Wednesday, June 12, 2019

A Botanist's Revisiting of Central Park

Enter New York's Central Park across from the Natural History Museum, and you're likely to come upon one of the giant rocks where kids climb. For a parent whose kids have grown, it's a chance to gaze at the changing skyline in the distance (taller, skinnier), and remember back some distance to that parental mixture of worry and delight as a young daughter explored the sometimes precipitous contours of this massive boulder.

For many people, this spot may not offer much beyond rock, water, and skyline softened by an undifferentiated sea of green foliage.

But for a botanist and wild gardener, this place evokes so much more. That tree on the left in the first photo is a serviceberry (Amelanchier) that in early June is loaded with ripe berries. I gorged while the incurious streamed by on their way to rocks and water.

A massing of cup-plants under a sycamore tree brought back memories of where I first encountered this towering native wildflower, growing untended next to a dumpster in the parking lot of Mark Twain's historic house in Hartford, CT.

The sight of royal fern (Osmunda regalis) brings back memories of all the other places I've seen it, whether planted in my yard or growing wild, back in the depths of Herrontown Woods.

This Virginia sweetspire looks very much like the one in my front yard, but with a grander backdrop, and brings back memories of the one time I saw it growing in the wild, along the banks of the Eno River in North Carolina.

These rosemallow hibiscus are offering little in mid-June to catch the untrained eye, but recognizing them without flowers links Central Park to my backyard, the edges of the Millstone River headwaters, and everywhere else I've seen this native hibiscus growing. Familiarity with the plant in all stages also makes it possible to "see" the big, broad flowers that will come in July. For a seasoned wild gardener, that is, a gardener who has been through all the seasons with this or that plant, the present is enriched by the past and future it holds within it.

The community of plants near the climbing rock--native shrubs and wildflowers that thrive with wet ground below and sun above--is what we've propagated into many areas of Princeton, but Central Park adds the framing of the skyline, rock outcroppings and water. To see it there, or in the parks of Chicago during a recent visit, is to bear witness to a recurring community gathering, each member with its quirks. Buttonbush, with its buttons of forming seeds, is in this particular photo. Many others are not shown, like Joe Pye Weed, lizard's tail, cutleaf coneflower, Helenium, New England aster, cardinal flower--their coevolution in the wild here emulated in a park.

So many steps it takes, to raise kids or raise an enriching awareness of plants, which in turn brings meaning and memory to every new step taken.

Saturday, June 01, 2019

A Few Spring Surprises

Watch spring unfold for enough years and it can start to get predictable in a Groundhog Day kind of way. One group of bloomers segues into the next, year after year. There's a theater piece I wrote called Spring Training, that imagines how Spring's trainer, charged with getting Spring in shape for the annual run-through, would react if Spring decided to go rogue and change the order of flowers on a whim. That hasn't happened, far as I know, despite all the changes underfoot and overhead due to our chemical tampering with the atmosphere. Still, this spring has offered a collection of surprises.

A big surprise came a couple mornings ago, when I dared to walk out into the garden and search for strawberries. Disappointment had been a predictable result up to now, as catbirds, slugs, and who knows what else would claim our berry harvests before we could. True, our past care of the garden had not been marked by a consistent diligence and vigilance, and maybe that was the difference this year. We've paid the garden more attention, and in return it provided a yield of incredibly unblemished berries.

Daffodils in late May? That's what you get, it turns out, when you plant them in March, rather than the previous fall. These were planted by volunteers who came to a daffodil planting party at Veblen House.

Also at Veblen House, the pawpaws are leapin'. There's a saying about transplanted shrubs and trees. "The first year they sleep, the second year they creep, and on the third year they leap!" It's been four years since we planted these. Close enough. Periodic attention has had to be paid to protect them until they are beyond the reach of the deer.

That's Friends of Herrontown Woods board member Victoria Floor providing scale.

My friend Steven who has pawpaws in the backyard had to hand pollinate them to get fruit. This wasn't incredibly surprising, though it's always a surprise when something that's supposed to work actually works.

