Friday, March 30, 2018

Princeton Battlefield Clean-up -- March 31

Each year, the Princeton Battlefield Society and the local chapter of the Sierra Club team up to have a volunteer workday at the Battlefield. Though the Battlefield is a state park, the state limits its maintenance of the grounds to lawn mowing, leaving the rest of the park's greenery to grow as it may. Two very aggressive introduced species, bamboo and porcelainberry, have run rampant, impinging on trails and overwhelming some historic plantings such as the dogwoods planted in 1976 to celebrate the nation's bicentennial. As part of the Friends of Herrontown Woods' outreach, I'll be leading volunteers interested in sustaining the dogwoods planted around the perimeter of the park on the Colonnade side.

Anyone who'd like to join in, check out the flier below, and rsvp at If you can, bring workgloves, loppers, and handsaws. Here's a writeup on last year's spirited event, with our state senator Kip Bateman in attendance.

Thursday, March 29, 2018

A Pretty (scary?) Snake in the Basement

Earlier this week, I received the photo below in an email entitled "Copperhead?". The email was from Robert Socolow, a distinguished physicist at Princeton University. He usually focuses on climate science, but this past weekend his focus was drawn to an unusual snake he found in his basement up on the Princeton Ridge. This particular snake subsequently met its demise, but the thought that it could be a venomous copperhead snake made him leery of spending any more quality time in his basement.

My first guess was a corn snake, but we needed more than a guess. I sent the photo to my friend Perry in Durham, NC, where I used to see copperheads now and then in my old stomping grounds along Ellerbe Creek, their heads above water, gazing upstream.  He in turn sent it to his friend and Duke University biologist, Ron Grunwald.

The answer came quickly: Eastern milk snake, nonvenomous. They're said to be fairly common. According to the wikipedia page, they are a kind of king snake that can be found in various habitats, including rocky slopes (the Princeton Ridge), and also in barns. Their presence in barns may be the reason a myth arose that they suck milk from cows, which anyone who knows snakes and cows will agree is udderly ridiculous.

Rob was relieved, but the episode begged the question: Are there venomous snakes in New Jersey? The answer to that came very fast, when up popped the website for Conserve Wildlife Federation of NJ, and a post on the northern copperhead (affectionately known among herpetologists as Agkistrodon contortrix mokasen). For anyone thinking of copperheads as a southern species, it's a surprise to learn that the northern copperhead's range actually begins north of Princeton, extending from the Sourlands up through northern NJ.

The range of the one other venomous snake in New Jersey, the timber rattlesnake, conveniently avoids Princeton, with populations both north and south. The scientific name for this snake is Crotalus horridus horridus, which seems unscientifically judgemental. 

For the curious, there's a nice-looking pamphlet of New Jersey snakes at this link

Thanks to Rob for sending the photo, and to Ron for the identification. Though the snake may well have been doing a fine job limiting the number of mice and camel crickets in his basement, Rob was understandably prompted nonetheless to reaffix the screen that had fallen off a drain pipe leading from his basement to the great outdoors.

Friday, March 23, 2018

Monarch Butterfly Populations Down

Last year, monarch butterflies numbers were up in the Princeton area compared to previous years, but those heartening visits in our gardens and along roadsides did not translate into increased numbers at their overwintering grounds in Mexico.

The announcement of an official count was delayed this year for some reason. Numbers for the western population of monarchs, overwintering in pine and eucalyptus groves in southern California, came out a month earlier, in early February, and were down considerably. Finally, early this month, the announcement came that numbers of eastern monarchs have declined again. They've been lower the past two years, after small increases the two years prior, with 2014 having marked an all-time low. Over the past several decades, the overall trend has been down, with overwintering monarchs filling 44 acres of forest in Mexico in 1997, and only 6 acres this year.

So many factors affect the survival of monarchs. Illegal logging, windstorms, and coldsnaps can affect their overwintering success. This past fall's migration was affected by the series of tropical storms and the unusually warm weather that delayed the monarchs' flight south. Increased use of herbicides for farming genetically engineered crops has decimated the milkweed that monarchs need to reproduce. And then there's the looming hammer of climate change, as political and economic forces keep us trapped in dependency on fossil fuels. We see, in car commercials, town streets and new developments an ever expanding arsenal of exhaust pipes and chimneys aimed at the heart of nature.

There's some good news to mention. Gendarmes (armed police) have reportedly greatly reduced illegal logging in the monarchs' overwintering forests this past year. And people are showing an interest in planting and caring for milkweed. The stunning thing, which for the most part settles in the back of our minds, unthinkable but inextricable, is that the future remains optional.

While the world continues on its path of self-destruction, we can still find pleasure and joy in working with nature, and wonder why so much of humanity just "doesn't get it." This year, I'll be helping create a large native wildflower garden near the parking lot at Herrontown Woods. Except for a few spots like Tusculum, Princeton's open space is mostly forested, and so offers few flowers in summer and fall to sustain pollinating insects like the monarch. But the combination of windfall from storms and the clearing of invasive woody plants has created a clearing at Herrontown Woods that we can now plant. The aim is to replicate my backyard native garden in a publicly accessible space and on a larger scale, with signage so that people can become acquainted with Princeton's native flora. Much of my backyard garden is in turn modeled on the native flora to be found along the canal next to Princeton's Carnegie Lake. Anyone interested in helping the Friends of Herrontown Woods with this project can contact me through this website.

