Maria Pinto Speaks on Mushrooms at Labyrinth Bookstore, 2/19

As reported in TapIntoPrinceton, the Labyrinth Bookstore will be hosting a talk about mushrooms by naturalist, forager, and educator Maria Pinto, Thursday, Feb. 19, at 6pm. 

Ms. Pinto's broad interests in cultural and ecological interconnections inform her approach to this fascinating subject. Our Friends of Herrontown Woods is co-sponsoring the event. More info about Ms. Pinto and a colorful description of her debut book is on the Labyrinth website.

If you type "mushroom" into the search box of this blog (top left corner on a computer), you get various posts about mushrooms. 

End of an Era for Skating on Carnegie Lake?

This post in part seeks to correct misinformation widely disseminated about how often skating has been permitted on Carnegie Lake in the past. See further down.

By chance, I was listening in on this week's Princeton town council meeting via Zoom when the subject of ice skating on Carnegie Lake came up. Turned out that town staff had quietly removed Carnegie Lake last year from the list of potential skating sites. Council member Mia Sacks expressed surprise that council hadn't had an opportunity to discuss the decision. 

Staff explained the logic behind discontinuing what had been a long tradition of permitting skating on the lake when the ice reached sufficient thickness. Parking has become limited; staff testing of the ice involves some risk; and emergency services had concerns about the large size of the area between Washington Rd and Harrison Street where skating had traditionally been permitted. Fear of litigation, and fear that social media would draw large, unmanageable crowds, also drove the decision.

Though the concerns had some logic, there was some misinformation put forward in support. Staff knew of only one time after 1996 that skating had been allowed on the lake, but this blog documents five: 2007, 2009, January 2014, February, 2014, and 2015. (Update, 2/16: A sixth occurred in January, 2003.)

One council member claimed people had died from skating on the ice, but offered only the recollections of a relative as evidence. It's very easy to research this sort of thing. The Papers of Princeton website allows word searches of all papers published in Princeton going back to the 19th century. By typing "death" "carnegie lake" into the search box for Papers of Princeton, 78 results come up. Among the 78 I could find no incidents of death from skating on the lake. There was only one incident of death while ice skating, in 1943, when two boys had unfortunately strayed off of Carnegie Lake and skated upstream on the Millstone River. I found five instances of drowning in the lake or canal, unrelated to skating, between 1985 and 1996, and one obituary that told of the deceased's fondness for skating on the lake. If anyone finds documentation that contradicts the above, please contact me.

There was reference at the meeting to a skating injury on Carnegie Lake that had resulted in a lawsuit. The Town Topics reported that the lawsuit dated back to 1996. Skating has been permitted six times in the thirty years since, so it's not clear why the lawsuit would be taking on relevance now.

At the council meeting, four members of the public described how skating on the lake had been a magical experience for them as kids and adults--one of the things that had made living in Princeton special through the years. They pointed to the new parking garage not far from the lake, and asked if the empty Butler tract could be another parking option. One made the argument that during extraordinary cold spells like this, some people will skate on the lake regardless, so it would be safer to provide safe boundaries.

One unspoken cause of the policy change could potentially be the loss of institutional knowledge. The gap between 2015 and the deep cold of 2026 was long enough to weaken a tradition that, like all traditions, is sustained through repetition. Who on staff could remember all the trouble spots to check and mark off on the lake? 

Skating has been permitted this winter at a small pond at Smoyer Park, but it's not the same.

Though it's conceivable that policy will be reassessed, and at least a small part of Carnegie Lake will be opened to skating if and when we get another sufficiently cold spell in the future, what are the chances that the wonderful tradition will ever be fully revived? For those who weren't around to witness past permitted skatings on the lake, here's a taste of the magical experience that would be missed. 

From Winter in Residence, 2007:

The arctic air blew in and Winter, quietly working in its favorite and most deceptively magical medium, transformed a pretty but otherwise cold and unwelcoming lake into a dancefloor, public square and sports arena. Working without a budget or publicity, nor any tools beyond serendipity and physics, Winter drew thousands of local residents to a spontaneous community festival down at Carnegie Lake.

Rows of cars filled the field; skaters of all abilities plied the wondrously smooth ice. One skater propelled himself with a homemade sail. A baby took to the ice in a baby carriage. Along with some pickup hockey games, there was a slippery, slidey game of soccer played slow-motion in boots.

Sweetgum: Embedded Mysteries of a Tree and Its Rare Paneling

A tree can be many things for many people: beautiful or a nuisance, its wood low-grade or its grain profound. A sweetgum tree is all these things for me. This post will give you a tour through sweetgum's beauties and annoyances, including its surprising use as high-end wood paneling in the 1920s and 30s.

