more than an initial season of zeal. Neither the borough maintenance crews nor any of the neighbors had the training or interest to keep the flower beds weeded over the longterm. 

This flower bed is now a massive stand of Canada thistle and mugwort. 

The plant with the big leaves is a common weed in the midwest that is showing up more and more in Princeton. It looks like rhubarb, but is in fact burdock. 

There's a swale in the park that receives runoff from a private parking lot next door. These wet, sunny spots can tip the balance towards native species. A friend and I planted various floodplain species--joe pye weed, tall meadowrue, etc--but also planted Jerusalem artichoke, which is a native sunflower species with edible tubers. 

When planting an aggressive plant like a native sunflower, it's easy to believe one will follow up and keep its expansionist growth in check. That's almost never the case. The sunflowers has spread aggressively underground over the years, and have long since swallowed the other wildflowers in their dense growth. Each year the sunflower clone expands, as park crews mow around its fringe. 

We also planted a couple pawpaw trees there, but they were overwhelmed by the sunflowers. A couple black walnut trees sprouted on their own and had much better luck, somehow managing to rise above the sunflowers. Trees that plant themselves tend to be more successful than trees planted by people. On the upside, the sunflowers are so aggressive that they require no weeding, and there's a dazzling display of yellow in the fall. But, like some of the other plantings at Harrison St Park over the years, it's not what was originally envisioned. 

More Bear Sightings in Princeton

Princeton has no resident black bears, but they do occasionally wander through in the summer. There were some sightings beginning Aug. 11 near the old Butler tract, then August 13 in the Herrontown Woods area of northeastern Princeton, then other sightings through August 18 down along the Stony Brook.

The wisdom of a comic description I've posted in the past detailing how Princetonians should behave when encountering a black bear is confirmed in a recent article by the Town Topics. 

Black bears, particularly young males, are motivated to seek out new territory in the summer. One online source describes how young bears stay with their mothers for about 18 months, then are shooed away when the mother receives the persistent interest of an adult male, commencing another cycle of reproduction. 

Each bear must establish a home range. Female bears often share their ranges with their female offspring, but the young males must find new territory. That search sometimes includes Princeton. To get a sense of what the young male bears are looking for, Princeton is roughly 18 square miles, which is on the small side for a male bear's home range. Though we have a lot of open space, the habitat isn't enough to sustain a bear. Thus the brief visits in summer.

There is considerable solitude in the 20 plus years of a bear's life. The females have the recurring company of their offspring for 18 months at a stretch, but adult males spend their time alone except for a periodic few days' courtship with a female.

Black Bear Seen in Princeton

 This notice from the University:

Date:  Monday, June 20

Incident:  Black Bear Sighting

At approximately 2 pm. on Monday, June 20, a black bear sighting was reported on the Lake Campus (300 Washington Road).

Black bears by nature tend to be wary of people.

The New Jersey Department of Environmental Protection has tips on black bears available at https://nj.gov/dep/fgw/bears/index.html

A compendium of previous black bear sightings can be found by typing "bear" into the search box for this blog. They include an explanation of why black bears come wandering our way this time of year, which has to do with young males seeking new territory.

Many people wonder how to behave when a bear is encountered. Below are the fruits of my research, conducted ten years ago and adapted for a Princeton audience. These words are as relevant now as they were then. Please note that grizzly bears, which are not found around here, require a completely different response.

Black bears are near-sighted, so make noise to avoid surprising them. If the bear stands up on its hind legs, don’t worry. It’s just trying to see you better. Make sure the bear has an escape route. For instance, if it is following you out of the public library, hold the door open and give it plenty of room. If you encounter the bear in the woods, or on Nassau Street, you can back away slowly, but don't turn your back to the bear. In a calm, assertive voice, put the bear on notice that you are a Princetonian fully armed with opinions, and will not hesitate to express them.

Avoid eye contact. If it doesn't run away right off, bang the pot you happen to be carrying with you, or download a "kitchenware noise" app on your cellphone. Bears hate to cook, which explains their interest in garbage. Otherwise, clap your hands, raise your arms over your head, wave a jacket, all of which should make you look large and impressive.

