Towpath Sights and Insights

A few recent sights and insights along the DR Canal. A man and his dog, a turtle on a log, (you'd think) a frog,

an east coast greenway.org, of which the towpath is a part, reaching from Maine to Florida,

a wildflower smorgasbord, of climbing hempvine with nothing but itself to climb upon,

a good year for JoePyeWeed,

and a too good year for porcelainberry, which looks like a multi-colored wild grape

and acts like kudzu,

through which towering cutleaf coneflower can still penetrate in places.

Did I forget insights? Well, there's some human manipulation behind all of this nature and nature appreciation. The wildflowers are enabled by a state parks mowing crew that mows the university-owned field just upstream of Harrison Street once every year or two in the dormant season, and keeps the nature trail loop through the field clear.

And then there's the missing insight, of how to keep the porcelainberry from eventually sweeping over that beautiful spot beneath scattered oaks where the JoePyeWeed, ironweed and goldenrod flourish.

Development May Threaten Tranquility of Herrontown Wood

There's a bit of a shock awaiting anyone who takes the short trail from the Herrontown Woods parking lot down to the rock-lined stream. Ribbons of different colors are now wrapped around trees; survey stakes mark points with significance unknown.

There's a strong feeling of invasion in a landscape thought to be safe from intrusion. Take a look at a map, however, and you see that what was assumed to be part of the park in fact is not. In the lower middle of the map is the parking lot, with a small portion of the driveway leading in at the bottom, to the right of "3.02". To the left, you can see that where the two streams meet is actually in a separate parcel. That long sleepy parcel of 10+ acres fronts on Snowden Lane across from Smoyer Park, and was recently purchased.

Thus far, I've contacted town staff and the Friends of Princeton Open Space. Stream buffer requirements (probably 50 feet on either side) may protect the space between the streams from development. The steep slope (evidenced by the topo lines being crowded together) may limit development in the upper left. But all of this is speculative, and doesn't rule out the possibility that one of Herrontown Woods' prettiest and most peaceful stream crossings could be compromised by housing construction.

Note: That trail, by the way, was blocked for a month or two by a fallen tree. Word got to volunteers Kurt Tazelaar and Sally Curtis, of Friends of Herrontown Woods, who spent a couple days clearing the blockage. If you like to "like", or want to read more about Herrontown Woods and the Friends group, check out the Friends' facebook page, and also various posts at VeblenHouse.org.

Below are the various ribbons and stakes encountered.

Wildflowers vs. Mowed Turf in Smoyer Park

There's a theme emerging in Princeton's parks, schoolyards and other public properties: How to sustain wildflower plantings in landscapes dominated by mowers? The bulldozing of the raingarden at the Housing Authority's Spruce Circle on Harrison Street was the most dramatic example of an ongoing struggle.

For instance, a friend contacted me earlier this week, upset about wildflowers that were mowed down next to the pond in Smoyer Park. They had been allowed to grow all summer, then suddenly got mowed about a week ago.

Town staff emailed her to explain that state regs force them to mow. 

• N.J.A.C. 7:20 Dam Safety Standards the dam must be regularly maintained and woody vegetation (trees) cannot be allowed to establish on the upstream or downstream faces of the dam. 
• Additionally, in accordance with the State-required Operation and Maintenance Manual for this Dam, the upstream and downstream sides of the dam shall be mowed monthly between April and October. This is to ensure that woody vegetation does not get established, but also allows us (the Dam Managers) to visually observe erosion, damp or soggy surface, settlement, cracks, animal burrows, debris, groundwater seepage, or other unsafe or unusual conditions.

The park's maintenance was recently switched over to the parks and rec. department, which apparently contracts out for mowing services. The contracted company had not been aware it needed to mow the dam, so had allowed the wildflowers to grow until now--thus the dramatic change in mowing regime. 

The logic of mowing here is questionable. First, there's all the grass clippings that are now rotting in the pond, eating up oxygen in the process. And though monthly mowing allows easier inspection of the dam for erosion, is it really being inspected monthly? This is a big dam on a small pond, built a few years ago to strict specifications. It's hard to imagine that such an impressive edifice could be threatened by a few wildflowers. Is the policy driven by evidence or ideology? Additional areas along the Smoyer Park pond's edge, far from the dam, were mowed as well, probably knocking out swamp milkweed that serves as a food source for monarch butterflies.

A bit of irony, here. Though regulations are aimed at preventing tree growth on the dam, the one tree growing on the dam was left standing by the mowing crews.

If one's worried about erosion, it would be better to mow less often, given that mowed grass has less energy to sustain a healthy root system. I had never seen the old dam at Mountain Lakes Preserve get mowed, and yet it remained intact for 100 years while holding back far more water than can be found in the little pond at Smoyer Park.

It's common, of course, for one government agency to promote its mission to the max (in this case, dam safety) at the expense of another, e.g. habitat enhancement and beautification. Another example of this, found not at Smoyer Park but along the natural gas pipeline, is described in a previous post about the planting of a highly invasive exotic called Chinese bushclover in the name of erosion control.