First, regard the beauty. What other tree offers such a panoply of colors in the fall? Yellows, reds, purples, orange--sweetgum does it all. True, those powerful colors are only generated by trees that receive adequate sunlight, but there is some wonderful, creative chemistry going on there. Carotenes, xanthophylls, anthocyanins--these are the words that exercise the tongue while stirring curiosity about the possible purpose behind all that color.

There was a time in my life, during my extended undergraduate career, when I acquired a fascination with chemistry, specifically organic chemistry--the chemistry of carbon, the element upon which life is built. While premeds labored through the lectures with high anxiety for the grade they might receive, I was there with a love of subject and a hunger for knowledge.

In decades since, and not talking about premeds here, I've noticed that people who are disconnected from nature tend to be intimidated by nature's complexity. In order to feel comfortable, they surround themselves with a simplified, static nature of mowed lawn and trimmed shrubs. But for those of us who love nature, its complexity is appealing--a richness that rewards endless inquiry and exploration. I remember a bus ride through New England, probably in my 20s, looking out the window and thrilling at the thought of all the chemistry going on in the forested hillsides we were passing by. 

At the same time, it's hard not to be annoyed by the sweetgum's "gum balls" scattered on the ground, prickly and destabilizing underfoot.

Overabundance, too, can turn affection into surfeit. In the piedmont, stretching from central New Jersey down through North Carolina, sweetgum sprouts like a weed in areas we seek to maintain as meadows. Managing remnant piedmont prairies at Penny's Bend in Durham, NC, required mowing or prescribed burns to keep the rampant growth of sweetgum seedlings from smothering rare wildflowers. Grasslands in NJ often require similar intervention.

At least near water, one natural check on sweetgum's rampancy is beavers, who apparently love them for their inner bark laden with sweet gum--the liquid amber found in its latin name, Liquidambar styraciflua. This photo was taken during a walk at Plainsboro Preserve ten years ago. The beavers' preference was so strong, and the sweetgums so numerous, that we saw no other species of tree being chewed upon.

The vexing ubiquity in early succession that I've encountered in the eastern piedmont contrasts strikingly with my experience with sweetgum years prior in Ann Arbor, MI. Being a more southern species, the tree's native range doesn't extend into Michigan, so it's no surprise that a horticultural colleague at the University of Michigan proudly planted a sweetgum as something rare and wonderful, with its fall color and craggy winged stems. 

The sweetgum's wood, too, generates conflicting impressions. It rots quickly if left on the ground, is hard to split, and proves insubstantial as firewood. 

And yet, fifty years ago, my family moved into a beautiful house in Ann Arbor that was paneled in the most appealing way with sweetgum. The wood had a rich, warm glow--clearly a winner for paneling, but I have not knowingly encountered it since.

Then in 2023, we discovered a piece of wood from a packing crate bearing the name Demarest and Co on a wall inside the Veblen House. While researching the Demarest name, I came across an article about American Gumwood. In 1926, the Bureau of the Hardwood Manufacturer's Institute in Memphis, TN was promoting its new booklet: Beautiful American Gumwood: A superb native hardwood for interior woodwork and furniture.  

It took awhile to figure out that they were talking about sweetgum, not another eastern native called black gum. As a friend pointed out, calling sweetgum "gumwood" also risks confusion with the eucalyptus native to Australia, sometimes called gum tree.

The pamphlet begins by describing America's great forests as being our destiny to harvest. I've included long quotes to get a sense of the rhapsodic language.

The story of American gum wood dates back many centuries. Nature requires many years of favorable growth to produce a masterpiece, and in the vast stretches of our southland forests, extending from the Atlantic to the Mississippi valley and beyond, the quiet work of building cell and fibre was going on long before DeSoto and his valiant men first beheld in wonder the mighty "Father of Waters." What a marvel of creation, when from soil, moisture, and sunshine this fine wood came into being, now to be transformed by the hand of man into products that contribute to his well being and enjoyment.

By the mid-1920s, apparently, that enthusiastic harvest had led to more preferred species growing scarce:

Lumbermen have long known gumwood, yet vast tracts have been left standing while other interspersed hardwoods of widely varying species which happened to be wanted at the time, have been cut out. 

Overlooked in the past, sweetgum now stood ripe for the taking.

