Thursday, December 29, 2011

Fire's Ecological Role

Fire is an important and beneficial ecological force. Writers like Stephen Pyne have documented how it was in past centuries an important tool for maintaining meadows and open woodlands even along the east coast. Many native plant species have evolved adaptations to and even dependency on periodic fire. In  past years, living in the midwest and later the piedmont of North Carolina, I was fortunate to participate in controlled burns of some small prairies. One prairie was right in the city of Ann Arbor, Michigan, where they regularly burn native prairie grasses and woodlands in their parks, in a very controlled way, of course. Controlled burns are being done at a few preserves in New Jersey, as described in a previous post about Schiff Nature Preserve 30 miles north of Princeton, and more widespread use would undoubtedly benefit habitat and ecological health.

This storyline is seldom encountered in news reports, which focus on war-like responses to wildfires out west.   A post at another website of mine speaks to the gap in people's knowledge perpetuated by this unbalanced reporting: Rethinking News Coverage of Wildfires.

Saturday, December 17, 2011

Communal Bath for Robins

Flocks of robins have been appreciating the backyard minipond the last couple days, arriving in flocks of 20 or so to splash in the shallow water. Their frenzied head-dipping is reminiscent of the movement of the birds on this toy, and wooden birds are much more cooperative in front of a camera.

While half of the flock is in the water, the other half remains perched in the overhanging branches, to keep a keen eye or two out for any approaching photographers. The old apple tree next to the pond, half of its branches dead, serves this function well. The human inclination is to trim trees up and remove all the dead branches, but the birds make it clear they like lots of perches of varied heights--the better to scope out the ground before dropping in.

Friday, December 16, 2011

Let Them Be Cake?

Back in the early 90's, I had two jobs--taking care of indoor plants at a university, and playing weekends in a wedding band. Sometimes the band would play at large surburban reception hall complexes that serviced multiple wedding receptions simultaneously. During breaks, we'd walk the hallways, ornamented increasingly with plastic plants, and note how wedding parties were trending towards hiring D.J.s instead of bands. Real plants and musicians were steadily being replaced by imitations.

Given that indoor plants, and saxophonists playing Top 40 pop/rock, are seriously displaced from their preferred habitats, their phasing out cannot be compared to the rapid changes in habitat many native species are up against.

Something about this polar bear,

these penguins, and the Santa, encased like museum displays, made me wonder if and when the penguins of the southern seas, and the polar bears of the north, will join Santa in the world of make believe and memory. It wasn't a very sweet thought to mix with all that frosting.

The next day, part of the answer was provided by Stephanie Pfirman of Columbia University in a fascinating talk at Princeton University entitled "Managing Arctic Sea Ice".

The quick answer, for those in a hurry, appears to be that polar bear numbers will be decimated in coming decades, but that a residual population might survive through most of the century in an area just north of Greenland, where computer models suggest summer sea ice will linger. Her talk did not focus on penguins, though she did say that one colony of Emperor penguins at the South Pole has already disappeared, for reasons linked to changing climate. Changes at the South Pole are more subtle thus far than in the Arctic. Here is fuller account of her talk:

She began in an uncharacteristic way for a scientist. Back in 1992, when scientists assumed that the big impacts of climate change were 100 years off, she had a dream in which she was flying over the arctic, and all the ice was gone.

Her dream is looking prescient. It is now believed that most of the summer ice in the Arctic Ocean will be gone by 2035, and with it most of the habitat for polar bears and the ringed seals they feed on. Already, the diminishing summer sea ice has triggered polar bear cannibalism and interbreeding with grizzlies.

They still expect the Arctic Ocean to freeze over in winter, but the ice cover is getting progressively thinner. Ice that was 4 meters thick before is now half that. As ice melts in the summer, deep blue water is exposed, which absorbs solar energy that was before being reflected back out into space by the snow-covered ice. (Much like the difference between having a white roof, or a dark-colored one, on your house.) This radical shift, from reflection to absorption of energy, is causing much more rapid heating of the arctic than, say, is occurring in New Jersey.

