Thursday, March 23, 2023

Princeton Environmental Film Festival

The Princeton Environmental Film Festival begins this Friday, March 24. Check out the schedule.

One movie with local connections is Dark Sacred Sky, featuring Princeton University astrophysicist Gaspar Bakos, an advocate for reducing the waste light that has deprived us of the beauty and fascination of the night sky. Gaspar has been helping us prepare a telescope for use at Herrontown Woods.

According to the website, 

"Dark Sacred Night" is a special storytelling project of the Princeton University Office of Sustainability. The screening will be followed by a Q&A with filmmaker Jared Flescher and Bakos."

Friday, March 03, 2023

May's Cafe and a Nature Hike--This Sunday in Herrontown Woods

This Sunday, March 5, I'll lead a late-winter nature and history walk at Herrontown Woods.  

Meet at the main parking lot off Snowden Lane at 11am. 

Come early to get coffee, homemade treats, and conversation at our pop-up May's Cafe at the Barden from 9-11. 

There are a few signs of spring. The snowdrops are in full bloom at Veblen House. At least one of the black vultures has returned to the corncrib near the Veblen Cottage, where it and its mate have raised their young in past years. And we have an interesting sustainability project going on: milling fallen trees into lumber to use to build a boardwalk.

Considering the Chinese Praying Mantis an Invasive Species

In the past, praying mantises of all sorts were looked upon as beneficial insects that consume insect pests. A few things have changed in this regard. For one, insects in general are becoming fewer. My observations haven't been systematic, but I've noticed a steep decline in pollinators in the past few years, and a coinciding increase in insect predators, particularly Chinese praying mantises. And it's a stretch to believe a predatory insect is going to only consume insects that we consider harmful. Last fall, I found one chowing down on monarch butterflies

In my backyard I recently found four chinese praying mantis egg cases in close proximity. I'm thinking the best thing to do is to destroy them or put them in the trash. One post that helps distinguish between the different species of praying mantises and their eggcases also recommends feeding the nonnative eggcases to chickens. 

Past posts on praying mantises.

Friday, February 17, 2023

A New Environmental Resource Inventory for Princeton Takes Shape

There's a nice writeup on Princeton's Open Space Manager, Cindy Taylor, in TapInto Princeton. She'll be leading a presentation on Wednesday, Feb. 22, about the new edition of the Environmental Resource Inventory (ERI) that she's been working to prepare for Princeton. Among the many others contributing to the update are councilwoman Eve Niedergang and members of the Princeton Environmental Commission (PEC). The PEC will host the presentation, which should get going soon after 7pm. The public is encouraged to tune in and participate.

If you are wondering what an Environmental Resource Inventory is, you can take a look at the current ERI, which I played a considerable role in creating. Starting in 2007, as a member of the PEC, I worked closely with a consultant, Chris Linn, on that previous update of the ERI, the first update since 1978. 

It seemed appropriate that a resource inventory would include plant inventories--long lists of which plants are found where in town. And so the next year, in my role as resource manager for the Friends of Princeton Open Space, I led many walks in various preserves to inventory the plant life. With help from a Princeton University summer intern, Sarah Chambliss, we compiled 22 plant inventories. 

I added many photos, and a section on invasive species, including mention of the emerald ash borer. Though the ash borer had yet to reach NJ in 2010, it has by now already killed most ash trees in our area, just 13 years later. 

To document some environmental history, I'll mention the following. The PEC, chaired by Wendy Kaczerski at the time, paid for the 2010 ERI using borough and township funds and a matching grant from The Association of NJ Environmental Commissions (ANJEC). The study was carried out by the Delaware Valley Regional Planning Commission (DVRPC), with input from the PEC and borough/township staff. 

Chris Linn of the DVRPC did most of the work to compile and write up the ERI. That document has served the town since it was published in January, 2010. Some of the acknowledgements are below. Looking at the names now--among them Rosemary Blair, Grace Sinden, Casey Lambert, Vicki Bergman, Greg O'Neil, Charles Rojer, Wanda Gunning, Gail Ullman, Ted Thomas--brings back good memories and is a reminder of how deep are the roots of environmental advocacy in Princeton. 