Steven reminded me that years ago I had given him a "live stake" of silky dogwood. It probably looked a lot like this one--a two foot long late-winter cutting that, in this case, was left to sit in a bucket of water until it sprouted leaves on top and roots on the bottom.

He had planted it in his "lower 40", a wet area that receives runoff from the yard and some sun from an opening in the canopy. Since then, it has quietly grown into a shrub more than ten feet high.

A live stake of elderberry performed similarly.

Another surprise came when Architect Kirsten Thoft reminded me recently that I'd given her some plants for her "stormwater planter", which utilizes and filters runoff from the roof before releasing the rest into the yard. This is a good option for downspouts that empty onto pavement. Plants I noticed: Virginia sweetspire, tall meadowrue, and royal fern.

If there's a theme here, it's that plants and nature in general demonstrate an impressive growth force when given a chance, and a little dose of tending through the years. That's a realization that never loses its sense of pleasant surprise.

Thursday, May 23, 2019

Two Snakes Embrace in a Preserved Princeton Farm Field

I recently met with DR Greenway's Cindy Taylor to discuss management of 4.5 acres of farmland preserved by Mercer County. The land is strategically located next to Veblen House and Herrontown Woods, near the corner of Snowden Lane and Herrontown Road. It seemed destined to be added to Herrontown Woods, but was not included in last year's transfer of Herrontown Woods from county to town ownership.

While walking the property we nearly stepped on a couple snakes out mating in their field. From what I've heard and read, there are venemous snakes in northern and southern New Jersey, but not here in the central region. This one, or two, look like something a botanist would call a garter snake. I hope they didn't mind too much our human curiosity.

Up until a couple years ago the land was owned by John Powell, who was manager of the Weller farm before it became Smoyer Park. Each year on his six remaining acres of pasture, John would grow a couple head of cattle, a picturesque reminder of when Jac Weller had a real farm across the road, with bulls that would occasionally escape, prompting a surprised neighbor to call the farm to report that there was a bull in the backyard.

The preserved land includes a small pond that's filled in spring with spring peepers.

The 4.5 preserved acres are as close to a clean slate as we get in Princeton. Do we keep it as pasture with mostly nonnative grasses? Or do we shift it to native prairie grasses and wet meadow wildflowers? Periodic mowing would be needed in either case. Letting it grow up in trees would reduce even further the places where shade-intolerant plant species can grow. Or can it still perform some farm-like function? I showed NOFA-NJ (Northeast Organic Farmers' Association) the site years ago, including the adjacent farmhouse, without success.

Meanwhile, we continue our travel through the 21st century. Ash trees on the neighbor's property succumb to Emerald Ash Borer,

while garter snakes know what to do with a field, even if we do not.

Friday, May 17, 2019

Balance and Imbalance in Nature

Here are two examples of insects eating leaves at Herrontown Woods. One is sustaining balance, while the other threatens the survival of beloved native Viburnums. Why is one insect beneficial, and the other highly destructive? The story begins with the sensitive fern, a beautiful native that graces local wetlands and gardens.

Though we tend to think of ferns as delicate, the sensitive fern is a tough, resilient plant in moist ground, sometimes even showing expansionist tendencies in a garden. The "sensitive" in the name refers primarily to its susceptibility to first frost in the fall.

Typically, the aggressiveness of native plants has been countered through the co-evolution over many millenia of other organisms that can eat them. Any plant that becomes super abundant will in turn provide abundant reward for any organism that develops a capacity to eat it, thereby bringing its population back into balance with other species. That co-evolution takes time, given that plants are brilliant chemists, with many chemical and physical defenses that must be overcome by any would-be consumer.

Since deer generally don't eat sensitive fern and our summers are getting wetter, what might keep it in check?

Recently, while weeding the new botanical garden at Herrontown Woods, I found some young sensitive ferns stripped down to their leaf veins. Sensitive ferns, it turns out, are eaten by several kinds of insects, each attacking a different part of the plant.

The culprit here was a little green caterpillar, most likely a sawfly larva.

