Monday, February 24, 2014

Pollarding in Princeton

Hidden in Princeton's stark winter canopy are subtle signs of a quiet revolution, or at least something decidedly French. Some may view this tree profile as deeply troubling, while others may see a useful approach to solving several problems Princeton and other NJ towns are currently confronting. Halfway down the trees, you'll see a sudden thickening of the trunk. That's where the tree was given a buzz cut, maybe ten years ago. New shoots then sprouted from the cut tips.

This practice is called pollarding, defined as "a pruning system in which the upper branches of a tree are removed, promoting a dense head of foliage and branches."

When I've mentioned this practice to local arborists, the response has typically been negative, with talk of increased risk of disease, and structural weakness.  It's true that I've seen a couple radically pruned trees send out a few feeble shoots the next year, and then die, leaving the likes of a telephone pole in the yard. But results depend on technique, timing, and species of tree. In Europe, where pollarding has for centuries been a clever means of harvesting fuel and forage from trees without cutting them down, the pollarded trees are said to actually live longer than untrimmed trees. (Coppicing, a related practice of periodic heavy pruning once commonly used in agriculture, allows repeated harvest from a tree root that can live for 1000 years.)

My first reaction years ago, seeing a grove of trees getting hacked back in a city park in Madrid, was one of disdain and disgust. How could anyone choose to interfere with a tree's yearning for the sky? There's pleasure in tracing a massive tree's natural ramification, up and up to the top of the canopy. A tree, like a river, should run free.

Though a natural growth form works in most situations, I began to question my dismissive attitude towards pollarding about 15 years ago, when hurricane winds flattened many of the oaks in the NC town where I was living at the time. My view of oaks as being deeply rooted and timeless also came crashing down that day. Though most of the giant trees displayed an uncanny knack for missing cars and houses on the way down, I was made suddenly aware that we essentially accommodate wild trees in our midst, reaping all the benefits and potential downsides thereof. One of the willow oaks that survived the hurricane winds unscathed had been pruned years prior, pollard-style, causing the crown to be populated by many narrow, flexible branches, none of which was large enough to damage a house if it broke off. For years I had looked at that tree's altered growth form with dismay, yet there it was after the storm, a healthy survivor continuing to provide shade with minimal threat of doing harm to the house it was shading.

With Hurricane Sandy and other highly destructive storms sweeping through Princeton in recent years, some homeowners are torn between all the benefits trees can bring in the urban landscape, and the potential downsides of having all that weight poised above the roof. Personally, I have our trees looked at periodically to make sure they're healthy, and accept the risk. But if there's a way to manage trees so that one gets the benefits while minimizing the hazard, that could lead more homeowners to keep the trees they have and plant more.

Now, before buds open, is the time to check out what's being done around town. This photo and the closeup that follows shows evidence of trimming back on a tree that beautifully shades the house in the summer.

Perhaps the tree lost some high branches from high winds, or maybe it was an intentional effort to minimize any additional height.

Once one opens up to the idea of manipulating tree growth, a whole new range of possibilities opens up. Fruit trees of course, like this one in an Italian neighbor's backyard, greatly benefit from regular pruning. But a related approaches can be used for trees grown for any purpose, be it firewood, nuts, forage or shade. Pollarding and coppicing (a related practice) are used particularly in permaculture to maximize production in small spaces. If Princeton is serious about growing its food and fuel locally, a more engaged approach to managing trees will be a big component. Interestingly, these practices are also a means of managing lands for biodiversity, by creating more varied habitat.

These periodic prunings can also have benefits for both soil and atmosphere, by increasing soil organic matter and sequestering carbon. To grow roots, a tree utilizes carbon dioxide from the air to manufacture the building blocks of its structure. By growing roots, trees essentially transfer carbon from the air down into the soil. Each time a tree is pruned, a portion of its root system will die back to rebalance the ratio of roots to limbs. The roots that die back provide a legacy of carbon-based organic matter in the soil and channels for rainwater to seep into. New roots then grow as the canopy recovers, sequestering additional atmospheric carbon underground. More on the many benefits of coppicing at this link.