The food chain of polar cod, seals and polar bears is being further stressed, surprisingly, by pollution that is carried on trade winds from northern Europe and Asia. As an example, Inuit indians have some of the highest levels of PCBs anywhere, and as temperatures warm, these pollutants become more mobile in the arctic ecosystem. Oil spills, an inevitable result as easier access to the Arctic attracts extractive industries, will pose an additional threat.

There is one small hope, however. Pfirman and others have used modeling to determine that the last vestiges of summer sea ice later this century will be found in an area north of Greenland. Discussions are underway to create a refuge there. In this way, a small portion of polar bears has a chance of surviving after others perish.

Though I felt a flush of sadness at the beginning of her talk, Pfirman described the devastating changes in a matter of fact way. Scientific inquiry can have its satisfactions, even when the subject of study is a human-driven process heading full tilt towards tragedy. People in dead-end jobs can seek new ones, but a polar bear in a dead-end habitat does not have that luxury. Some would say a polar bear is inferior because it cannot adapt, yet we are the one's who most clearly show a refusal to change, even in the face of well-studied consequences. It's the scientist's spirit of inquiry, that capacity to be dispassionate and yet deeply engaged, that we could all use, to get past the paralysis of guilt and denial, and figure out what we can do.

Wednesday, December 14, 2011

A Visit From the Claw

A Visit From The Claw

'Twas the month before Christmas, when all through the town,
The streets were chocked full of great mounds of brown--
Yardwaste and tree limbs, dumped without care,
In hopes that the street crew soon would be there.

The kids, how they wished they could jump in a pile
Of leaves dry and crisp, where they'd linger awhile.
But all dreams were dashed! Their dad called a halt
To such thoughts of venturing near the asphalt.

The streets had become so exceedingly narrow,
That bicyclists mixed with the cars at their peril.
The street drains were clogged, the rains made a river.
I watched this insane spectacle with a shiver.

When just down the way there arose such a clatter.
I sprang to the door to see what was the matter.
From round the next corner at once there appeared
A caravan that was demonstrably weird.

With dump truck and pickup and street crew I saw
A giant contraption with grappling claw
That groaned as it scooped up the leaves in great gobs.
One thing that was clear was they wouldn't lose their jobs.

For no sooner did they the street cleaner make,
Than neighbors dumped even more leaves in their wake.
The mounds they grew higher than ever before.
I guessed that our town had gone nuts at the core.

How could such a state of affairs come to pass?
What sense underlies this self-made morass?
Is decomposition a thing to be purged
From yards prim and proper that so blandly merge?

The leaves, they have value, it's clear, don't you see?
To earthworms and robins and flowers and trees.
Let's make room between the back fenceline and shrubs,
And there place the leaves as good food for the grubs.

Hidden from view they will quietly mellow.
As Jefferson did at beloved Monticello.
To ground they return; no need for more work.
As they flatten and fade, no varmints will lurk.

Let humus and nutrients there feed your soil.
The mulch will kill weeds, and save you some toil.
The leaf-softened ground will soak up the rain
And lessen the floods that now seem to gain.

Or, grind up the leaves as you last mow the grass.
Okay, so it might take just one extra pass.
But saved be our streets from a public display
Of all that in nature is meant to decay.

I know that I'm fighting a dominant force,
That flouts local law as a matter of course.
No bureaucrat dares to deliver a fine,
Risking taxpayer wrath of a virulent kind.

But speak up I must, and speak up I will
As long as the streets continue to fill.
This dumping is wrong. It's an ongoing blight.
To all who love sense: Let's fight the good fight!

