Brood XIV

17-year cicada

Walking into the house after dark, I snap on the light and notice a thumb-sized lump under my shirt, right above my navel. It’s moving, though I don’t feel anything. I lift the shirt and there, clinging to the other side of the green cotton, is a periodical cicada. I pull it off, carry it outside and give it a toss. A dry rattle as it flutters off into the night. Maybe those strange red eyes can see in the dark.

For seventeen years — an eternity for most insects — they’ve been living completely in the dark, the cicadas of Brood XIV. Silent, wingless, and pale as ghosts they have burrowed from root to root, sucking on the milk of trees. Then in late April they began to experience subtle changes in their bodies, growing new muscles, and feeling a sudden strong urge to burrow upwards. Rather than push the dirt behind them like a mole or pass it through their bodies like a worm, their powerful forelegs pushed and compacted the newly thawed earth into half-inch cylinders as they climbed.

They dug to within an inch or less of the surface, making visible mounds in the mud and leaf duff in wetter areas. Skunks and other predators dug some of them up, and for weeks we were puzzled by what turned out to be dried sections of their bore-holes scattered all over our trails. My mother took to collecting these strange artifacts in a shoebox in her study; we couldn’t remember ever seeing anything like it. If we weren’t such rationalists, we might’ve thought the Little People were taking a crash course in pottery.

periodical cicada tubes

The nymphs sat in their burrows and waited for the onset of warm nights, a wait that might have lasted only a couple weeks some years, but this year — THE year, as far as they were concerned — it was closer to six. Four days ago I saw my first red-eyed cicada on a dead raspberry cane and realized that the emergence had begun.

Yesterday — the morning after I carried a cicada in under my shirt — I waded slowly through the thick air of our first heat wave since last April, up to the crest of the ridge above my house and southwest along the trail. It sounded as if our closest neighbor in the valley were operating some kind of machinery, I thought, but couldn’t quite figure out what — an eerie metallic buzz. Then I realized: it’s them. They’re here! I picked my way down to where the slope turned steep, but still the sound was below me, coming from an open area that had been logged about a decade before. The sunny, southeast exposure must have led the cicadas there to emerge earlier than those elsewhere on the mountain.

It occurred to me that there might be some activity on the powerline right-of way. I always associate powerlines with cicadas, in part because their calls have such an electronic quality. But in fact because the powerline opening is several degrees warmer than the surrounding woods, the night before last had indeed been a scene of mass ecdysis there, the nymphs emerging from their burrows, crawling a foot or two up into the vegetation, and climbing right out of the center of their wingless thoraces. By dawn, all would’ve darkened from white to bluish gray with red-veined wings. When I arrived on the scene at mid-morning, nearly every lowbush blueberry and scrub oak shrub was dotted with adult cicadas, and some of them were beginning to take short, clumsy flights, like remote-controlled toy airplanes piloted by inexperienced hands.

I found one two-foot-tall scrub oak as heavily ornamented as a Christmas tree. When I squatted with my camera for a closer look, I noticed the translucent brown larval shells, or exuviae, clinging to the undersides of the leaves. I couldn’t help thinking that whatever whacked-out evangelical preacher first dreamed up that Rapture business must’ve witnessed a 17-year cicada emergence.

cicada exuviae

By this afternoon, I was beginning to hear them from the treetops right outside my door. I walked back up to the powerline to see if I could find any singing at close enough range to film, but they’d all moved on — up into the treetops, I suppose. I also noticed, however, an alarming number of half-inch-diameter holes stippling the ground almost everywhere in the woods — there must be few species of native trees they don’t patronize. The ecological consequences of their aeration of the forest soil must be immense.

Things are going to get pretty loud here in the coming days, I think. As the aforelinked webpage puts it, “Soon after emerging, males begin their constant ‘singing’ while females remain silent. The sound made by adult males is sometimes haunting and eerie.”

After around ten days of cacophony and orgiastic mayhem, the females will begin laying their eggs and the next cycle of this longest-lived of North American insects will begin. Rather than sow their seeds in the earth, as one might expect, they instead plant them in the treetops, long ovipositors slicing like harrow blades into the twigs of trees and shrubs from nearly 80 different species. Each female lays some two dozen eggs per slit, and repeats the process until all her 400-600 eggs are gone. Where two weeks before, the adult cicadas emerged from slits in the backs of their former selves, now they insert their future offspring into slits cut into what will become their nurse-trees.