Presumably, because I haven't heard of any new, introduced insect ravaging ferns, this insect evolved long ago a capacity to digest and detoxify the sensitive fern's chemical defenses. Any predator that consumes all of its prey will not itself survive, so relationships tend to evolve between predator and prey that are mutually sustaining, and therefore promote balance in nature.

The damage inflicted by the caterpillar is therefore reassuring.

By contrast, the insect damage on this leaf, encountered on the red trail leading up to the Veblen Cottage, was not at all reassuring. It is instead evidence of a radical change coming to Princeton's nature preserves that could largely eliminate several important shrub species from our woodlands and gardens. The leaf is of arrowwood Viburnum, one of three Viburnum species that up to now have contributed flowers, berries, and fall foliage to Herrontown Woods' ecological functionality and beauty.

Their continued presence is now threatened by an introduced species, the Viburnum leaf beetle. Past writings about this invasive beetle on this blog can be found at this link. Arrowwood Viburnum tends to be the first to succumb, followed by mapleleaf Viburnum and blackhaw Viburnum. The insect has the ability to completely skeletonize a shrub. Multiple attacks can ultimately exhaust the plant's reserve energy. I saw a skeletonized Viburnum in Pittsburgh some years ago. Its complete stripping of the plant's foliage was in contrast to a native predator that would tend to do only partial damage, leaving most of the plant alone.

Below, from a Cornell University website, is one potential scenario. It suggests that there will be an initial wave of destruction as the Viburnum leaf beetle eats through all the susceptible Viburnums, after which the insect's population will crash, and become a minor pest from thereon, allowing the susceptible species to grow once again. Even if this were to prove true, the introduced pest represents one more shock to the system.
"The viburnum leaf beetle hit us hard in the Rochester area about 15 years ago. During those first few years in which the beetle population peaked most of the susceptible native species like arrowwood, that were growing in wooded areas, were killed. Some landscape plants succumbed to the defoliation then too.

"At that time I would not have recommend planting a susceptible species like the Cranberry bush viburnum. Now however the populations of the beetles are down significantly and it is safe for us to plant species again like cranberry bush and arrowwood viburnums. They’ll get a little bit of damage but nothing lethal.

"Why did the populations go down? It seems with all the very susceptible native plants that were around initially allowed the populations to reach unnaturally high levels and the beetles moved into landscapes annually. With those food sources gone the populations declined. Also, and maybe more importantly, predator insects, and nematodes that affect the larva in the soil have built up and found the Viburnum leaf beetle as a food source!

Monday, April 29, 2019

Nature Walk in Herrontown Woods, Saturday May 4 with John L Clark

Update #2: Great walk, with showy orchids in full bloom. A writeup is on the website. 

Update: The walk will take place as planned. Predicted rain has not materialized.

The Friends of Herrontown Woods will host a nature walk Saturday, May 4 at 9am, co-led by John L. Clark and myself. John is a botanist specializing in the flora of Ecuador. He was an associate professor of botany at the University of Alabama, but family logistics lured him to Princeton, where he joined the faculty of the Lawrenceville School in a long-titled position, the Aldo Leopold Distinguished Teaching Chair. John's also an avid birder, so feel encouraged to bring your binoculars.

Though we've been installing dozens of stepping stones to traverse muddy patches of trail, please wear appropriate shoes.

Meet at the main parking lot, off of Snowden Avenue, across from Smoyer Park. This link takes you to relevant maps.

Some wildflowers recently seen in Herrontown Woods:

Jack in the Pulpit

Spring Beauty

Mayapple--it's flowers are hidden beneath the leaves.

A profusion of skunk cabbage along a stream. When I lived in North Carolina, another species that lined streams and greened up early in the spring, painted buckeye, was reportedly used long ago by pilots to navigate before the trees leafed out.

Trout lily, which was blooming earlier in the spring.

A Slime Mold Imitates an Egg Case

When I saw these lumpy sacks on a tree in Herrontown Woods, I thought some new invasive insect had arrived, and that these sacks would soon burst open, scattering pestilence throughout the woods. That may well happen, sooner rather than later, as a new invasive species, the spotted lanternfly, spreads into New Jersey from Pennsylvania. But an internet search suggests that these unusual growths are not the work of an insect or a fungus, but instead are the work of a slime mold.