Background: Yesterday, a man overheard me talking to a friend at the Arts Council about all the leaves clogging the streets. He came over and said that West Windsor has the same problem, and that their town council had just thrown its hands up in exasperation, for lack of a solution to the annual deluge of leaves. The thought of towns all over New Jersey struggling with the same intractable problem, mixed perhaps with the flush of vitamins from eating swiss chard from the backyard garden, had the unexpected effect of later moving me to verse, which I read yesterday night at the Princeton borough council meeting. When faced with adversity, write a poem. By coincidence, The Claw came by our house as I was writing it. My apologies to Clement Clarke Moore for rerouting his 1822 "A Visit From St. Nicholas" down a very messy street.

Saturday, December 10, 2011

Wednesday, November 30, 2011

Ivy's Deadly Embrace

This picture tells the story of a neighbor's Kentucky Coffee Tree  laid low by English Ivy's long embrace. The smaller trunks are the ivy, which had climbed far up into the canopy of the tree. During the freak snowstorm earlier this fall, the snow clung to all that extra surface area created by the ivy, the extra weight of which toppled the tree. The fallen tree blocked the street for a week.
My backyard, too, is in an uncomfortable embrace of English ivy, in that the vine is invading from the neighbor's yard to the north,
cascading in over the ramparts facing the park to the east,
and creeping over, under and through the fence to the south. If a neighbor's runoff is flowing into my yard, I can change the contour of the ground to direct it away from the house, and consider the problem largely solved. But the flow of ivy in from neighbor's yards cannot be diverted, and instead creates a perennial chore.

The moral of this story? Never plant english ivy anywhere that its potential to spread is not blocked on all sides by lawn, pavement or foundation. Cut english ivy off of any tree you wish to live. Better yet, never plant english ivy, and remove as much as you can from your yard.

One approach to getting rid of it without working too terribly hard can be found at  Other related posts can be found by typing the words english ivy in the search box at the upper left corner of this blog.

A Flock of Robins

If I were organized enough to keep faithful track of when migratory birds pass through, I would write neatly and clearly in that hypothetical journal that on Friday, Nov. 25th, some exact number of robins, let's say 15, visited the backyard, accompanied by a few white-throated sparrows, juncos and chicadees. The robins busied themselves flipping over red oak leaves in search of delectable insects or worms hiding underneath. A robin's orange breast starts making complete sense as camouflage once you see it amongst the similarly colored leaves, as if one were the reflection of the other.

When I lived in the piedmont of North Carolina, there would be one day in the fall when hundreds of robins would descend upon the neighborhood and strip the dogwoods of their ripe, red berries. If we were lucky, we saw a green female scarlet tanager mixed in. I've often wondered how these migrations are fairing since an introduced disease greatly reduced the numbers of flowering dogwoods in the eastern forests, and whether the timing of berry ripening and the birds' arrival is being thrown off by climate change. Nature has adjusted to very gradual changes in the past, but the multiple changes--new species, new temperature regimes--we're throwing at it are by comparison very rapid.

Saturday, November 26, 2011

The Annual Purging of Leaves

One of this blog's "pages" (listed in the right column as Leaves) contains my annual letter to the editor calling for clean streets and backyard composting, and each year the dumping of leaves, dirt, grassclippings, branches and garden trimmings on the pavement becomes more emphatic and non-stop. The power of the pen is overrated.
What does a tidy yard gain the homeowner if the street in front of it is clogged with debris? It's as if we've disowned the public space. Dumping on the streets has become a year-round, essentially unregulated activity.

True, the leaves, etc. eventually end up getting composted outside of town, but collecting leaves is a highly mechanized, gas-gulping process that makes municipal workers unavailable for other tasks.
And leaves the streets strewn with organic debris that then adds a nutrient load to local waterways.
Streets function essentially as ephemeral creeks, connected directly to local streams, so that the dumping of organic matter in the streets is akin to dumping directly into a waterway--an urge society was supposed to have cured itself of decades ago.

There was a time when leaves were appreciated, not only for their rich fertilizer value but for their beauty and the joy a pile of dry, crisp leaves can bring to kids.