On rare occasions, the bear will do a bluff charge, at speeds up to 35 mph. If a cafe is close by, this is a good time to duck in for a double latte. If that option is not available, then you'll need to dig deep. Fleeing will only make you appear weak. Perhaps the stirring words of a high school football coach will come to mind. In any case, stand your ground, wave your arms and shout. Pretend you're in front of town council, venting your outrage over moving the Dinky. The bear should veer away from you at the last moment, providing a bigger thrill than any 3D movie at the mall.

If the bear actually attacks, which is extremely rare, it's time to drop all remaining pretense of civility. Fight back. Don't worry about the bear's lack of access to dental care. Without asking permission, bop it on the nose. Bears' noses are 100 times more sensitive than ours. Use this sensitivity to your advantage, all the while reveling in what a great story this will make to tell the grandkids.

Note: In case you surf the internet for more info, don't be confused by accounts of how to behave when encountering a grizzly bear out west, where the protocol is completely different and not nearly so gallant.

Butternut Redux--A New Generation Bears its First Crop

This has been a breakthrough year for those of us working to bring back the native butternut--a species laid low by an introduced canker disease.. 

Twelve years after I helped Bill Sachs collect one of the last known harvests of native butternuts in Princeton, the new generation has finally born a crop of its own. Butternuts, also called white walnuts, or Juglans cinerea, bear nuts similar in look to black walnuts, but are oval rather than round. 

Bill continued to harvest and plant butternuts from the TRI property for a couple more years, but that pair of trees was then lost, with one blown down and the other cut down, ironically as part of an environmental remediation of contaminated soil. Most of the other known specimens, solitary so unable to bear, at Herrontown Woods and Mountain Lakes, have since been lost as well, lending all the more importance to this new generation of trees, grown by Bill and planted around town. 

We planted multiple trees, for cross pollination purposes, at Mountain Lakes, Herrontown Woods, Harrison Street Park, and at the TRI property where the seeds had originally come from. 

The saplings needed to be caged, to protect them from the deer. I made the mistake of removing a cage when a tree was tall enough that the deer could no longer reach the leaves. Bucks proceeded to rub the bark off the trunk, reducing a promising tree to root sprouts. A post from a couple years ago tells of some of the persistence required to nurse a new generation towards maturity. Along with deer, the young butternuts have been in danger of being smothered by fast-growing Japanese honeysuckle and grape vines, and trees like sweetgums and mulberries that rise quickly to fill the sunny openings the young butternuts need to grow.  Gardening, even wild gardening with native species, teaches the necessity of followup. 

This year, the butternuts had to deal not only with the 17 year cicadas' heavy pruning, but also the expanding presence of spotted lanternflies. 

Adding to the young trees' burden were some galls, which Bill said were most likely caused by walnut leaf gall mites

But despite all of that, the long awaited flowering of this new generation was spotted in July, and a few nuts collected in fall that appear to be viable, offering hope of yet another generation to come.

This fall's harvest is mostly being planted to grow more trees. Bill plants the butternut seed "in tall pots to be kept outdoors for the winter. This has worked well in the past."

Here are some additional tidbits gleaned from correspondence with Bill. The "float test" is used to determine whether a nut is viable. If it floats in water, it lacks a viable seed inside. (Update: This is true if the nuts have just been gathered. Once they dry out, even viable nuts will float.)

Dehusking walnuts and butternuts:

"I don’t really know if it’s absolutely necessary to dehusk walnuts or butternuts before a float test, though I think it is prudent. If you have a lot of nuts the best way to dehusk them is to use an old cement mixer with rocks and water… since I don’t have an old cement mixer, I use a piece of ½ inch plywood about 18 in by 6 in. I put a butternut or walnut in the driveway or street, put the plywood on top and use my foot with pressure to roll the nut under the plywood. (Use gloves to handle the nuts if you don’t want to stain your hands.) The husk comes off pretty easily. Then I put the largely dehusked nuts in a bucket of water and use a still wire brush to complete the cleaning."