Meanwhile, riding home from Smoyer Park, I stopped by Little Brook Elementary to see how the nature trail is doing there. It's a wonderful trail through the woodlot where a tributary of Harry's Brook flows through the school's property.

While Smoyer Park is arguably getting more mowing than it needs, the trail at Little Brook Elementary has become overgrown for lack of attention during the summer. This isn't surprising during the summer when the school is closed, but even during the school year, its care remains uncertain.

Even though it is used for educational purposes, and the grounds crews can sometimes find time to do some clearing, maintenance is largely dependent on new parent volunteers coming forward each fall. I know, because I was one of the parents while my daughter was at Little Brook. 

There are, then, multiple factors working against the survival of wildflowers in the town landscape: policies biased towards turf, miscommunication, habit, the lack of plant knowledge and awareness among those delegated to maintain plants, and the built-in uncertainties of volunteer initiative.

Consider that, as Princeton goes, so goes much of the rest of the country, and it's small wonder that people are unlikely to encounter the beauty and diversity of native plants in their daily lives, and that pollinators like the Monarch are struggling.

A Morning of Music, Young Minds, and a Monarch

Last month, Martha Friend, the science teacher at Little Brook Elementary who is also very active in summer programming for kids in Princeton, sent me an email in August asking if I could drop by the Pannell Learning Center and do a program on music and nature with some kids in a YMCA camp. I had never heard of the Pannell Center, which is at the corner of Clay and Witherspoon, and wasn't sure how to incorporate music into nature study, but showed up with an open mind and a clarinet.

The kids, under the motivating guidance of class teacher Rosie, had just finished building musical instruments using straws. After hearing their impressive musical offerings from the straws, I explained that I had learned to improvise on clarinet while out in nature, sitting on the steps of a lodge overlooking Lake Michigan, playing a note and listening to its echo come back from a nearby hill. Later, on Ossabaw Island off the coast of Savannah, Georgia, I learned to play one handed so that the other hand was free to swat mosquitoes. It was an early lesson in the challenges of the music business. I told them about the piano tunes I'd written using birdsongs, and demonstrated a few on the clarinet. That was a good segue to head out towards Community Park School to see if there were any birdsongs I could imitate. Lacking any birdsongs along the first few blocks, I filled in with When the Saints.

While we passed by some interesting habitat--a concrete turtle that apparently found the astroturf to its liking--Rosie told me how she had gained a love of nature during visits to her grandparents' farm in Mexico, where she was put to work caring for the animals.

The kids ate lunch while I sought to channel a field sparrow's call through the clarinet. Then we asked the question, where do the pollinators find their lunch? Not much in the lawn beyond a few white clovers. We walked behind the school to where the Community Park Elementary's science teacher John Emmons has planted a miniature meadow.

That's where we saw lots of pollinators feasting, including a monarch--a rare sight this summer. (That's what the kids are looking at in the first photo.)

The back of the school is surrounded on three sides, making a courtyard where there's a lot of growth energy. Even the weeds in this photo (pilewort that not only grows on the ground but also one floor up on the wall) are looking good. Pilewort is a native weedy-looking plant that grows tall and fleshy but whose only ornamental offering is clusters of white seeds that the goldfinches take a liking to.

A plaque in front of a butterfly house expresses the connection between the growth of inner and outer nature.

During the school year, Rosie teaches an after school program called PrincetonYoung Achievers.

After such an inspiring morning spent with the Y kids in a landscape that is nurturing of inner and outer nature, it was time to head home, stopping by the raingarden at Spruce Circle to find it.....bulldozed! Life comes with its mixture of highs and lows.

Milkweeds Mowed at Tusculum

An earlier post entitled Searching for Monarchs in Princeton mentioned spotting a monarch in a field packed with common milkweed over at Tusculum--the former estate of John Witherspoon on Cherry Hill Road. Here's what that field looked like a month ago.

And here's what that field looked like just a week or two later. Now, some of the fields at Tusculum are publicly owned, while others remain in private hands. This field is privately owned, and has for decades been managed for hay production. That's a big reason why it's still a field rather than a deeply shaded woodland where milkweed would have little chance to grow.

So the annual mowing can generally be thought of as beneficial, but the timing of it--while monarchs are still in our area, reproducing in preparation for their imminent migration back to Mexico-- is definitely not. I doubt that the current owners or the mowing crew had any idea that the field was important monarch habitat, and that waiting a couple weeks would have saved any monarchs maturing in the field.

It's another example of how important it is to communicate with those who own or manage habitat around town.  I've been told that the owners in this case will be contacted, with the hope of shifting the mowing regime next year to benefit the monarchs.

The publicly owned fields at Tusculum have not been mowed, as far as I know, though there as well ongoing communication is required, as is re-evaluation year to year in order to find the optimum timing and frequency for mowing.

When Lightning Makes Glass

Who burned this bench? Vandalism, maybe,

but what are these three holes next to the bench, that look like they're coated with candle wax?

And this little glass-like figure that resembles a snail?