Many homeowners have abundant space in back, yet make a point of raking all leaves to the street. Seeking to comprehend, I came up with two new possible reasons this year: 1) the frenetic pace of life has caused people to reject the relatively slow pace of decomposition, and 2) since homeowners often take their cues from neighbors, the highly visible practice of dumping leaves on the streets is more readily imitated than the comparatively hidden practice of piling leaves in a corner of the backyard.

Thanksgiving Article on Chestnuts in NY Times

Last year on Thanksgiving, the New York Times had an oped piece on the surprising role eels played in early Thanksgivings, and in American diets in general. This year, there's a wide-ranging piece on chestnuts, which among other things explains why my store-bought chestnuts didn't keep well in the cupboard. Lacking the fat content that helps preserve nuts like walnuts and peanuts, chestnuts need to be kept refrigerated, the article says. Cooking them after they had sat for a week in the kitchen cupboard, I found that the leathery inner skin had become inseparable from the meat.

Friday, November 25, 2011

Frost and Water on Kale

Water interacts in interesting ways with a backyard kale leaf. Here's frost one recent morning, like a miniature game of pick-up sticks.
Put a curly kale leaf underwater, and it develops glittery metalic highlights, much like a jewelweed leaf.
The waxy underside of curly kale gathers water into droplets.

In the same genre, an oak leaf fringed by frost, reminiscent somehow of a deer antler.

Friday, November 18, 2011

Walking Tour of D&R Canal in Trenton Sunday

The Delaware & Raritan Canal Watch will hold a free walking tour of the D and R Canal feeder in Trenton on Sunday at 10am, Nov. 20. The walk will explore the part of the canal feeder between Cadwalader Park and the junction with the main canal at Old Rose Street. 
      More info at the DR Canal Watch website.

Monday, November 14, 2011

Big Changes Come to a Hidden Valley

 There's a hidden valley in Princeton that everyone drives by but no one sees. Just over this ridge is Washington Rd, with athletic fields beyond. Down to the left is Faculty Road and Carnegie Lake.

Despite being sandwiched between a busy road and Jadwin Gym, the valley's rich soil sustains old oaks, tupelo, beech and ash that reach improbable heights.

This year, big changes have come to this long-hidden valley. Approached from Faculty Road, stacks of boulders and heavy equipment suggest some sort of road construction.

 A pile of stumps looks less than auspicious.

Further up the valley, more boulders, bales of hay, and orange fencing.

Giant trees, some a yard thick, have been cut down. How could this be anything but bad news? But wait, this post is getting depressing, so let's start from the top of the valley and work our way down.

The valley, which is to say the remnant of valley that was never developed as campus, begins at the new bridge over Washington Road. In the distance is the new chemistry building and the football stadium.

Looking downhill from the bridge, a lovely little stream meanders peacefully down the valley.

Starting farther up towards Nassau Street, the stream runs underground through campus, then emerges (or "daylights") from a big pipe just below the bridge.

The water immediately encounters what looks like an olympic luge track, attractively armored with stones.

 Further down, the narrow channel flows through a broad floodplain.

All of this--the pleasing meanders, the floodplain for stormwater to spread out into, the series of riffles and little waterfalls over stones--is manmade.

Why would anyone want to remake a stream? After a hundred or two years of flash floods caused by all the impervious surface on campus, the stream channel had eroded the ground around it, and was threatening to undercut Washington Road (beyond the green fence on the right) if nothing was done.

Here's a portion of the old streambed, broad and ill-defined. More photos of the old streambed can be found in a post one year ago when members of the Princeton Environmental Commission were given a tour of the proposed project.

A group from Rutgers developed the plans. In this photo, you can see the hoses used for pumping water around the section of stream being worked on. The "V" of stones at the left is called a "cross-vein". Water flowing over the rocks converges to scour out a pool just below them. Pools, riffles, and a narrow stream bed to focus flow are all characteristics of a healthy stream.