Liquid Winters and Time-Bending Blooms

Long time local botanist Betty Horn sent me an email some days back--February 10, to be exact--reporting that she had just found a hepatica blooming in Herrontown Woods. Hepaticas in early February? This was news. 

Without asking, I knew nearly exactly where she had found it. If you're a field botanist, you maintain a mental map of where you've found certain special plants growing, and in Princeton, my mental map has exactly one location for hepaticas, along the ridge in Herrontown Woods. Sure enough, she had found it there, given a head start by the warmth of a nearby boulder and the snowless winter. 

Hearing the news, another botanist friend, Fairfax Hutter, checked out some hepaticas she knows of in Hopewell. No flowers, nor any buds, she reported. Betty looked back at her records and told me that "the usual time for hepaticas to bloom is early to mid March, and sometimes as late as the first week in April." 

Another early flower is snowdrops--a nonnative spring bulb that decorates the grounds around Veblen House. The first bloom I noticed this year, for the record, was on Feb. 6.

Before moving to Princeton in 2003, I lived in Durham, NC for 8 years. Winters there were much like the one we've had here in New Jersey this year. The default was no snow, and if a snowstorm did come, it became a spontaneous holiday, with schools shut down for several days. It could be said that New Jersey is the new North Carolina, with Georgia in hot pursuit, so to speak. 

The shift towards a liquid winter has made for dramatic changes in our "fillable-spillable" minipond in the backyard. It's a 35 gallon tub that captures runoff from the roof, originally conceived as a pond that could be easily emptied when our pet ducks had made it muddy. 

Like an artist who has lost inspiration, it hasn't produced very interesting ice patterns the past few winters, nothing like that stretch from 2018-19, when intermittent freezes and thaws caused it to behave like a canvas for the profound artistry of nature. Each freeze would bring new and endlessly varied patterns in the ice. 

Saturday, February 11, 2023

How Fallen Leaves Can Reduce Flooding

A kindred spirit in Durham, NC, naturalist Riverdave Owen, took the time last fall to count the fallen leaves freshly fallen on one square yard of his land near the Eno River. 

Posting this photo on facebook, he said the count totaled 1600 leaves. "After extrapolating that count, I estimate this year's autumn leaf drop for this entire half acre property to be approximately THREE MILLION LEAVES! Instead of raking, blowing and hauling them away, they are left as food for a myriad of tiny intermediaries who then return the foliage's organic nutrients back to the trees from whence they came .."

As Riverdave points out, the habitat created by leaves certainly is important. Just think of the spectacular increase in surface area they provide when they fall on the ground. Each leaf has surface area on front and back, and as they accumulate they create myriad tiny spaces inbetween. 

An additional benefit of leaves that tends to go unmentioned and unexplored is the impact of leaves on stormwater runoff. If I had the patience to collect data, I would take that square yard of leaves, weigh it when the leaves are dry, then soak the leaves and weigh them when wet. The difference in weight would be the amount of rainwater sequestered by the leaves themselves during a storm. Multiply that by all the square yards covered by leaves in a community, and you'd find out how much water is absorbed by leaves rather than contributing to downstream flooding. 

But leaves do more than absorb rainwater. They also help make the ground beneath them more absorbent. Exposed soil can harden and dry out, making it behave more like impervious concrete when the rains come. If instead the ground is covered by leaves, the leaves' slow decomposition softens the soil with organic matter and promotes soil life whose activity in turn opens up and maintains channels for water to seep into. 

Wednesday, January 25, 2023

Princeton's Nowhere Land Might Have a Future

The municipality of Princeton's newsletter broke the news last week that the town has been awarded a $552,000 Climate Solutions grant to restore 45 acres of forest at Community Park North. Kudos to the town, and to FOPOS, which will help with the project. Now, what sort of forest, you might ask, is so degraded that it requires more than $10,000/acre to restore? I stopped by last week to have a look.

It's appropriate that the sculpture that now graces the entrance to the woods at the back of the Unitarian church parking lot appears to be in mourning. 