The tree itself, as it displays its lofty and graceful symmetry, is one of the glories of our native forests. Its sturdy proportions are enhanced by masses of scarlet, orange, and yellow leaves, which change, as the summer wanes. In size, it is heroic; one hundred feet to one hundred fifty feet in height, with a diameter of four or five feet, is not unusual. And some idea of the extent of growth of this important tree may be gained from the fact that with the exception of the oaks, gumwood exceeds all other hardwoods.

If sweetgums could read, they might have felt deeply flattered, but also be wondering if their tombstones were being readied and inscribed. And yet, one cannot be fully dismissive towards tree harvest--we who live in wooden houses and keep ourselves warm through the winter with fossil fuels rather than renewable energy from wood. 

This photo in the pamphlet looks reminiscent of the warm glow of the paneling I experienced fifty years ago, but doesn't capture the complexity and variety of mysteriously generated grains that sweetgum is capable of.

As the pamphlet explains:

Now no wood has more wonderfully interesting patterns than figured gumwood, but it is one of Nature's riddles to account for them. The pattern is not produced in the usual manner by quarter-sawing, although this process will improve any figure if it is already there. All one can say is that some trees have pronounced figured wood, others varying degrees of pattern, and many which show but slight indications of it. Undoubtedly the condition of the soil and the location of the individual tree affect in some mysterious way the structure of the wood. Only when the tree is felled, does the grain show itself as plain or figured. That is what makes the gumwood tree so interesting; it is like finding a }ewel, the value of which depends upon hidden qualities brought out by cutting and polishing.

The quizzled, tangled grain that makes sweetgum hard to split can bedazzle when milled. As with fall leaf color, the sweetgum's grain will vary tree to tree.

The figure ramifies through the wood at random, obeying no known laws. Gumwood logs will each display differing patterns, some subdued, some intricate and ornate.

Go forth, then, dear readers, and if you happen upon a sweetgum along a trail at Herrontown Woods or elsewhere in Princeton, slowly reaching for the dimensions the pamphlet describes, know that you are gazing upon a mystery of creation, whose creative chemistry is not yet fully understood, and whose sometimes plain, sometimes profound grain is impossible to predict from one tree to another.

There's one more passage in the pamphlet that helped me understand why my family home in Ann Arbor was paneled with sweetgum. The 1926 pamphlet may have influenced the couple, Walter and Martha Colby, who built the house in 1933, but they may also have encountered the paneling during their many travels in Europe. The pamphlet explains:

Europe has long recognized the exquisite beauty and texture of American gumwood. In fact, England, France, Italy, Spain, and other countries were first to recognize its fine working qualities. In America, however, its light was for a time hid under a bushel, so far as public acquaintance with its true worth is concerned. But now, due to growing appreciation of its merit, the valuable products of the gumwood tree stand forth proudly as "American gumwood,'* nothing else -so named, and so prized. The old adage, "a prophet is not without honor, save in his own country," no longer applies, if we may adjust this metaphor to a tree.

Here's a career move that musicians know well--a wood that needed to cultivate an audience abroad before it could be valued at home.

The Many Things a Snow Can Do

Skiers must be happy with the snow that looks like it will stick around all week, but even if you don't take to skiing, a snowstorm like the one we just had presents all sorts of opportunities. 

There's the chance for a no-salt collaboration with nature: scrape as much snow as possible off the driveway in the morning, then 

let the sun do the rest. 

While covering some things up, snow makes other things more visible, like the form of this young blackgum tree at the Botanical Art Garden in Herrontown Woods. 

Clinging snow highlights last year's tulip-shaped blooms high up in a tulip tree. 

It makes white pine trees mischievous, sending snowballs my way as a breeze shakes the snow off the top of the tree. Ever get in a snowball fight with a tree? The tree will win every time.

Snow makes a botanical art garden more art than garden, turning trees into sculptures. 

Clinging snow also highlights the shape of a coppiced elderberry bush. Cut down last year because it was too big for its location, it sprouted lots of shoots that can be harvested later this winter to make "live stakes" to plant where we want new elderberry bushes to grow. 

Snow adds frosting to aging rootballs. We left most of the fallen trees in the Botanical Art Garden as art and habitat. Insects need wood for food and lodging. Come to think of it, the drop in insect numbers in recent years may be due in part to a lack of extended snow cover in the winter--cover that in the past insulated them from extremes of temperature. 

Snow is also really good at recycling light in the light-poor winter, and providing clues as to where you're losing heat through your roof. 

It's pretty good for skiing and sledding, too.