The stacks of boulders, then, are materials used to direct water in such a way that the streambank will survive the flash flooding coming from the hardened landscape of campus.

Lots of digging is required to form an adequate floodplain to accommodate the massive infusions of water during storms. The disturbed areas will be restocked with native plants, and though they had to take down some large trees, many were spared.

So that gets us back to the downed trees. This section of white ash is 36 inches in diameter. I counted roughly 200 annual rings, which are caused by the alternation of light-colored fast spring growth followed by a darker band of slower growth later in the season. The tree, and others in the valley, standing or cut, could well date back to the Revolutionary War. Visitors to Mount Vernon may remember the giant white ash trees in the circular drive approaching the house.

 About 160 years back, this ash began to grow very slowly, as can be seen from the very narrow rings on the left. Perhaps it was shaded heavily by another tree, which apparently fell 120 years ago when the rings began to spread out again.

It is unsettling that such old trees have been cut down, and all the more remarkable that few even know about it in a town that loves and protects its trees. But there are extenuating circumstances, tradeoffs made, factors that mitigate, at least partially, the loss. Erosion from campus has been undermining some of the majestic trees, and this project is meant to reduce that erosion.

Time will tell if the trees that were saved will survive all the disturbance around them. Tree roots are very sensitive. And the carefully designed channel is not necessarily immune from the powerful erosive forces of repeated floods.

One useful pursuit at this point would be to study the rings of the fallen trees to see what they might tell us of Princeton's past.

I had recommended a pre-construction rescue of rare native plants like horsebalm, but the idea probably got lost in the mix. Not everyone has learned to make a distinction between rare wildflowers that have survived for centuries in a valley, and whatever natives one can buy in pots at a nursery.

I had also encouraged them to remove the Norway Maples (mottled green/yellow in this photo and next) that have invaded the valley, since the invasive maples are competing with the old growth natives, and their dense shade will threaten the newly planted natives over time.

Overall, though, there's reason to believe this stream restoration--rare in New Jersey--will validate its good intentions. The project leader spoke excitedly last year during the tour about how he hopes students will find the valley an attractive place to visit, rather than merely serving as a traditional shortcut for athletes heading to practice.

This long-sheltered space, with so many stories to tell of past centuries, is beginning a new chapter worth reading.

Squirrels Take Lead On Sustainability

Squirrels are such showoffs. They're already putting us to shame by harvesting all their food locally, living in zero carbon footprint homes, wearing homemade clothing and making their young walk to school.

Now they seem to be considering using bikes for transportation. There's an essay by a well-known author read long ago--I think of Late Night Thoughts On Listening To Mahler's Ninth, but the author's name, Lewis Thomas, doesn't sound right--that suggests squirrels are the likely successors to humans on earth. Perhaps they're checking out our hardware, assessing our strengths and weaknesses, biding their time.

Note, 2/18/12: I finally came across the essay: "The Fire Apes," by Loren Eisley, from 1949.

Friday, November 11, 2011

On 11.11.11, Some Princeton Trees

In honor of 11.11.11--a uniquely unique, highly vertical day--some Princeton trees of note, in no particular order:

The brilliant red maples at Princeton Shopping Center in a photo taken today, with Fothergilla shrubs adding orange in the foreground;

A clock tower looking very one-ish today next to the trees;
A photo my daughter took beneath a red oak in the backyard;
A descendant of the famous Mercer Oak at the Princeton Battlefield;
A 15/16th native chestnut planted at Princeton Battlefield in front of the Clark House;
A hican behind Clark House, showing the change in bark where a pecan/hickory hybrid was grafted to a hickory base.
Another red maple, planted by a couple in honor of their newborn son at Potts Park in the borough, positioned to shade the play equipment in future years;
And in memorium, a photo sent to me by Eric Tazelaar, of the old, old white oak near the driveway to Mountain Lakes House, before it was blown down this year during Hurricane Irene (see Oct. 28 post).