The true opposite of ecdysis, I suppose, is death, and a month from now the ground should be littered with cicada carcasses. By the time the white, ant-sized cicadas hatch in late August and drop to the ground, most traces of their parents should be gone.

Needless to say, birds, squirrels, and virtually every other macrofaunal inhabitant of the forest will have a heyday, feasting on this almost literal fat of the land. Early European settlers in eastern North America marvelled at the teeming wildlife, almost all of which have by now been sadly diminished, if not persecuted to extinction, with the exception of a few superabundant pest species such as tent caterpillars and white-tailed deer. The mass emergence of the 17-year cicadas is one of the last great spectacles of its kind.

Ending expanded 6/8/08; cross-posted to the Plummer’s Hollow blog. For more on periodical cicadas — much, much more — see the Cicada Mania blog. For an MP3 of the singing, go here. And since I was just talking about nature documentaries yesterday, I’d be remiss if I didn’t mention the fine film “Return of the 17 Year Cicadas” on YouTube.

Stalking the wild lady’s-slipper orchid


It’s hot, it’s humid, I’m cranky, and I don’t feel like writing, so here instead is another thrilling documentary from the Undiscovery Channel. (No, I still don’t own a real video camera, and I’m still using Windows Movie Maker.)

By coincidence, today Bug Girl linked to a CBC exposé, Cruel Camera, and an accompanying chronological guide, Fakery in Wildlife Documentaries. I knew about some of the examples, but others were new to me — for example, that Mutual of Omaha’s Wild Kingdom “use[d] staged confrontations between various species of animals. Perkins was known to also put animals in situations where he will be filmed dramatically capturing them.” Even Sir David Attenborough comes under scrutiny for a scene in Blue Planet involving spawning lobsters that was supposedly filmed off the coast in Nova Scotia, but was in fact shot in a British aquarium, as well as for a couple of other, similar deceptions in other films.

I’ve blogged about the trouble with eco-porn more than once, but Bug Girl sums up the situation quite well, I think:

I have students showing up at the university that love the environment… but don’t want to go outside.
It’s hot! There are bugs and mud! And why aren’t any cool big animals doing interesting things? Everything just lies around. […]

Being outside is about Calm. Contemplation. Quiet.
Stillness and silence are not what television is about.

Except, of course, on the Undiscovery Channel.

None dwell in their tents

tent caterpillar on black birch trunk

Let their habitation be desolate; and let none dwell in their tents.
Psalm 69:25 (KJV)

Eastern tent caterpillars (Malacosoma americanum) are a common sight this time of year, especially in their last instar, after they abandon their tents. They stray onto the porches and wander over the furniture, looking for protected places in which to pupate. On a visit this past Monday, my three-year-old niece Elanor decided that they were cute — not typically my own reaction — and began petting them, prompting the caterpillars to arch their heads back like housecats. Yesterday afternoon, I watched one crawling up the neck and across the face of a box turtle, which merely shut one eye while the caterpillar took its measure.

tent caterpillar tree (black cherry)

The tents began appearing at the end of April in unusual numbers, especially on black cherry trees, which are the favorite food source for tent caterpillars and occur in unnatural abundance across Pennsylvania due to 150 years of clearcut logging practices and the reversion of old fields and pastures. Black cherry is a common first-succession tree species in many forest types, and thanks in part to its relative unpalatability to white-tailed deer, it can form almost pure stands in many areas that would have formerly hosted oak-hickory, beech-hemlock, or mixed deciduous forests. Here in Plummer’s Hollow, many of our southeast-facing slopes are dominated by black cherry stands, and I figured they’d be completely defoliated by this time.

blossoming black cherry

Instead, Sapsucker Ridge is white with blossoms, filling the air with an ambrosial scent. One finds only a few black cherries as badly defoliated as the one in the second photo; the tree above is more typical. Though dotted with tents, only scattered branches have actually been stripped of their leaves.

dead tent

A closer look reveals that most of these tents are filled with dead caterpillars. The few still alive twitch spasmodically. What happened? I’d guess that the unusually cold, wet weather over the past few weeks is at fault. Nighttime temperature routinely dropped into the low 40s this month, and sometimes even into the high 30s; daytime temperatures rarely exceeded the mid-50s; and rain was almost constant for the first three weeks of the month. Not only would the cold have shut down their temperature-sensitive digestive systems for prolonged periods, but the rain would have kept them confined to their silken tents, and the two together would’ve made them much more susceptible to starvation and disease. According to the Wikipedia article on tent caterpillars,