Training Deer to Eat MORE Japanese Knotweed

This post represents a first for PrincetonNatureNotes.org, in that it is written by someone other than me. Mark Nowotarski lives in Stamford, CT, and contacted me more than a year ago after discovering a 2014 post I had written entitled Training Deer to Eat Invasives. Independently, he had begun foraging the Japanese knotweed growing in his backyard (young shoots are edible) and noticed that deer began browsing it as well. Released from any co-evolved limits on its growth, Japanese knotweed has spread across the US and globally, displacing native species and overwhelming any human efforts to counter it. Unlike people, deer are 24/7 land managers. Their appetites decide what can and cannot grow in our yards and woodlands. Training deer to eat a relatively edible species like Japanese knotweed could conceivably, in some situations, relieve browsing pressure on the native plant species deer tend to prefer. As the deer in Mark's backyard continued to consume young sprouts of Japanese knotweed, he sent me photos and text that I incorporated into a post a year ago.

This past growing season, Mark expanded his experiments and observations, exploring how a willingness to browse Japanese knotweed could pass from one generation of deer to another. It's still unclear how much of an impact deer browsing could have on the spread of Japanese knotweed, but it's an interesting inquiry. Along the way, we learn about deer family dynamics, the potential grazability of another uber-invasive, porcelainberry, and even the possibility that deer saliva affects the chemistry of plants. Thanks to Mark for sharing his work with us.

Training Deer to Eat MORE Japanese Knotweed

By Mark Nowotarski

In our post last year, “Training Deer to Eat Invasive Plants – Japanese Knotweed”, I shared observations of white tailed deer (Odocoileus virginianus) browsing a patch of Japanese knotweed (Reynoutria japonica) in my backyard in Stamford CT. The local deer had learned to browse the knotweed continuously from spring to fall resulting in drastically stunted canes. This had allowed numerous native plants to recolonize what had previously been an invasive monoculture. Steve and I speculated that perhaps if we cut the fully mature canes in other nearby patches of knotweed (i.e., coppicing), new shoots would grow and the deer local to those patches might browse the new shoots as well. I’m happy to report that that strategy at least partially worked.

Deer Raising Fawns on Knotweed

Before we talk about manual coppicing, let’s talk about how it’s occurring naturally. This first video, shot in May in my backyard, shows you what deer browsing spring knotweed shoots looks like.

A buck with new antlers approaches several knotweed shoots (Fig. 1). He gives a quick sniff, bites the top portions off, and eats them. The cut stems that are left behind are about 2 feet tall.

This particular buck may well be one of the fawns raised on knotweed in my backyard in the prior summer of 2024. Does and fawns form a family group when the fawns are born in late spring. They normally stay together and browse in the doe’s home range for a full year before dispersing shortly before the doe, if she’s pregnant, gives birth to the next year’s fawns. This is how last year’s fawns learn to eat the new shoots of knotweed that sprout in the early spring. The early spring browsing by last year’s fawns coppices the knotweed so that when it sends out new shoots at a convenient two foot height, the new shoots will be available for the new fawns born in late spring.

This year, our doe was, in fact, pregnant and sometime in June, she gave birth to triplets. Triplets are relatively rare (1 in 10 pregnancies) and indicate that the doe is well fed. By July, the doe and the new set of fawns were out browsing the knotweed previously coppiced by last year’s fawns before they dispersed.

In the foreground of Fig. 2 you can also see several native plants growing up through the coppiced knotweed. On the left is Canadian goldenrod (Solidago canadensis). On the right is Northern lady fern (Athyrium angustum) and sensitive fern (Onoclea sensibilis). The deer would occasionally take a nibble of the natives, but they concentrated primarily on the knotweed. 

This suggests that some of the native species less appealing to deer could begin to coexist with browsed stands of knotweed. I plan on trying this strategy next summer and will keep you posted.

I had set up a motion activated trail-cam to monitor how often, and for how long, the doe and fawns browsed the knotweed over the summer. They returned 4-5 times a week and browsed 5-15 minutes for each visit. This lasted from when I set the camera up in July all the way through late October when the knotweed senesced (i.e., dropped leaves and turned brown). So far this winter, the doe and fawns are still stopping by several times a week. In late October an 8-point buck also stopped by in the middle of the night. After a bit of hide-and-seek with the doe in the knotweed, they mated. We can now hopefully look forward to new fawns this spring.

The cycle of fawns being raised on knotweed and then dispersing in the late spring to new territories may be an important mechanism for the spread of knotweed browsing by deer. The question then becomes, can we spread it even further by coppicing canes ourselves.