Now, slime molds are not something I've spent much time thinking about in life. Somehow, they seldom come up in everyday conversation. But after a brief google search, I'm considering devoting a future life to the study of them. It might even be fun to be one. Apparently, they are single-celled organisms that can live on their own, but sometimes get together and behave in coordinated ways that suggest a collective intelligence. There are some echoes of humanity there.

Wikipedia puts it this way:
"Slime mold or slime mould is an informal name given to several kinds of unrelated eukaryotic organisms that can live freely as single cells, but can aggregate together to form multicellular reproductive structures."
Here's a promising article with a lovely photo, "Slime Molds Remember, but Do They Learn?", which starts like this:
"Slime molds are among the world’s strangest organisms. Long mistaken for fungi, they are now classed as a type of amoeba. As single-celled organisms, they have neither neurons nor brains. Yet for about a decade, scientists have debated whether slime molds have the capacity to learn about their environments and adjust their behavior accordingly."
The tech world even sees the study of slime mold behavior as having applications for self-driving cars.

Other definitions are less promising. Some mornings, I can relate to this one:
"a simple organism that consists of an acellular mass of creeping gelatinous protoplasm"
There, but for a good cup of coffee, go I.

Wikipedia describes how they can congregate and
"start moving as a single body. In this state they are sensitive to airborne chemicals and can detect food sources. They can readily change the shape and function of parts and may form stalks that produce fruiting bodies, releasing countless spores"
The slime mold spotted on a nearby tree at Herrontown Woods during a walk up to the Veblen Cottage appears to have a name, False Puffball, which is just another way of saying Enteridium lycoperdon.

Sunday, April 28, 2019

Saving Bicentennial Dogwoods at Princeton Battlefield

The big Princeton Battlefield/Sierra Club workday earlier this month didn't include attending to dogwoods along the field's edge, but the care we gave them in previous years to liberate them from porcelainberry and other aggressive vines is still serving them well. Some historical research revealed that they were planted by the Dogwood Garden Club for the country's bicentennial celebration 42 years ago.

Back in 1976, before the deer population exploded and aggressive invasive vines spread across the landscape, it was probably much easier to sustain plantings like this. The planting design was logical enough, with daffodils on the ground in front of the dogwoods, and white pine trees forming a nice evergreen backdrop behind.

But now, the daffodils are obscured by invasive shrubs and brambles, and the dogwoods find themselves growing in a sea of porcelainberry vine on the ground that, if not controlled, will quickly rise into the dogwoods to smother them. Meanwhile, the pine trees that now loom large behind the dogwoods drop big branches during ice storms. It's a one-two-three punch that takes concerted effort to counteract, and the state agency in charge of maintenance tends only to the lawn, with little or no on-the-ground knowledge of plantings that have any complexity beyond trees and turf. Volunteers can sometimes fill the gap. Last year's workday was particularly spirited. We cut vines and competing woody growth away from fifteen dogwoods, so that they could continue to ornament the Battlefield and feed migratory birds in the fall.

But like Mr. Incredible says when interviewed at the beginning of The Incredibles movie, the world refuses to stay saved. Already, the porcelainberry is sending new shoots up into the dogwoods, and until some animal or disease comes along to limit the vine's rampant growth, people will need to intervene to sustain some sort of balance that allows the dogwoods to grow.

Meanwhile, out in the fields, delays in mowing have made it possible for the cuckoo flower (Cardamine pratensis) to bloom.

Monday, April 22, 2019

On Earthday, 2019, A Dream

This sermonette describing a dream of sustainability was delivered towards the end of our Climate Cabaret show at Fahs Theater in Princeton back on January 18, hosted by the Unitarian Universalist Congregation of Princeton. The performance was on the weekend before MLK Day, and takes inspiration from Martin Luther King's dream. The text is below, but the video can be found at minute 1:19:40 at this link.