How these practices would fit into Princeton's goals for shade, food and sustainability are worth considering. The blanket condemnation of pollarding found in pruning manuals doesn't fit with examples past and present of its usefulness. If techniques specific to New Jersey's trees can be developed and accepted by arborists, this approach to pruning could add to the ways tree growth can be controlled to better coexist with homes and solar panels, and thereby increase the number of trees in town.

Here are some examples of pollarding in Paris. 

My writeup on another transformative agricultural practice with big consequences for sustainability, the growing of the currently banned crop called hemp, can be found at this link.

Sunday, February 23, 2014

Snowbound Language

As a salve for winter weariness, follow herein the travails of a snowbound family. With unrelenting snow obliterating the features of their once familiar world, they become even more disoriented as snow begins to blanket their language as well. A convenient glossary of terms can be found at the accompanying post entitled "Principitation."


“Isn’t it snice?” asked the snaughter, looking out the window at the latest principitation. “Looks like snizzle to me,” answered her snaddy with a snown. His snack was still snurting from snoveling the sniveway the snay before.

As they gazed out over the snooftops of their beloved snown, the sunlight danced on the snazzeleen snowscape, all snapples and snazeycakes after sneeks and sneeks of snow.

Snay after snay, Snaddy had snoveled the snidewalk so the sneighbors could sneeze through with their stroller. First had come the snuff, which was pretty enough, but soon followed the snizzle, the snain, and the dreaded snice. The snaughters had been snappy not to have snhool, but as the snours turned to snays, and the snays to sneeks, and the snow rose towards the snooftops, they grew sneary of being snowbound.

“I can't snake it any snore!,” said the snife, sneepless after another snight of her snusband’s snoring. She had snuffered the snings and snarrows of outrageous snortune one snight too many. “I’m snorry, Snowcakes," offered the snusband sneepishly.

All power in the sneighborhood had been snost. “Snead as a snoornail,” declared Snaddy when his snellphone finally snied. “Maybe we could snask the sneighbors to call,” said a snaughter. “But we don’t even snow their snames,” answered Snaddy, snooking out at the snarkening sky.

“I better take the snog for a slog before we get any more snow,” said Snaddy, climbing out the second floor window, snog in snand. The snog, too, was losing touch with other sneighborhood snogs, as each snay’s p-mails became buried under new-fallen snow. Snavigating the snarrow, snow-lined snidewalk, the snog sniffed disappointedly, then snarled at a snogger snotting by.

Seeing the sneighbors approaching, Snaddy hastened to cross the sneet, snarrowly snissing being snit by a snar. "Snow down!", he snouted at the sniver. Just the other snay, the snog had snarked suddenly at the sneighbors, snaring the snickens out of the sniny snot in the stroller.

The trees had long since become snees, and snice had turned many a weak-trunked snee into a snoodle. “Once a snoodle, always a snoodle,” worried Snaddy, snooking at a birch snee arched completely over in front of a snouse. Dodging the snool snipping from the snees, Snaddy wondered how he had ever become the designated snog-slogger.

Finally they returned snome, the snog’s fur filthy from the snirty snow lining the sneets. That evening, as they snat down to sneat some leftover snoup, sneary beyond snords, Snaddy wondered if he’d ever snortle again.

“Is it possible to be blinded by the snight if it’s snight-time?” asked one snaughter, confused by the new snowbound language. “Why are we snalking like this?” asked the other. “I don’t snow,” answered Snaddy, “but it has something to do with snimate snange. Just snink good snoughts, and snope it snoon will be snover.”