Identifying butternuts: "Butternut bark is characteristically a lighter gray with broader ridges than black walnut (but not always). Easier to tell for sure from a twig with a terminal and a few lateral buds. If you slit the twig, butternut will have a dark chocolate-colored, chambered pith, and the leaf scars typically have a hairy fringe (or mustache) along the upper margin. When the leaves are still on the tree the leaf rachis will be tomentose or pubescent (hairy). Not sure if this carries over to fallen leaves on the ground in the winter. Finally, butternut trees often have poor form. In contrast, black walnut has a buff-pink chambered pith, no hairy fringes along the top edge of the leaf scars and the rachis is smooth (among other differences)."

Some additional reading recommended: 

On butternut seed propagation/germination:

https://htirc.org/wp-content/uploads/2020/10/SeedPropagationProtocol.pdf

 

On butternut conservation:

https://www.extension.purdue.edu/extmedia/FNR/FNR-421-W.pdf

In a Hidden Valley, Sudden Abundance, and a White Squirrel

Some of my favorite memories in nature are of sudden abundance. Day to day, walking through a woods or stepping into the backyard, we tend to see one or two of this or that bird or flower. The dispersed, low-key nature we typically see contrasts with accounts from long ago, when endless flocks of passenger pigeons darkened the sky, and herds of bison stretched to the horizon. As a kid, I read of distant streams or lakes teaming with fish. "Where lunkers lurk just below your boat" was one memorable headline. On a few occasions I convinced my father to drive me to them, trips that repeatedly ended in disappointment. 

Serendipity, however, has served up sudden abundance a few times in my life. One fall day early on in my small Wisconsin hometown I was walking home from school when I happened to look up and saw the whole sky filled with monarch butterflies heading south for the winter. There was the small inlet we canoed into in the Quetico, where we happened to look down and saw the shallow water was thick with a school of walleye, from which we quickly caught a delicious dinner. During our time in North Carolina, there was the time when hundreds of cedar waxwings enlivened our neighborhood for a couple days with their antics. And each year in the fall, I'd hope to be around when a large flock of migratory robins, with a few scarlet tanagers mixed in, would descend upon our yard, strip the flowering dogwoods of their ripened berries in an orgy of consumption, then be gone. Even the small park behind our house here in Princeton served one evening a few years ago as a stage for sudden abundance, when winged ants began emerging from the ground, attracting hundreds of dragonflies which in turn attracted a flock of swallows, spectacular fliers all.

This summer, serendipity served up sudden abundance in the most unlikely of places: a hidden valley in Princeton Junction. One afternoon I was standing outside a strip mall with a few minutes to kill, and decided to check out the woods behind the row of businesses. In retrospect, I was just following the flow of the pavement like any self-respecting raindrop would have done, but this going with the flow was taking me away from the human mainstream into another world.

There, beyond the edge of the asphalt, the land dropped down into a woodland like no other I have ever encountered. Perhaps only a botanist would have recognized the extraordinary nature of the nature that stretched before me. Clethra as far as the eye could see. Okay, let me explain. Clethra alnifolia, summersweet, sweet pepperbush, call it what you will, is a native shrub with a fragrant flower sometimes used in landscaping. 

Now, if you're into native plants, you may start to wonder where they typically grow in the wild. Many of the more popular ones--like Clethra, or Virginia sweetspire, bottlebrush buckeye, oak-leaved hydrangia, purple coneflower--have proven rare or non-existent in the wilds I've explored over the years. This could be due to the myriad ways in which we have transformed the landscape, from development to draining to fire exclusion. Or it could be that their home habitat is remote from places I've lived. In the case of Clethra, I had never seen it in the wild save for one sorry specimen holding on next to the towpath along the banks of Lake Carnegie. 

It was a surprise, then, to step behind a pizza joint just up from the Princeton Junction train station, and find myself gazing out on a sea of Clethra, growing like a weed. 

Ostrich fern is another plant I've rarely seen in the wild, and here it too was growing in abundance, giving the woodland a tropical look. 

Returning later with a pair of rubber boots, I waded out into the mud to explore this hidden valley, several times almost losing my boots in the thick muck. 

Here are a few other sudden abundances and rarities--plant, animal, and human--that I encountered:

On the hammocks of high ground surrounded by the mucky soils, Hydrangeas were in full bloom, reaching up to 17 feet tall.

Under a canopy of black gum, red maples and oaks, there were lots of Magnolias

and highbush blueberries.