Now, briefly, a dream. We should spend more time dreaming, and this is mine.

We celebrate this weekend the life and work of Martin Luther King, Jr, and so it is appropriate to articulate a dream. It's always easy to criticize, and, as we've seen tonight, kind of fun. It's harder to dream, because if you express a dream, others will immediately start looking for the flaws in any positive action you suggest taking. They'll say, Oh, we shouldn't do that. We should do this!" But in fact, we have to do it all, and do it now. And implicit in that action is a belief in ourselves and our collective power to do intentional good, rather than the unintentional harm that is built into our daily lives.

In his speech in 1963, King spoke of "the great vaults of opportunity", "the fierce urgency of now." He warned against "the tranquilizing drug of gradualism." He said that blacks were living "on a lonely island of poverty in the midst of a vast ocean of material prosperity," and that "Now is the time to rise ... to the sunlit path."

We live in a time of seeming abundance. But in terms of ethical energy, we too live on a lonely island of poverty, while our world is awash in a vast ocean of solar energy streaming down upon us from the sun. Heeding "the fierce urgency of now" requires that we demand that our culture change, that it work not against our future, but instead help us to liberate ourselves, collectively, from our role as dystopia's lackeys. Imagine harvesting as much energy as we consume. Imagine powering our mobility and comfort while leaving no chemical trace on the planet, but instead merely switching electrons back and forth, like in a digital camera that can collect an endless stream of memories without changing the world around it.

To take action now, not knowing quite how we'll pull it off, is to believe in ourselves, to tap into that great well of resourcefulness and invention within us and our culture, to believe once again in the future.

I will end this sermonette with my favorite words from the song we're about to sing (based on the melody of John Denver's "Country Roads"):

All my travels now are haunted--

Trails of carbon rising up behind me.

All I want is some clean energy

Captured from the sunlight

In my batteries.

There's a road we can take

To the place we belong.

West Virginia, keep your mountains. Let the sun take us home. 

-- S. Hiltner


Sunday, April 21, 2019

Squirrels Mating?

Sitting in bed this morning, I happened to look out the window. New leaves are sprouting on the old silver maple growing at the back of the property. The big knot hole is still there--home one year and maybe others to a screech owl family--something we discovered only when my daughter came across a baby owl in the garden that must have fallen from the nest.

This morning, though, what caught my eye was a tussling of squirrels high up in the canopy. From a distance, there appeared to be two, and they appeared to be mating. It was the most daredevilish style of romance, with a tussle high up, then one squirrel in free fall for ten feet before catching hold and dashing right back up for more. Then both fell, for what looked like twenty feet, miraculously catching their fall on a lower limb and again dashing back up to a higher spot to continue what was either wrestling or mating, or both. Passion and altitude would not seem a good mix, yet the squirrels looked ready to risk all, and in the process demonstrated the depth of their acrobatic brilliance.

Saturday, April 13, 2019

Fig Buttercup Alert--Little Flower, Big Problem

Yes, spring can be lovely, with some cheery displays of daffodils, and magnolia trees in their glory. But it's also an all too good time of year to witness with dismay and alarm the ongoing and accelerating invasion of the Princeton area by fig buttercup. Also known as lesser celandine, it's a small spring ephemeral that seduces with its pretty flower, then takes over your yard and garden.

It has already radically changed the spring landscape over in the Pettoranello Gardens and Mountain Avenue area, and I've watched it spreading from yard to yard over the past five years in my neighborhood near Hamilton Ave and Harrison Street.

These photos are from Maple Street just down from Nassau Street, where a still localized infestation is radiating out from one of the yards. A yard will have one or two plants the first year, dozens the next, quickly multiplying to hundreds and thousands. It's pretty easy to see whose yard was first by the density and extent of the invasion.

Across the street, the fig buttercup is taking over the lawn and flower beds.

The next door neighbor has an invasion in its earlier stages.