Many hikers who head down the trail won't notice anything amiss, but for me, Community Park North woods has the feel of a post-apocalyptic landscape. Walking its trails, you can imagine yourself to be one of the fortunate or unfortunate survivors after civilization has extinguished itself, leaving invasive species to overrun the wreckage. 

For a virtual tour, click on "READ MORE," below.

Monday, January 09, 2023

What Privet is This? Border Privet in Princeton

A botanist friend of mine, John L. Clark, asked one day if I knew which kind of privet we have here in central New Jersey. John's extremely knowledgeable about flora of farflung places like Equador, but he has some charming gaps in knowledge of local flora that I can sometimes help with. Though I knew there were different kinds of privet--European, Chinese, Japanese--I had long been content to just call any thick infestation of the shrub by the general name of privet, and think no further. All the species of privet are nonnative and invasive, so for management purposes, it's not necessary to know one kind from another. 

More important for management is to be able to distinguish the non-native privet from native shrubs with similar appearance, particularly the native blackhaw Viburnum. Both have opposite branching, but privet often has a terminal cluster of small black berries that linger through the winter. And many of the privet leaves linger through winter as well. 

The photo shows the difference in the shape of the buds. The longer bud on the top (curved here, but sometimes straight) is blackhaw Viburnum. The stubby, grayish buds on the twig below are privet. 
Sometimes privet's winter leaves can take on various shades of green, sometimes bordering on purple or brown. 

I was glad John persisted in his quest to find out which privet we have in central NJ. Having lived in the south, he at first assumed we have Chinese privet (Ligustrum sinense), but after posting a closeup of the flower on iNaturalist, he soon learned that we have Ligustrum obtusifolium, latin for border privet.

Posting another closeup, John pointed out various identifying characters of border privet: "Corolla tubular with small lobes (the tube longer than the lobes), Shoots pubescent (i.e., NOT glabrous)"

The Penn State post describes "a gradient of four different species: border (L. obtusifolium), common (L. vulgare), Japanese (L. japonicum), and Chinese (L. sinense)." But John has determined that we only have border privet here, probably because it is the most cold-hardy. When I lived in North Carolina, we had a mix of Japanese and Chinese, with the Japanese having much larger and glossier leaves. 

Thanks to Inge Regan and John Clark for these photos. Winter, by the way, is a great time to go after infestations of privet in the backyard or local woodlands. Come by Herrontown Woods on Sunday mornings after 10:30am and you'll likely see the Invasive Species of the Month Club clearing swaths of privet to make room for native species.

Sunday, January 08, 2023

Rogers Refuge Featured in the Princeton Echo

For the past two years, Princeton Echo has started the new year with a feature article about a local nature preserve. Last year, it was Herrontown Woods, and this year, Rebekah Shroeder wrote an extended portrait of the birding mecca Rogers Refuge and the volunteers who have cared for it since the 1960s. 

The Charles H. Rogers Wildlife Refuge is a hidden gem, a covert part of Princeton's beauty and ecological richness, accessed down an often passed but seldom seen gravel road called West Drive. Climb the observation tower just in from the parking lot and you will see a most unlikely vista for Princeton--a grand marsh.

Since joining the Friends of Rogers Refuge (FORR) nearly 20 years ago, I've gotten to know the many volunteers featured in the Echo article. 

The article draws primarily from an interview with Winnie Spar, an avid birder, poet, and FORR stalwart. 

Charles Rogers and Tom Southerland were the environmental activists who first called for protection for the wetland back in 1968. Tom Poole was another early advocate. Winnie's husband Fred Spar led the group beginning in 2005. Laurie Larson has been a longtime member who created and maintains the website, Lee and Melinda Varian provided critical leadership after Fred Spar passed away, and most recently, David Padulo has taken the helm. 