Repeated snowstorms this winter, while burying us in their beauty, have laid bare the English language's paltry vocabulary for describing winter's crystalline creativity. "Wintry mix" only goes so far. Nor will importing Eskimo terms like aqilokoq and piegnartoq rescue us from this deficit. We need words that grow out of our own cultural soil, locally coined--words we can use to heap praise or hurl insult, as we gaze in wonder at the opulent beauty of it all, or curse the foot of snow covering the sidewalk.

To fill the linguistic void, I offer the following illustrated glossary, primarily developed during the winter of 2011, when the atmosphere's wizardry was on full display. Study these terms carefully, and you will be better prepared for the next time the heavens let loose with some snowlike substance. An accompanying post, entitled Snowbound Language, uses these terms to tell a precautionary tale of what can happen when snow begins to blanket not only the physical world but our language as well.


Principitation: All the different forms of precipitation that fall on Princeton, NJ. Largely indistinguishable from precipitation that falls anywhere else, but made special nonetheless simply by falling in the 08540 area code.

Snirt: blackened snow lining streets

Snapples: tree limbs broken off by the weight of the snow

Snapples and snirt lingering after a thaw.

Snight: light reflecting off of snow. Also, a snow-covered night

We-cicles: A family of i-cicles

Snoodle: A weak-trunked tree that bends over under the weight of snow and/or ice.

Snouse: A snow-covered house.

As in: "The trees had long since become snees, and snain had turned many a weak-trunked snee into a snoodle. “Once a snoodle, always a snoodle,” worried Snaddy, looking at a birch snee arched completely over in front of a snouse."

Snuff: Fluffy snow.

Kerfluffle: The falling of fluffy snow onto your head when you bump into a snow-covered branch.

Snubbins: snow that falls in the form of tiny beads

Snidewalk: A narrow channel carved through deep snow to allow passage. Also called a sneezeway, because one has to squeeze through it, often while sneezing.

Snazeycake: Snow glazed with a topping of freezing rain.

Other useful terms:

Snain: very wet snow

Snice: icey snow

Snizzle: freezing drizzle

Snool: snowmelt dripping from trees

Snibble: A diplomatic term for any snow of ill-defined category whose name would otherwise be quibbled over.

This vocabulary can easily be expanded by replacing the consonent at the beginning of a word with "sn", to describe that object or action when it is covered with snow. A snow-covered dog, daughter, day or chortle become, respectively, or disrespectfully, a snog, snaughter, snay and snortle. For practice, try applying this rule to "tiny tot". Additional examples can be found in the accompanying short story, Snowbound Language

Saturday, February 08, 2014

Where Vines Tackle Trees

Perhaps we'd suffer cold more gladly if occasionally reminded of how a warmer climate can power unwanted invasions. Our cold NJ winter may, for instance, be knocking back the pine bark beetles that have been moving north into the Pinelands as the climate warms. And we can be thankful that Asian wisteria is not as aggressive here as it is further south. There's a place I used to live, in Durham, North Carolina, where the wisteria grows so densely you needn't touch the ground when you walk. The lateral shoots make a web on the ground,

while the vines reach up and rob the trees of sunlight.

Whole trees collapse, weakened by the weight and lack of sun. The wisteria, which probably started as one small plant brought home from the nursery long ago by a neighbor, has over the intervening decades invaded several acres of woodland that the homes back onto.

Now a 17 acre nature preserve, the woodland displays an exaggerated version of the classic eastern woodland profile--native trees with a mostly exotic understory. Most of the non-native invasives can also be found in NJ, but behave less aggressively because of the cooler climate. Here's a very robust climbing Euonymus, whose hairy stem rivals that of poison ivy.

This tree's branches are actually the lateral shoots of the Euonymus vine.

Elsewhere in the preserve are extensive swaths of Vinca major, English ivy, bamboo and privet, growing so densely that native understory species have little chance of surviving. The preserve was free of Japanese stiltgrass until its seeds hitchhiked in on the tire treads of vehicles brought in to do emergency repair on a sewer.