Why be concerned? There are many degrees and styles of invasiveness. I'll compare fig buttercup with other aggressive plants below, but here are the essentials: Fig buttercup is an introduced species that has escaped any limiting factors that may have been present where it evolved. It's poisonous, so nothing eats it. The seeds and the abundant underground tubers allow it to spread rapidly. It can grow in the sun or shade, garden or nature preserve.

Some gardeners may feel relief that, like other spring ephemerals, it will fade back into the ground after a couple months. But that seems small consolation as it increasingly displaces other plants that might otherwise grow.

By comparison, myrtle is a groundcover that people plant and may later regret as it takes over flower beds. But it doesn't spread down the street to ultimately pave the local watershed. It merely vexes the gardener who planted it.

By the same token, wisteria vine poses a much smaller threat than porcelainberry. Though an abandoned wisteria vine can spread over an acre or more, weakening trees and suppressing all other growth, it doesn't spread by seed, so remains localized. Porcelainberry is a vine that not only smothers all other vegetation, including trees, but also spreads to new locales by seed.

Most pesky weeds of the lawn--wild garlic, dandelion, false strawberry, ground ivy, etc--have not become problems in nature preserves because they are either edible to wildlife or intolerant of shade.

That's what makes invasives like fig buttercup and stiltgrass stand out as major threats. They spread rapidly, tolerate shade and a variety of soils, and nothing eats them. Since fig buttercup dominates in spring, and stiltgrass dominates in summer and fall, they represent a one-two punch that dominates the landscape visually, and leaves little chance for other herbaceous species to prosper. Since both are not eaten, yards and preserves become increasingly inedible for wildlife.

Fig buttercup can be confused with winter aconite, which also blooms early with a similar flower, but the leaves are much different. Though nonnative, I've never seen winter aconite spread beyond the limits of a yard.

This photo shows the native marsh marigold in the foreground, with leaves much larger than fig buttercup's, which is in the background. (For a closeup comparison of the two species, click on this link.) The marsh marigold, by the way, is very rare. I've seen it only a couple times in the wild. I planted the one in the photo, over at Pettoranello Gardens, purchased from Pinelands Nursery many years ago.

Click here for past posts about fig buttercup (lesser celandine), including a letter I wrote to the Town Topics two years ago that struck a nerve.

What to do? If there are just a few plants, you can dig them up and put them in the trash (not the compost), being careful not to leave any small underground tubers behind. But though I've had organic sympathies all my life, and don't like to use herbicides, the easiest way is to use a squirt of 2% glyphosate on the leaves (Roundup is the most common brand, but more generic forms are available), or else some herbicide more specific to broadleaf plants. We take medicines, and when used responsibly in a targeted manner, herbicide can play a similar role in nature.

Environmentalism has been too caught up in good vs. bad, when the biggest threat to nature and ultimately ourselves, whether it be carbon dioxide or a pretty little flower, is too much of a good thing.

Wednesday, April 10, 2019

Ducks Visit the Backyard

A pair of mallards visited our backyard this morning. The male stood in the middle of the lawn while the female strolled down the garden path, presumably in search of a nice pond to call their own. Were they checking out nesting options? If so, I can't imagine they were pleased. The only standing water is the fillable-spillable tub that catches water from the downspout.

The most appealing interpretation of their surprise visit is that one of them might have been born here five years ago, back when through the luck of the draw we ended upt with a pair of mallards among our fine feathered pets in the backyard. Being a male and female, they soon had five ducklings to call their own. As the ducklings grew, the yard seemed to shrink, overfilled as it now was with ducks and chickens. There were times when we'd hear the nasal call of geese flying overhead, or one or another duck would fly in an impressive arc around the boundaries of the yard, and I'd think for sure they would respond to the call of the wild and venture off into the big world beyond our fenceline. But they never did.

The mallard family eventually ended up at a farm outside of town, whose owners were kind enough to take them off our hands. I read that mallards live 5-10 years in the wild. How lovely to think that they might have come back to have a look around at their old haunts.

For some posts about the ducks we had behind our house on busy Harrison Street, type the word "mallard" into the search box for this blog, or follow this link.