Important support, particularly for fighting the invasive Phragmitis, has come from the Washington Crossing Audubon and Partners for Fish and Wildlife. Winding through land owned by the American Water Company, the Refuge's trails are kept open by volunteers. The town of Princeton helps out, particularly with maintenance of the pump that augments the water naturally flowing into the marsh from the Institute Woods. The town also funds deer culling that has allowed native habitat to rebound. For my part, I was commissioned back in 2006 to write an Ecological Assessment and Stewardship Plan for the refuge. That assessment includes a detailed plant inventory. Mark Manning and his son recently conducted an inventory of dragonflies and damselflies, and the extraordinary list of bird sightings continues to grow. The article also mentions Betty Horn's work to maintain the University's Rogers Bird Room, and an online exhibit called Capturing Feathers: A Digital Collection of Bird Imagery.

Congratulations to the Friends of Rogers Refuge on getting well-deserved recognition in the Princeton Echo. The article will reportedly also appear in U.S. 1. 

Past blog posts about the Refuge can be found by putting the word "rogers" in the search box of this blog. Some examples:

Friday, January 06, 2023

Conspicuous Earth Hugging By Trees

An endearing feature of trees is their affection for the ground. People hug trees now and then, but trees spend their whole lives hugging the earth. Like humans, trees lust for the sky, but unlike humans they know that quest requires a good foundation, and find ways to hold on tight. Here are some of the more demonstrative embraces seen during a recent visit to Coconut Grove, Florida. All except the first were seen at Fairchild Tropical Botanical Garden.

Root flare is a sign of health in trees, but I'd never seen the likes of this. I'm calling it a kapok tree (Ceiba pentandra) after encountering this charming video that describes its buttressed base and the fluffy seeds that used to provide stuffing for life vests. 
The extravagant buttressing is reminiscent of the fins of a rocket that in this case can reach more than 200 feet tall, vaulting above the rainforest canopy. With seedpods packed with useful fiber, it's not surprising that the kapok is in the same plant family as cotton--the Malvaceae, also known as the mallow family. 

One of Princeton's native members of that family is the rose mallow hibiscus (Hibiscus moscheutos), fairly common along the shores of Lake Carnegie and in raingardens.
The ombu, a native to the Argentine pampas that goes by the latin name Phytolacca dioica, develops a conspicuously bloated base that with time can become convenient for sitting. If you haven't seen one, just imagine a 50 foot high pokeweed--our local Phytolacca americana with very similar leaves, flowers, and berries. 
I was impressed by this tree's buttressing, 
and even more impressed with this larger specimen.

With leaves like that, I was sure it was some sort of yucca, but no. The iNaturalist app called "Seek", my new botanical companion for the trip, called it Pandanus tectorius, a kind of screw pine. With those mangrove-like roots, it's not surprising that screw pines grow along coasts and are wind and salt resistant.

Native mangroves have similar adaptations. Though they have lost a lot of territory, as development has transformed the Florida coast, this one still finds some ground to hold onto.

Had to look at the plant marker for this tree with a bloated base. Surprise! It's the ponytail palm--the same species we have growing in our living room in Princeton. 

Another name for ponytail palm is elephant's foot. 
This tree's swollen base is the boulder that it is growing on.

Back in Princeton, at the Barden in Herrontown Woods, a white pine shows some flare for root flare.

Tuesday, January 03, 2023

Strangler Figs: Airborne Roots and Flying Buttresses

Coconut Grove, FL, where I was fortunate to spend a week with family for the holidays, is named after its palm trees, but the tree that will catch your eye more than any other is the strangler fig. 

How silly we are, these extraordinary trees seem to say, to think that trees should start life on the ground, have only one trunk, make their flowers seen and keep their roots tidily hidden. 

The strangler fig's logic is clever. How can a new tree survive in a tropical forest where existing trees cast deep shade and have a lock on soil nutrients? It starts its life as if on stilts, as an epiphyte high in the canopy, sprouting on the trunk of another tree. Oftentimes, the seeds, freshly digested by a bird, catch in the rough bark of a live oak, or a cabbage palm. Declaring itself improbably independent of nutrition from mother earth, it lives at first on air and rain, growing stems skyward and roots earthwards. When the roots reach the ground, the strangler fig's growth accelerates. The above ground portions turn into multiple trunks that envelope the host tree. That embrace can ultimately prove lethal, providing the strangler fig with a convenient supply of additional nutrients as the host tree rots away. 