My friend Perry has been leading workdays to remove the thick stands of privet in this floodplain woods. On the left is before, on the right is after. Invasives removal creates pleasing vistas, safer trails, and sometimes leads to the discovery of a few solitary native shrubs that have been hanging on despite all the competition, such as hazelnut and blackhaw Viburnum.

Thursday, February 06, 2014

Herrontown Wood in Deep Snow

The parking lot at Herrontown Wood was filled to the brim Tuesday, with snow. The combination of thick, wet snow and no wind made for beauteous effects.

Evergreens like Norway spruce were particularly good at catching and holding,

though the few remaining white pines paid a price.

Some deciduous trees that hold their leaves through winter, like American beech, got into the act,

looking well tressed,

along with the white oaks.

A giant tulip poplar went two-tone

while another looked to be the victim of a cream pie prank.

Some of the shrubs took on a jazzy mobile look.

Even the lateral branches of poison ivy (note the hairy main stem climbing up the side of the tree)

and the old fence demarcating the Veblen House property took on an ornamental look.

The moss-covered cliff was nicely framed from below,

and from above. What a great birdwatching spot it looks to be.

Today's catch, a robin.

Wednesday, February 05, 2014

Upcoming Events: Films and Lecture

Despite Princeton's ongoing "Winter in Residence" outdoor programming, which has thus far provided four straight days of skating on Carnegie Lake, followed by extended explorations of different consistencies of snow and sleet, it looks like the Princeton Environmental Film Festival will continue today, Wednesday, with a free showing of "Slow Food Story" at the Garden Theater at 6pm. Urban farming is explored in Thursday's showing of "Growing Cities", Thursday Feb. 6 at the library at 4pm.

Thursday evening presents a quandary, with a 7pm showing of Musicwood at the library, and a 6:30 talk by the author of Roadside Geology of New Jersey, at DR Greenway's Johnson Education Center.

This Friday, Feb. 7, the film festival continues with a couple intriguing films during the day. At noon, there's "Bringing it Home", about the many uses of industrial hemp and the prospects for it becoming legal once again in the U.S. At 4pm, "Tiny: A Story About Living Small" could provide insights into how Princeton could diversify its housing.

Sunday, February 02, 2014

When Carnegie Ice Melted Memories

Two days ago, I stepped out onto the ice on Carnegie Lake just in time to catch the sunset over the Washington Road bridge. Jets, like metal blades on ice, had left their etchings in the sky, to catch the sun's last rays. I skated towards the sunset, unaware of the inner journey about to be taken.

The white flag at Harrison Street had been signaling for three days that it's time to surrender to your long dormant desire to ice skate. 

Princeton's response to winter's call was etched in the light dusting of snow. This is sustainable skating, the sort that doesn't require digging up ancient fuel to run the machines to make the ice or to erect and maintain a building around a rink.

A Carnegie Lake frozen thick, shore to shore, is the work of nature's refrigerator, for which we have so much to be grateful, despite the discomfort of the cold. There are the glaciers that act like slow faucets in summer, feeding rivers that quench the thirst of millions of people and all other life. There are the giant ice sheets perched on the bedrock of Greenland and Antarctica, parking water that would otherwise flood out our coastal towns and cities. And there's the floating ice so important to polar bears and penguins at their respective ends of the earth.

In low light, my camera painted a father and son clearing a new rectangle of ice for a hockey game. Skating makes even the shoveling of snow a graceful activity.

Slowly the frozen scene worked on my mind, thawing out memories of a youth spent in Wisconsin next to an extraordinary legacy of the glaciers called Lake Geneva. I had googled my home town the day before, and was reminded that the lake was once called "The Ice Capital of the World" for the ice sailing regattas held there. Einstein, too, gets mention for his visit to Yerkes Observatory, which like Princeton is perched above a lake.