Netted chain ferns, which bear a resemblance to the much more common sensitive fern, were tucked in among the massings of ostrich ferns.

A small, bent over tree with a curious compound leaf caught my attention. It wasn't a walnut or ash or anything else I could think of. I was excited at the thought that I had discovered a very rare tree, and stumped several botanists before sending a photo to Bob Wells of Morris Arboretum. He promptly identified it as poison sumac--something I hadn't encountered since field botany days in Michigan. The ID explained the skin rash I had been dealing with since handling it.

As with the poison sumac, there was just one Styrax, which showed the remains of its pendulant flowers, and one native azalea. All of these are rarely seen in the wild.

Only towards the other side of the valley did it become clear why this habitat was so different from what can be encountered in Princeton. Most of the stormwater runoff from the strip mall is somehow channeled to the far side of the valley, where it has eroded the stream and exposed the underlying gravel and sand. Simply by crossing Route 1, I had left the piedmont clay of Princeton and entered NJ's sandy inner coastal plain. Though erosion has changed one side of the valley, the other side is fortunately bypassed by the runoff, allowing the mucky soils and hammocks to persist in something close to their pre-development state.  

I had just counted my 30th wild hydrangea blooming in the valley when I saw a man with a white beard walking down into the woods. Scampering about 30 feet ahead of him was a white squirrel. I had already encountered so many unusual plants in this valley, and now I was seeing a white squirrel for the first time in my life. It's distinct appearance lent magnificence to its every move, as if a spotlight were upon it. This photo is the best I could manage with my cell phone as the man continued down the slope. The white squirrel can be seen in the lower right corner. 

He didn't seem to notice me, so I called out to ask him something about the squirrel. He turned and began telling me about a white squirrel he had befriended some years back. It had been a true albino, with pink eyes, and he had trained it to come to him for food. It had gotten to the point where it would come inside. He said that he'd start opening the door for the squirrel to go in his house, and the squirrel would push it further open and come in. He said the true albinos supposedly can't see as well, and that's one reason why it might have allowed itself to be tamed. One day it disappeared, and a friend told him it had been hit by a car. 

The white squirrel I had just seen was one of the albino's offspring. Actually, he explained, they are called silver squirrels, because they have a little gray on their backs, but are otherwise white. Squirrels are really smart, I interjected, expecting him to marvel at how remarkable squirrels are, but my thoughts on their intelligence made him think instead of how you can't keep them out of a house, and how squirrels had gotten into an old neighbor's attic and nearly destroyed her house. He was clearly not one to romanticize animals.

I asked him if this hidden valley is protected, and he said they have had to fight to keep the developers out of it. They lost about 60 feet of it when the strip mall developers wanted to build off the back. Lots of trees lost. He later said there's no organization, just the neighbors who border the property. He had a t-shirt on that said "REAL MEN DON'T NEED INSTRUCTIONS". I asked to take a photo of the shirt, as an excuse to photograph him. He said yes, and pointed out the hammer on the shirt, accidentally cut in two by a table saw. His name was John.

We walked down to the stream, where he said there had been a bridge that got washed out. The bridge turned out to be a long timber, 8x8, which he lifted back into place with some effort, but still impressive for his age. He said the neighborhood is called Berrien City. 

I told him how amazing this valley was for a botanist like me. He said when he'd first heard about the house they bought, and heard it was in Princeton Junction, he pictured something urban. But finding this valley behind it changed his mind. He asked if I'd seen the pond, and when I said no he offered to show me. 

As we maneuvered through the woods thick with sweet pepperbush, he began telling me about his early days, living on the outskirts of Langhorne, PA. He had wanted to be off the grid back then, bought a house that hadn't been lived in for 30 years, had a hole in the roof, one bedroom, a living room and a kitchen. They had a 2 year old son. Their water came from a spring up the hill. A number of them living there dug underground pipes to direct the water to their homes. He said he was at the bottom of the line, and had 600 feet of regular garden hose that the water flowed through to get to his cisterns--one of concrete and two of stainless steel. The cisterns were always full and overflowing, and to keep the water flowing through the hose in winter he had to keep the faucet open in the kitchen. If the hoses froze, he had to gather up all 600 feet and bring them in next to his woodstove to thaw out. He heated completely with wood until their son was seven. The house had 30 amp service, and there was some sort of radiant heater he could turn on to warm the outhouse seat before he headed out there in the winter. They heated water on a stove, and bathed in a tin tub in the kitchen. They ate squirrel and raccoon. The raccoon, he said, actually tasted good. A possum they tried, though, tasted like a McDonald dumpster. He still chops wood. His son, a policeman, still heats his house with wood, even though they have a regular furnace. His son uses a woodsplitter, though. 