More and more roots are sent downward, each one turning into yet another trunk when the roots reach the ground. Surely if one trunk is good, then many must be much better. The result brings to mind a cathedral replete with flying buttresses. 
The result of all this free-thinking, or if not thinking, then free-doing, is a tree you can walk through. 

This old beech tree in the Institute Woods in Princeton achieves a somewhat similar effect, though it's just one trunk that has rotted through. A closer equivalent in our forests is achieved in a more covert fashion. Trees like beech, sassafras, pawpaw, black locust, aspen, and the blackhaw Viburnum sprout new trunks as their roots spread underground, creating what appears to be a grove of trees that is in fact one individual.
Wikipedia lists 13 different species of strangler fig around the world. This one at Barnacle Historic State Park is the native Ficus aurea, whose fruits the sign says are edible. 

I'm guessing that many of the other strangler figs--those with myriad trunks like this impressive specimen at the University of Miami--are banyan trees from India.

On the left in this photo you can see some aerial roots growing towards the ground. 
Here's a closeup of a cluster of soil-seeking roots growing downward from a limb--another tree trunk in the making.

What little bamboo I saw in Coconut Grove paled in comparison to the expansionist aims of strangler figs. 

This fig appears ready to eat the pavement, 
while others drape themselves over walls, 
or probe the local infrastructure.

This strangler fig was so bold as to break into a tiger's cage.

Fortunately, there's no tiger living there now, just a couple of chickens. 

I forgot to mention the hidden flowers, which are borne inside the fruit and accessed only by a tiny wasp. Each species of fig has its own specialized species of fig wasp to fertilize it. For more reading, and some cool photos of just how tiny those wasps are, here's an interesting post. This Forest Service post describes the mutualistic relationship between the wasp and the tree, and says the U.S. has only two species of native fig. 

For anyone headed down Florida way, a good example of a banyan tree can be found at the Marjory Stoneman Douglas Minipark, named after the famed activist and author of The Everglades: River of Grass.  

Monday, December 26, 2022

Names I Remember, Names I Forget

One ongoing self-observation that I've had through a life of nature observation is that there are some plant names that resiliently spring to mind, and others that remain persistently unretrievable no matter how many times I learn and relearn them. For example, the latin names Gleditsia triacanthos and Robinia pseudoacacia look esoteric and intimidating, and yet for some reason I can summon them instantly. They refer to honey locust and black locust, respectfully, though I don't knowingly have any deeper interest in or respect or affection for these two trees than any others. Well, that's not completely true. I love black locust because it resists rot and burns clean. It can lie on the ground for years and still make great firewood. And a thornless version of honey locust makes a wonderful shade tree in public squares, its tiny leaflets melting back into the landscape in the fall. But I love other trees for their traits just as much. Gleditsia and Robinia, then, are two trees among many in my mind, and yet their names remain buoyantly floating above the others, at the top of the heap and the tip of the tongue. 

At the other extreme lies fennel, a delicious, fragrant vegetable that grows gloriously. A friend made a casserole with fennel and leeks wrapped with prosciutto, the cheese on top baked to a golden brown. It was to die for, and yet the word "fennel" still dropped down into the cerebral abyss, dredged back up just now only by once again googling "plant that tastes like licorice." Similarly, there's a kind of lightbulb whose name I can never remember. The others come dependably and quickly to mind: florescent, incandescent, LED, mercury vapor. But the other one ... I think it starts with an "a" but I could be wrong. That's right. I was wrong, again. Had to google. It starts with an "h," as in "halogen." 

What's the difference here? Gleditsia and Robinia make a merry, musical pair, both with impactful accents on the second syllable: gle-DIT-see-a and ro-BIN-ee-a. Fennel and halogen are less musical, with the accent landing heavily on the first syllable, like tunnel, or funnel, or allergen, or estrogen, or pathogen. But "merry" and "musical" also have the accent at the beginning, so maybe it's that the words "fennel" and "halogen" get less merry and musical after the first syllable, with consonants that are soft and easily swallowed up. I often think about this when comparing the names "Veblen" and "Einstein." Einstein has a memorably sonorous name that can be drawn out deliciously when spoken, like a double exclamation point, fitting for his matchless legacy. Veblen, on the other hand, whose quietly extraordinary career flew under most people's radar, then was long left for forgotten, has a name with soft consonants and indistinct vowels that are all too easy to mumble.