You cannot grow up near a large lake and think nature to be static. On the first freezing nights of late fall, the lake would steam, exhaling summer's remembered warmth into the air. If the night was calm when the surface froze over, we'd find the ice smooth as glass when it became thick enough to skate on. Each year's ice was different. On a few special years, the snow held off while the ice thickened, long enough to make the whole lake ours to skate on. The ice sheet was a dynamic system, composed of shifting plates that would push against each other as the ice expanded, forming seams. The lake would emit thunderous booms as build-ups of pressure caused these plates to shift. On Lake Carnegie, the seams are an inch wide, but on Lake Geneva they could be ten or fifteen feet wide--jumbles of ice that looked like frozen rivers running through the ice sheet. One year, the forces of expansion were so strong that the ice sheet acted like a bulldozer, creating a berm of broken chunks of ice all along the shore, eight feet high and twenty feet wide.

The best ice was dark and deep, yet clear enough to let the eye trace bubbles trapped far down in its structure. We'd play pickup hockey with all ages mixed together, no referees, and the only spectators were those who couldn't be coaxed to join in. When I was old enough to skate but too young to keep up, a Canadian doing graduate work at the observatory offered wise counsel. Hover near the goal, ready to catch a rebound and shoot it through. Errant passes would require a pause in the game, as one of us scrambled after the puck skidding far off across the lake on the slick ice. I didn't encounter a manmade rink ringed with boards and glass until years later when we moved to a city one state to the east.

Years after that, teaching outdoor education during a deep New Hampshire winter at Camp Union, we were skating at night on similarly smooth, limitless ice when I saw my first and only UFO. Amidst the dazzling array of stars overhead, I happened to look towards one horizon, some distance above the ridge of trees, and saw what seemed like a bright planet where one hadn't been before. It remained steady in glow for a minute, then, maintaining its position in the sky, it curiously faded into nothing, as if rocketing directly away from our planet at unfathomable speed. That, along with other mysteries, hovers along the perimeter of consciousness like stars populating the night sky.

As Carnegie Lake's ice thawed out these memories, my body too was slowly recalling how to skate. There was an initial awkwardness, short strides and cautious turns, but perhaps a half hour in, as the sunset faded to gray, muscle memory kicked in. Knees bent more, strides lengthened, weight began to automatically shift forward or back to fit the motion. Fluid movement returned above frozen water.

At some point, the beauty of that world I once inhabited, glistening expanses of ice beneath radiant skies, began to overwhelm. The skating stopped, and I was overcome by the remembered joy.  After an inward journey back in time, the likes of which had never happened before, my eyes opened to the sight of the Washington Road bridge and a flagged rope stretched across the lake, bearing a sign, "No skating beyond this point". Yes, the sign and I agreed. Best to stop for those upwellings that break through the otherwise solid plane of our day to day existence.

It's hard to say how many people fifty years from now, perched on ice wherever it may be, will have such experiences of recollection. It made me realize how much of our lives is stored in our bodies, and can only be recovered by physically replicating movement. There were more skaters five years ago when Carnegie Lake last froze deep enough to skate on. Maybe the ice was smoother that time, but my guess is that the number of skates in closets has thinned out as the chances to use them become more rare. As the ice grows thin, so will memories.

Several great blue herons flew overhead. Usually, they fly in a straight path, with destination firm in mind, but over the ice they were turning left and right, as if disoriented by frozen circumstance, too young to remember the last time the lake froze over. My daughters resisted going skating yesterday morning--the last chance before warm weather returned--but I insisted, so that they might carry with them some small memory of what it's like to skate on ice stretching so far towards the horizon. It's possible such chances won't come again, but maybe they will. Maybe the jet stream, made slow and saggy by the arctic's melting ice cap, will let more arctic air make extended visits in the future. Global warming brings with it a strong dose of global weirding. What is known is that our skates will stay ready in the basement, and that these last few wintry days have warmed the heart, adding another layer to a rich deposit of memories.

Some links to Carnegie ice from past years: in 20072009, and 2010.