The subject of raccoons got him talking about how he used to pay his mortgage with roadkill. Raccoon pelts fetched $50 back in 1980, and fox $75. He'd keep them in his freezer, skinned or sometimes not, until he had enough to make a delivery. It didn't take many to come up with 300 bucks. 

John told me more stories as we stood next to the stormwater pond, in this otherworldly valley hidden behind the loading docks and clustered storefronts of a strip mall that looked like any other in America. I wished I had turned on my phone's recorder to capture his voice and more fully document his story. Much of it involved his life in the fur trade in the 1980s, driving fur traders along a circuit from NY City out to North Carolina, north to Ohio and Pennsylvania, then back to New York, sometimes with $100,000 worth of furs in the back of the truck. It sounded like an updated version of trade in the 18th century. As a line of work, it probably met its demise in the 1990s, when animal cruelty concerns came to the fore. And I doubt a mortgage could be paid off in the 21st century with roadkill. 

Heading back to my pickup afterwards, as if to bend my mind once more before emerging from the woodland, I saw another white squirrel, or perhaps the same one, racing up a tree.

The Very Dramatic Caterpillar Eating Wild Blueberry Bushes

Before I saw the blueberries, I saw the caterpillars eating the blueberry bushes. They were distinctive in the braiding of their bodies into a cluster on the stem. I snapped a photo of their distinctive black heads, yellow necks, and striped bodies, and must have brushed against the bush, because when I looked at them again, surprise!

They had all contracted their bodies into a dramatic pose that completely hid their heads, as if they were the caterpillar world's equivalent of a synchronized swim team. What's the logic here? Look down and away and the potential threat will disappear? Seems human, somehow--a caterpillar's artistic pose to symbolize society's head-in-the-sand response to climate change.

A nearby bush had been stripped of leaves but still had a few blueberries.

While highbush blueberry bushes tend to be solitary, the lowbush blueberries I have seen in woodlands, whether in North Carolina, on top of New Jersey's Mount Tammany, or in Princeton's Herrontown Woods grow clustered in colonies on a hillside.

These heavily shaded patches and the measly crop they bear seem to me stunted remnants of a past glory, when periodic fires would sweep through, thinning the canopy and setting the stage for a burst of new growth from the resilient roots of the blueberries, which then prospered in the partial shade of the scattered trees. Thick bark and decay-resistant leaves are common traits of trees that are adapted to periodic fire. Oaks exhibit these traits in Princeton, their leaves persisting on the ground as fuel for fires that no longer come.

The most dramatic example of the distortion caused by fire exclusion that I've witnessed was in a woodlot preserved as part of Bennett Place, a Civil War site in Durham, NC where the war's largest surrender took place. In the past, trains passing close by would throw sparks, causing low-burning fires to sweep through the woodland, promoting the growth of fire-adapted post oaks and shortleaf pine. I like to call these rejuvenating events "mildfires"--the relatively tame wildness of a healthy nature--in contrast to the destructive wildfires we're used to hearing about in the news. The woodland--perhaps more like a savanna--was a favorite place for Duke University botanists to find a rich understory of wildflowers prospering in the open shade. As they remarked on this or that rare species of wildflower, they must have sampled the berries from the broad patches of blueberries that persist there. As trains have become less sparky, and people more fire-averse, the less fire-resistant, fast-growing trees like willow oaks have grown up, while the deepening shade and the accumulation of unburned pine needles have stifled the wildflowers. The once-thriving "fire-climax" ecosystem is begging for a fire that never comes, as the old trees slowly succumb.