There's a belief that forgetting someone's name reflects a negative view of that person, but I find I can just as easily forget the name of someone I have just met and like. Next time that happens I'll pay attention to the sound of the name itself. It's fun to explore these things, and maybe the act of writing this will create an inner web of meaning to catch "fennel" and "halogen" before they once again drop into the abyss. 

Thursday, December 15, 2022

The Invasive Species of the Month Club

Surely it's not an original concept, but it's a great idea nonetheless: an Invasive Species of the Month Club. Nature can be baffling in its complexity, intimidating, and for some, downright off-putting. If you love plants, then you welcome the diversity of species out there to be learned. Monocultures are boring. But if you have little curiosity about nature, then complexity becomes onerous, and simplified landscapes like a front lawn are experienced as reassuring. And then there are those who really like nature and want to help it, but for whom plant names go in one ear and out the other.

The Invasive Species of the Month Club, conceived for Herrontown Woods by FOHW board member Inge Regan, helps people get acquainted with invasive species one at a time. The nonnative plants spreading through local preserves are often the same ones popping up along fence rows in the backyard, so volunteers gain knowledge they can put to use at home. Every Sunday morning we gather to go after one invasive in particular. Some can be pulled out by hand; others require loppers.

In application, the concept becomes more flexible. We may not focus on one invasive for a full month, but at least each week there is a plant to be focused on. 

Burning bush, aka winged euonymus, is easy to identify any time of year by the "wings" on its stems, but even easier in the fall when it turns various shades of red or pink. It's pretty, but because deer don't like it, its proliferation is making the forest less edible for wildlife.

We spent one morning early in December pulling out jetbead, named after its clusters of black berries. In December, it can be the only shrub that still has leaves, so becomes super easy to identify then.

Privet will keep its leaves all winter, so will be a good candidate for focused effort through the winter. The leaves can vary in shade of green, confusing someone new to the shrub, but that's the idea of focusing on one species at a time. Multiple encounters with privet eventually lead to a confidence in identifying it in all its shades of green. 

Privet was the main focus of this past Sunday's Invasive Species of the Month Club. The weather was cold and damp, with rain threatening, but surprisingly it was one of our most satisfying sessions. The little boy in the lime green dinosaur coat was totally into it, and we managed to clear a whole section of the valley of a dense tangle of invasives. There's enough space in the tree canopy to power native wildflowers and shrubs there, once the invasive shrubs and vines have been subdued. That's the goal, but the process of group effort and gaining increasing confidence and familiarity out in nature have their own satisfactions.

Sunday, November 27, 2022

The Blob That Swallowed Our Nature Walk

I'd been watching the weather for Sunday all week. It was almost comic how a big pile of predicted rain sat centered over the exact timeframe for the scheduled nature walk at Herrontown Woods--a mountain of rain rising conspicuously, incongruously, out of a prairie of sunny weather stretching into the distance on either side.

The consistency of the weather prediction, which showed the blob sitting in exactly the same Sunday time slot for five days straight, and which ultimately proved accurate, surely represents a triumph for meteorology.  

Astute readers will note a distinct resemblance between the blob of rain that swallowed our nature walk and the drawing of a boa constrictor that had swallowed an elephant in The Little Prince. 

Finally, we bailed, and rescheduled the walk for a week later.  

Wednesday, November 23, 2022

Nature Walk at Herrontown Woods, Sunday, Nov. 27, 1-3pm

A nature walk is planned for this Thanksgiving weekend, on Sunday, Nov. 27, from 1-3pm. If the weather looks iffy, check the events page of the website for an update. 

We'll meet at the Herrontown Woods parking lot at 600 Snowden Lane, across Snowden from the Smoyer Park entrance. Sturdy shoes are a good idea. Maps at this link.

The photo is of a pokeweed that came late to the fall color party.