There's also a citizens' science initiative at this link, where you can provide data on monarch sites to a national survey.

Wednesday, March 21, 2018

Memories of a Naturalist--Tonantzintla, Mexico

Google''s celebration of Mexican astronomer Guillermo Haro's birthday today brings back memories of traveling to Tonantzintla, Mexico, where Haro did much of his observing. He was the first Mexican astronomer to be elected to the Royal Astronomical Society. My father, a contemporary of Haro's, took the family along on one of his observing runs, probably to use the same Schmidt telescope. There was some overlap in their work, and some correspondence between them in the late '50s, early '60s.

One perk of being the son of an astronomer is occasional trips to dry, mountainous parts of the world. Whether the destination was McDonald Observatory in Texas, Kitt Peak in Arizona, or Tololo in the desert of northern Chile, I was free to explore the mountainsides all day.

Five years ago, when my family traveled to Mexico City, we made the two hour drive over to Tonantzintla to have a look. I tried to overlay the pale fragments of boyhood memories onto the landscape as it is today, with mixed success.

This might be the yard where my brother and I had two burros to ride around on for the week. My brother's was white, and stubbornly held its ground as my brother pulled on the rope, wanting to take a ride. Mine was smaller, brown, and much more cooperative. Rising in the distance was an impressive mountain with the fun, rhythmic name Popocatepetl. Po-po-ka-TEP-e-tl may have been one of those words that my dad liked but which often got caught in his mouth, struggling to get out.

This may be the cottage where we stayed. The most vivid memory is the smell that emanated from the kitchen when my mother first cranked up the dusty stove to heat water for tea.

Come to think of it, visits to such places in childhood, small enclaves of buildings devoted to scientific study surrounded by nature's splendor, and the feeling of walking into a cottage that may have stood empty for weeks or months prior, may have been the template that gives the Veblen House and Cottage in Herrontown Woods such power. I recently met a woman walking her two dogs in Herrontown Woods who likes it there so much in part because it brings back memories of walking through the woods to her grandmother's house when she was a kid.

Other memories from that childhood trip to Mexico include extended practice sessions with a wooden ball and cup game in a city apartment while my father and brother were recovering from a case of Montezuma's revenge, and an embarrassing I-cannot-tell-a-lie moment when my brother was trying to sneak some fireworks through customs. Not knowing there was anything illegal about it, and with a journalist's instinct for thoroughness, and always having been encouraged to speak up if I had the answer to a question, when the official asked us if we had anything else to declare, I proudly declared, "Fireworks!"

Monday, March 19, 2018

Lou Jost--Finding New Orchids in the Ecuadorian Andes

Last month I found myself standing in a small circle of botanists, talking about new plant species being found in the mountains of Ecuador. Hosting the gathering was John L. Clark, who has gained a very long title since moving to Princeton a few years ago: the Aldo Leopold Distinguished Teaching Chair, Environmental Science and Ethics at Lawrenceville School. John hosted the gathering so that we could meet a friend of his, orchid expert Lou Jost, who lives in a secluded valley in Ecuador.

The latin names were flying while my mind floated back to the last time I had the pleasure of so much botanical company. It was a similar circle of botanists, standing not in a Princeton living room but in a field at Bennett Place, the site of the biggest troop surrender of the Civil War, on the outskirts of Durham, NC. At our feet, embedded in the thin layer of moss that covered much of the ground, was a tiny carnivorous plant, no more than a couple millimeters across--a sundew growing far from its normal range, improbably surviving in an otherwise urban landscape in the North Carolina piedmont. Bennett Place's site manager, who had been unaware of the unique plant life in the field next to his visitors center, was puzzled and amused at how a group of botanists could stand out in the middle of a field, gazing at the ground and talking at length about what for him seemed just a patch of grass. But that's what a love of plants does: it makes the world an endlessly fascinating place.

Lou Jost, our orchid expert visiting Princeton, lives in the mountains west of the Amazon rainforest. His remote home includes a view of an active volcano that periodically spouts lava, visible at night as brilliantly illuminated strands flowing down the mountainside. John got to know Lou back when John was doing research in another area of Ecuador, in similarly remote forests to the north and west, a remarkable experience he spoke about earlier this year at DR Greenway's Johnson center.

Listening to them talk is like a salve for me, allowing relief from the grim news stream most of us wade through each day, of political and economic tensions where nature and its future are relegated to a tiny asterisk. What a pleasure to linger for a time in a world where plants and nature's beauty and endless creativity occupy center stage.