Though the exclusion of periodic fire has also made Princeton's woodlands less natural, we can see in the caterpillars' partial munching--some shrubs eaten, some not--the persistence of another aspect of balance in nature, worked out over millenia of coevolution. No species can survive long if it wipes out its food source. Long-term stability thrives on balance. New species introduced from other continents lack these elaborate checks and balances. Stiltgrass smothers large swaths of Princeton's preserves because nothing eats it. Our forests have suffered a series of shocks, from chestnut blight in the 1920s, gypsy moths in the 1970s, and now the emerald ash borer--all from introduced species that lacked the checks and balances that evolve over time.

The common name for our very dramatic caterpillar, "contracted datana," is hardly a common name given how few of us have heard of it, and is merely an adaptation of its latin name, Datana contracta.  Come to think of it, the heads of the caterpillar look a lot like blueberries. Their collective ducking seems to be saying to a hungry predator, "Please move along, no food here!"

Young Black Bear Spotted in Princeton

Seen in Herrontown Woods yesterday, Saturday, July 2, the black bear was moving through town today, and was on Fisher Ave (near Harrison St and Hamilton Ave) around 8am. The police and animal control officer are aware, and say that the bear is not aggressive. The PlanetPrinceton facebook page is a good place to get updates.

It's a good time to brush up on etiquette for black bear encounters. How you should respond to a black bear is completely different from the recommended response when encountering a grizzly bear out west.

This is serious business, of course, but after reading the state's recommendations, which call upon us to exhibit considerable self-control and courage, you can find below a comic version customized for Princetonians, which I wrote in 2012 after a presentation on black bears at town hall.

At the presentation last month on black bears, given by state officials in township hall, I was astonished to learn that, in the very rare case that a black bear attacks, the best tactic is to fight back. Princetonians have not been called upon to display such courage since 1777, when we all could conveniently claim we had yet to be born. 

To bridge this gap between experience and expectation, I herein provide a translation of the wildlife officials’ instructions, customized to fit the Princetonian lifestyle:

Black bears are near-sighted, so make noise to avoid surprising it. If the bear stands up on its hind legs, don’t worry. It’s just trying to see you better. Make sure the bear has an escape route. For instance, if it is following you out of the public library, hold the door open and give it plenty of room. If you encounter the bear in the woods, or on Nassau Street, you can back away slowly, but don't turn your back to the bear. In a calm, assertive voice, put the bear on notice that you are a Princetonian fully armed with opinions, and will not hesitate to express them. 

Avoid eye contact. If it doesn't run away right off, bang the pot you happen to be carrying with you, or download a "kitchenware noise" app on your iphone. Bears hate to cook, which explains their interest in garbage. Otherwise, clap your hands, raise your arms over your head, wave a jacket, all of which should make you look large and impressive.

On rare occasions, the bear will do a bluff charge, at speeds up to 35 mph. If a cafe is close by, this is a good time to duck in for a double latte. If that option is not available, then you'll need to dig deep. Fleeing will only make you appear weak. Perhaps the stirring words of a high school football coach will come to mind. In any case, stand your ground, wave your arms and shout. Pretend you're in front of town council, venting your outrage over moving the Dinky. The bear should veer away from you at the last moment, providing a bigger thrill than any 3D movie at the mall. 

If the bear actually attacks, which is extremely rare, it's time to drop all remaining pretense of civility. Fight back. Don't worry about the bear's lack of access to dental care. Without asking permission, bop it on the nose. Bears' noses are 100 times more sensitive than ours. Use this sensitivity to your advantage, all the while reveling in what a great story this will make to tell the grandkids.

In case you surf the internet for more info, don't be confused by accounts of how to behave when encountering a grizzly bear out west, where the protocol is completely different and not nearly so gallant.July, 2012

Native Trees of Princeton

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

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

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

ATTRIBUTES OF SOME NATIVE TREES IN PRINCETON 

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

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

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

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

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

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

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

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

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

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

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

Carya alba (mockernut hickory)

Carya cordiformis (bitternut, swamp hickory)

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

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

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

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

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

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

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

Fagus grandifolia var. caroliniana (beech)

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Prunus pensylvanica (fire or pin cherry)

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

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

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

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

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

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

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

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

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

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

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

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

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

Ulmus rubra (red elm, slippery elm)


Native Evergreen Trees:

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

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

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