I wouldn't have seen any of these curious sights if I hadn't started up a conversation about plants with a man walking the nature trail loop near the Harrison Street crossing of the canal. He said go to mile marker 10, between Washington Road and Alexander, and see what lightning did when it touched the ground.

Across from the mile marker was the charred park bench, a dead tree, and three holes in the ground.

And still littering the ground were pieces of glass, or more accurately, fulgurite, created by the intense heat delivered by the lightning as it struck the ground. Pieces of distorted metal cable also were lying on the ground.

The man who pointed me towards the scene, Mark Grinbaum, later looked back at some photos he had taken, dated July 4. Evidently, the strike took place the evening of July 2, when a violent storm came through town, stealing the show from the fireworks display that played to sparse crowds later that evening.

Princeton's New Neuroscience Building Has Thoughtful Native Plantings

Princeton University has been integrating raingardens into the landscaping around their new buildings. The chemistry building has two very large ones on the west side, and the recently opened Princeton Neuroscience Institute building has one that's fed by runoff from the road and densely planted with native species, such as the cardinal flower in the foreground.

The flowering of other species there is more subtle but attractively massed, and just possibly eye-catching enough to attract the momentary attention of car drivers passing by on their way to a university lacrosse or soccer game.

A curbcut allows runoff from the road to flow into the raingarden. This way, the water has a chance to percolate into the groundwater, with any pollution being filtered out in the process. This method of integrating raingardens into developments first came to prominence in Maryland as part of an effort to reduce the amount of polluted runoff flowing into Chesapeake Bay. Back in the 1990s, when I first got interested in raingardens, Prince George's County was frequently cited as the source of manuals for installing these sorts of BMPs (Best Management Practices) in other states.

On higher ground closer to the building, they've planted partridge pea and little bluestem grass, to achieve more of a prairie look.

Some areas are dominated by foxtail grass, which is fun to photograph but likely not the intended vegetation.

In the last photo, below, foxtail finds reflection in the building's windows.

Capturing a Backyard in a Bouquet

A wildflower bouquet offers a summary of a backyard. On the left are the white of boneset with some bright yellow of cup plant peeking out. On the right are mistflower with the deeper purple of ironweed above. Some black-eyed susans (a bred variety) appear orange.

An Inchworm That Wears Camouflage

After a visit to the Community Park Elementary's native garden with some YMCA summer camp kids a couple weeks ago, I sat down to lunch and noticed what looked like a flake of sawdust on my arm. I was about to brush it off when it seemed to move.

Even after a closer look, it still appeared to be a small woodchip that just happened to be able to move on its own volition. A little research showed it to be a camouflaged looper--a kind of inchworm that glues bits of camouflage on its back.

Below is a video that shows it in action.

The camouflaged looper is one of the few invertebrates that creates its own disguise, and can reportedly change the disguise to match whatever vegetation it's on at any given time.

Here's one of the many other posts that can be found about the insect on the internet. The inchworm turns into a Wavy Lined Emerald moth.

Princeton's Underground Brook--Exposed!

There she flow! Ain't she a beaut? Harry's Brook, in all her glory. Where has she been all these years? Why, just beneath the ground, buried alive, embraced by concrete, seven feet wide, seven feet high--spacious compared to most pipes, I suppose, with all the room in the (under)world.

No squeaky wheel, this brook, silent and forgotten while it flows from its beginnings in Palmer Square down past Spring Street and the rest of eastern Princeton towards Carnegie Lake.

Even when it "daylights", which is to say emerges from its underground concrete bondage, at the intersection of Harrison Street and Hamilton Avenue, most people don't notice.

This wasn't always the case. Back when kids had free-range, be-back-for-dinner childhoods, some used to spend part of their summers spelunking, which is to say exploring this manmade underworld, from Harrison Street almost up to Madison Street before the pipe got too small. Must have been nicely air conditioned on a hot summer's day.

On this map, from p. 55 of Princeton's  Environmental Resource Inventory, the Harry's Brook watershed is in off-white. Carnegie Lake is on the right, with a blue line extending towards that black box that used to be the borough's boundaries. The blue line ends abruptly at the "t" in Princeton, which is Harrison Street. From there leftwards on the map to the purple point at Palmer Square, Harry's Brook is underground. When heavy rains fill its concrete corridor to the brim, the brook spills out onto the streets, which can be thought of as ephemeral tributaries of the brook. The streets we drive on are connected by pipes directly to the brook, and are therefore part of it. If the streets are dirty, the brook is dirty.

This photo is at the same location as the first photo, prior to excavation, with two parallel orange lines marking where the brook flows through a clearcut lot on Linden Lane just up from Hamilton Avenue.

A friend sent these photos of the excavation for the basement, looking from the opposite side, with the concrete chamber for the brook exposed there on the left.

In this view of streets from above, the colored line is the creek, which flows underground through the backyards of houses on the south side of Hamilton Avenue.

Before it was put underground, Harry's Brook upstream of Madison Street was made to conform to the grid of downtown Princeton, as seen in this map from 1906.