Expanding Knotweed Browse with Manual Coppicing

At the same time I was monitoring the deer in my backyard I also set out this past year to explore the knotweed stands in our local parks and land trust sites to see if I could find additional evidence of deer browse. About half of the stands I inspected showed signs of early spring browsing. About half of the spring-browsed sites also showed continued summer browsing. Several of the summer-browsed sites showed a significant expansion of the browsed area versus last year. This was evidenced by areas with tall old canes from last year but only shortened canes this year. The deer hadn’t eaten the knotweed last year and it grew to full height. This year, however, they started in the spring and continued through the summer and fall keeping it short.

To try out the manual coppicing experiment, I selected four sites where there was either no early spring browsing or where there was some spring browsing but no rebrowsing of the new shoots emerging from the coppiced canes. Two of the sites did not show any rebrowsing of the coppiced canes. These sites either had no spring browsing or very scattered spring browsing. The knotweed threw out new shoots which grew to full height despite clear evidence (e.g. footprints) of deer wandering by. Apparently, the deer near those stands had not been sufficiently acclimated to knotweed as a source of food.

In the other two sites, however, the deer did resume browsing the new shoots thrown out by the coppiced canes. These sites had heavy spring browsing and well-worn deer trails right next to the knotweed stands.

The next set of figures shows the history of my coppicing experiment at one of the sites where the deer resumed browsing. 

Fig. 3 is a photo taken in April. It shows what an early spring browsed knotweed shoot looks like. It also shows a new shoot emerging from the cane a few weeks after the initial browse.

Unlike my backyard, however, these new shoots were not rebrowsed. By July they had grown to full height. This, along with the well worn deer trail right next to the knotweed stand, made it an ideal location for the coppicing experiment.

The next photo (Fig. 4) shows a section of the knotweed stand where I cut a 6 foot wide by 12 foot long section of the full grown knotweed canes to about 2 feet off of the ground. 

I cut the canes at a bias so that when I inspected them later on, I could tell whether a cut cane was my doing (angle cut) or a deer browse (horizontal cut). Cuttings were placed where they could not resprout or be washed downstream.

A few weeks later I went back to inspect and, much to my delight, the deer were browsing the new shoots emerging from the manually coppiced canes (Fig. 5). 

Where I had cut the canes, the ends were frayed and the canes turned black down to the next joint. Where the deer browsed the canes, however, the ends appeared to be sealed off and even flared out as if from accumulated water pressure coming up through the knotweed. The canes below the deer browse remained green. It makes me wonder if there is something in the deer saliva that causes a deer browse wound to heal quickly. Perhaps knotweed has evolved this way from browsing by sika deer (Cervus nippon) in their home range in Japan.

Once I confirmed rebrowsing of the new knotweed shoots at this particular site, I set up another trail cam to see what sort of deer were coming by. I half expected another family of a doe teaching fawns to eat knotweed.

 

Imagine my surprise when this magnificent 14-point buck showed up (Fig. 6). It wasn’t a family group. It was a bachelor group with up to four bucks coming through at various times.

This buck and several others came by 4-5 times a week to browse not only the knotweed, but the invasive porcelain berry (Ampelopsis glandulosa) growing over the area in the foreground and hanging off of the uncoppiced knotweed canes in the background. In fact, I suspect that the porcelain berry is the primary reason the deer were there. The knotweed was just an additional food source.

The bucks suddenly disappeared in mid-September after they shed their velvet, no doubt to pursue does during the rutting season. I have not seen them since except for one poor fellow with a missing antler. Given how well-worn the deer trail is, however, I expect to see at least some of them again in the early spring.

Deer in a given area learning to eat Japanese knotweed appears to be a multi-year process. It starts with initial occasional browsing of early spring shoots. The spring shoots are then browsed more intensely in the ensuing years. Eventually the deer start browsing the new shoots growing from the spring browsed canes. If the knotweed is in a doe’s home range, then she starts to raise her young on knotweed and then the process spreads as the fawns raised on knotweed go on to establish their own home ranges.

If you try your own coppicing experiments, please let us know how they work out. I’ve joined a project on iNaturalist called “North American Knotweed Ecology Project” where we can share our observations. iNaturalist is a great tool for finding knotweed stands in your area. If you look carefully in the knotweed photos, particularly those taken in April and May, you can often see a deer-browsed shoot here and there. Sites with browsed shoots would be a likely candidates for coppicing experiments.

In the future I hope to learn more about the general phenomenon of deer adjusting their diets to consume invasive plants; how this affects browsing pressure on native plants; and what impact it might have on the deer themselves. The deer won’t solve all of the problems with invasives, but they may very well be an important part of the solutions.

- Mark Nowotarski

Editor's note: A related initiative is the effort to train cattle to eat invasive species. A woman named Kathy Voth appears to be a leader of this approach.