Monday, April 08, 2019

Maintaining a Towpath, and a Meadow

Visiting the towpath for the first time in a long time last week, I found a fresh layer of crushed stone being laid down. May this renovation live long and prosper, for we found out back in August of 2011 what massive storms can do to a wonderful facility like the towpath. That devastation lingered for many months, for lack of any funds to repair the damage. Now, apparently, there's been an infusion of funding, at least for the towpath and hopefully for the NJ parks department itself.

Most people go to the towpath to get some exercise and fresh air next to the water. I go to check on a little nature trail loop we created just upstream of the Harrison Street bridge. The first post on this blog, back in 2006, documents that first year's "harvest" of wildflowers after the state parks department reduced the amount of mowing it was doing in the meadow between the towpath and Carnegie Lake.

Thirteen years later, I'm still serving as steward of that meadow, marking elderberry shrubs so that the parks crew will avoid them during the annual early spring mowing of the meadow. Otherwise, the elderberries would have to resprout from their roots each year and never get a chance to bloom.

Along with the native wildflowers that bloom there in mid-summer, there are remnants of non-native ornamentals, like this row of forsythia, left over from when the towpath was planted by the university to ornament the entryway into campus.

Spring is also a good time to inventory what else needs to be done when the parks crew comes to mow. Maintenance, seldom given its due, makes all the difference, whether it be a trail, a meadow or a planet.

Thursday, April 04, 2019

Nature Walk Saturday, Daffodil Planting Sunday at Herrontown Woods


Frog eggs in vernal pools, the distant hammerings of pileated woodpeckers, spicebush in flower--these are some of the sights and sounds we'll likely encounter on a nature walk at Herrontown Woods this Saturday, April 6, from 9-11am. The walk will be co-led by Mark Manning and Steve Hiltner. Mark is a highschool teacher in Hopewell who has been walking through Herrontown Woods with his son and documenting the species of frogs and salamanders present. He encourages anyone interested in birds to bring binoculars. Steve is president of Friends of Herrontown Woods and can speak to the plant life and history of the preserve. The walk will end at the Veblen House, with some light refreshments. We'll take one of the drier routes through the preserve, but be prepared in case some portions of trails are wet.

Meet at the main parking lot for Herrontown Woods, across the street and down the hill from the main entrance to Smoyer Park. Maps at this link.


In honor of Elizabeth Veblen, we are recreating the fields of daffodils that graced her Veblen House garden. The photos are from the 1950s.

Bring a bulb planter or shovel if you have them, and good gardening clothes/gloves. We'll also do some general cleanup of the grounds. We'll have a few tools and gloves and a little something to drink and eat.

Meet at the Veblen House, down the gravel driveway at 474 Herrontown Road. (Entrance across the street from 443 Herrontown Rd)

Here's another photo from the 1950s, with Elizabeth Veblen walking the grounds of the cottage. Not surprisingly, the distinctive boulder in the foreground is still there, making this photo very useful for helping recreate the landscape the Veblens enjoyed before they donated their homes and land to the public.

The Green Slime That Ate My Ponds

Not quite in the spring spirit, I was going to write about lawn blotch, but that subject was covered five years ago. Better to launch into something new and (uncomfortably) fresh--

namely, the green slime that has crept across my backyard miniponds over the past six months or so. Gone are the depths of clear water I once pondered. The visual is disturbing, recalling as it does

the images of coral reefs whose brilliant diversity has succumbed to overheating, with algae draping itself over the skeletal remains.

All the more distressing to find algae coating water in a well,

and coloring an ephemeral stream down the slope from the Veblen House.

Is this a new algae, accidentally introduced and proving invasive? Or is there something about the unusually wet weather New Jersey has been having? If this stuff covers over vernal pools, the frogs and salamanders will surely be in trouble.

It would be nice to think that this is merely a temporary aberration that will clear up and not return any time soon. A nutrient imbalance, perhaps.  One source describes how phosphorous can be released from the bottom of a pond if the water runs out of oxygen.

As scientists are wont to say, more research is needed, and please leave a comment or send an email if you've been similarly surprised this spring by similar smotherings.