Both Lou and John have worked in areas of burgeoning diversity, where a hike up a seldom trod mountainside can bring encounters with so many species new to science that the samples collected accumulate for lack of time to name and describe them all. These rewards of discovery do not come easily, however, since the forests they explore have survived in part because they are so hard to reach. A new species may be growing 100 feet up in a tree, requiring a dangerous ascent to document. Lou has begun using drones to search the forest canopy, but has yet to come up with a design that can also pluck a sample while hovering next to the tree.

Lou has found dozens of new species in his area of the mountains, where each valley has a distinct microclimate due to the mists rising westward, up from the Amazon towards a high desert plateau. The gradient from east to west, moist to dry, low to high, creates a vast variety of conditions that promote specialization, and the side valleys provide the isolation for speciation to occur.

The joy of discovery can be mixed with sadness, as these explorations of remote terrain have been spurred in part by the threat of farms and expanding villages that now rise like a far less beneficent mist, higher and higher into the mountains. Even steep mountainsides can be farmed, for a curious crop that looks like a yellow tomato.

To save this unique part of the planet, more diverse than the Amazon, Lou started a foundation, Fundacion EcoMinga, to acquire and preserve these forested slopes. New orchid species are often named after donors. Some of the former land owners have become guards. Because there is very little violence in this area of Ecuador, the guards carry cameras rather than guns, to photograph flowers and wildlife as they walk the property. This video of a short talk Lou gave at a World Land Trust symposium gives a flavor of his heroic work, and also gave me an idea for a tweaking of the U.S. Constitution that could lead to a more peaceful world: "the right of the people to keep and bear Cameras, shall not be infringed."

Glorious photos and artistic renderings by Lou can be found on his website at, and here's an article about his discovery of the world's smallest orchid. Interestingly, Lou has no professional degrees, but that hasn't kept him from publishing widely in professional journals. They are looking for content, not pedigree, and an academic degree doesn't bestow the passion and persistence required to explore these remote areas of the world.

Friday, March 09, 2018

Collecting Live Stakes for Propagation

Some species have already sprouted, as many people discovered when branches packed with the flowers of silver maples fell to the ground under the weight of this week's snow. Their blooms are so discreet and elevated that, if not for the jumble of branches littering people's yards, no one might have noticed.

One branch, falling 50 feet from a tulip poplar, scored a direct hit on an old kiosk at Herrontown Woods that hadn't been used for twenty years.

People may not be feeling much affection for branches right now, but here are some stems, collected before the storm, that hold great promise. Called "live stakes," they can be pushed into soft ground to make new shrubs from old.

Elderberry is one of a select few native shrubs that will sprout roots and leaves after a cut section is stuck in the ground. In the wild, they grow in sunny spots in floodplains, and have big plates of white flowers in the summer. The berries are delicious in jellies and pies, and their abundance can overwhelm even the appetite of the catbird that otherwise steals all our backyard fruit crop.

Another is silky dogwood, related to flowering dogwood but less ornamental. It, too, grows along the canal, and can be selectively pruned so as to leave the original shrub intact but yield some nice live stakes for planting elsewhere. This stub was left not by us but by a hungry beaver living in Carnegie Lake.

Buttonbush, with its golfball sized blooms that are eagerly bumbled over by bumblebees in summer, is another super-easy shrub to propagate in this manner. These we'll harvest not from wild populations but from specimens that were planted as live stakes years ago in raingardens around town.

Encountered in the process were some blooms of skunk cabbage. The small, roundish green leaves are the first emergings of lesser celandine, also called fig buttercup, which is a nonnative plant poisonous to wildlife that invades valleys and yards, seducing with its pretty yellow flower before completely taking over.

A nice find, though not for live staking, was the swamp rose (Rosa palustris)--a native rose with larger hips and less vicious thorns than the ubiquitous multiflora rose. It needs more stable hydrology than the nonnative multiflora rose. Given historical draining of swamps, eroding of streams, compacting of ground, and other factors that have reduced infiltration and lowered the water table, the swamp rose is now found in only a few places in Princeton. Its species name, "palustris", is used to name many species found growing in marshy ground.

The live stakes will be pushed into the ground at a couple places where we've converted detention basins to native wet meadows, and also at Herrontown Woods next to the parking lot, where we are creating a place where people can see and learn to identify the native plants of Princeton.

Monday, March 05, 2018

Walking a Stream in Herrontown Woods

The main stream at Herrontown Woods is probably the cleanest in Princeton, thanks to the Veblens
original gift of land, and the champions of open space who followed, ultimately preserving this stream's headwaters. More photos at the Friends of Herrontown Woods website: Soul Made of Wood, Rocks, and Water.

Many boulders bear the shells of hickory nuts, as if squirrels find the stream a good place to picnic.

Sunday, March 04, 2018

What's With the Witch Hazel?

Previous years' posts about the witch hazel growing along Shapiro Walk on Princeton campus were from mid-March. These photos are from late February, when the blooms had likely already been out for a week.

These are not the native witch hazel, which blooms in late fall, but are most likely a cross between the Japanese and the Chinese species (Hamamelis japonica × H. mollis).

It's hard to fully rejoice in their blooms while walking by in a winter hunch.

A few flies showed up for the party, but there were no bees to be seen.