Saturday, March 23, 2019

Prescribed Burns Scent Princeton's Air

This past week, some in Princeton may have detected a feint scent of smoke in the air. As reported in Planet Princeton, the smoke came not from a distant burning house but from the intentional use of fire in habitats at Fort Dix, a half hour south. So-called "prescribed burns" are used to reduce fuel loads in fields and forests, making them less prone to intense, destructive wildfires. Equally beneficial is the impact of these intentional fires (I like to call them "mildfires") on the health of habitats. Many species, particularly in the coastal plain south of Princeton, are adapted to periodic fire that would have occurred in the past, particularly in pre-colonial times when American Indians used fire to manage the landscape. The lack of fire, like the lack of keystone predators, contributes to the unnatural state of our seemingly "natural" areas, and underscores the need for management to better restore healthy ecological functioning in our open spaces.

For some, the idea of intentionally lighting fires runs contrary to environmental goals, since fire releases pollutants and more CO2 into the air, leaves ash on the ground that could be washed into streams during the next rain, and violates the still prevalent notion that we should just stand back and let nature do its thing. On the other hand, periodically burning off accumulated fuels reduces the chance of a much larger conflagration, and the ash can stimulate vigorous new growth that will absorb more CO2 from the air.

The NJ State Forest Service posted information on its prescribed burning, including news of a law passed last year to better promote prescribed burning in NJ.
"Last summer Governor Phil Murphy signed into law “The Prescribed Burn Act,” which preserved landowners’ rights to prescribed burns, strengthened protections for practitioners, and expanded acceptable uses of prescribed fire from reducing traditional hazard fuels to recognizing the benefits of habitat management as well as other forestry and ecological needs."
Back when I lived in Ann Arbor, MI, I helped conduct prescribed burns in prairie habitats in and outside of town. There'd be a fire break around the prairie--usually a 10' wide strip of mowed grass--to reduce the chance of the fire spreading from the intended area. In late winter, a prairie is full of the dead remains of last year's growth. (If you read up on fire ecology, you find out that many species of trees and grasses adapted to fire have evolved to leave behind combustible material that lingers in the landscape to expedite the next fire that comes along. Think of those decay-resistant pine needles, oak leaves, and tall stems of prairie grasses. By contrast, European grasses brought to America tend not to leave much combustible material when they die back in the fall.) We'd begin by having a couple people with drip torches start a strip of fire along the edge of the downwind side. Several of us with garden rakes and broad rubber "flappers" would snuff out any flames headed in the wrong direction. Then, when the fire along the downwind edge of the prairie was going well, the upwind side of the field would be lit on fire. The two fires would burn towards the center of the field. There'd be a dramatic converging of the two fires before they burned themselves out for lack of any more dried grass to burn. It was exciting, efficient, even elegant in the way a field could be cleared of fuel and rendered ready for the new growing season. The layer of ash on the ground looked like the fur of a bison. Freed by the fire from the smothering mulch of last year's growth, new shoots would sprout from the perennial roots, their fresh green a pretty sight against the black of the ash.

The photo above was taken at Schiff Nature Preserve, 30 miles north of Princeton, where they burn their fields and oak woodlands periodically to improve habitat. The state park service does prescribed burns at various places along the DR Canal, though not in Princeton.

It's important to emphasize that prescribed burns require some basic safety precautions, and are only done by professionals after considerable planning.

Are there any habitats in Princeton that could benefit from prescribed burns? One interesting possibility is several detention basins in Princeton's parks that we've converted to native prairie grasses. These acre-sized plantings are surrounded by turf that would serve well as a firebreak.

Similar plantings in a park in Ann Arbor are burned each spring. Families are invited to come to witness the event. First, kids collect seed from the "wet meadows", then everyone steps back to watch last year's stems get consumed by flame. After the fire burns out, the kids scatter the seeds in the ash. Some even bring a picnic lunch to enjoy as part of the event. In the photo, you can see a residential neighborhood in the distance, which is not at all threatened by this elegant horticultural method for managing the lovely grasses and wildflowers that comprise these miniature prairies.