The tent is constructed at a site that intercepts the early morning sun. The position of the tent is critical because the caterpillars must bask in the sun to elevate their temperatures above the cool ambient temperatures that occur in the early spring. Studies have shown that when the body temperature of a caterpillar is less than about 15 °C [59 °F], digestion cannot occur. The tent consists of discrete layers of silk separated by gaps and the temperature in these compartments varies markedly. Caterpillars can adjust their body temperatures by moving from one compartment to another. On cool mornings they typically rest in a tight aggregate just under a sunlit surface of the tent. … Later on in the spring, temperatures may become excessive at mid day and the caterpillars may retreat to the shaded outside surface of the tent to cool down.

Entymologist Vincent G. Dethier’s wonderful and evocative classic, The World of the Tent-Makers: A Natural History of the Eastern Tent Caterpillar (University of Massachusetts Press, 1980) describes in Chaper 13 (appropriately enough) the battery of predators and diseases that keep this native insect in check. He details the spread of a deadly virus from colony to colony, then adds:

As if that were not enough the unusually wet late spring had been kind to molds, mildews, smuts, blasts, and bacteria. A particularly virulent spore-forming species of bacterium struck many of the colonies. … The enormous population of tent caterpillars had been cropped by weather, starvation, ants, bugs, parasites, fungi, viruses, bacteria, and misadventure in general. It had been a particularly trying year. Summer had hardly begun and the die had already been cast for the year to come. There would be fewer moths, fewer egg masses, and fewer colonies of the next generation.

So a spring that spells bad news for many farmers is good news for the wood products industry, which relies heavily on black cherry in Pennsylvania. Unlike fall webworms, which come too late in the season to have much of an impact on the trees they defoliate, tent caterpillars can greatly stress the trees they defoliate during their periodic outbreaks.

As global climate change plays hob with our weather patterns, it will be interesting to watch the effects on insect outbreaks, and over the long term, on forest succession. For example, if black cherries continue to predominate as many foresters would like, more-frequent icestorms would have a much greater impact than they would if less brittle species such as red oaks and tulip poplars took their place. Warm winters are said to promote the spread of pest insects, but what about warm winters followed by cold springs? I’d heard that the state was due for some pretty large gypsy moth outbreaks this summer as well, but here in Plummer’s Hollow, at least, their caterpillars are few and far between.

Cross-posted to the Plummer’s Hollow blog.

Scherzo for Winds


Scherzo for Winds, from the Undiscovery Channel

While I stand still as a gnomon trying to shoot the wind, five, six, seven chimney swifts wheel over the treetops up on the ridge, seining the air for wind-borne invertebrates: gypsy moth caterpillars on one-strand parachutes, perhaps. Baby spiders no bigger than an 8-point asterisk. Anything with wings.

A turkey vulture loses altitude above the corner of the field, rocking from side to side on upcurved pinions. Will it have to flap? No. It enters a thermal at last and spirals upward.

A common fritillary weaves drunkenly past my right shoulder, seemingly unconcerned by the sudden strong gusts throwing it off course. (Does it have a course?) I think a new verb is called for: it serendips.

From time to time, maple seeds come helicoptering in and disappear into the tall grass. The evidence of past years’ red maple profligacy dot the field, seedlings just big enough for the deer to find.

A sharp-shinned hawk sails out of the woods next to the powerline only to hover forty feet above the roiling sea of grass, wings fluttering rapidly, and then fly back. A cloud slightly larger than the others brings a spit of rain.

Lines for a cold May

question mark butterfly

first clear day in weeks
butterflies walk slowly over
the dry forest floor

interrupted forest

interrupted ferns’
delicate tips are still clenched
against the cold

pink lady's-slipper orchid

in the cold wind
a gnat clings to a bobbing
pink lady’s-slipper

leaf pond

tent caterpillars
the vernal pond quakes under
a coat of leaf-pieces

oak apple gall

oak apple gall
I bend down for a closer look
such a fresh green globe

The first two photos are from last week; the others are from yesterday evening.

A lifetime

You’re lucky to have a lifetime in one place, Dave — do you feel that way, or does it get to you sometimes?
Beth (via email)

I have sat on my front stoop for two hours, glass of homebrew in hand, and I can tell you that I am not in a hurry to move any place else. It’s finally sunny after many days of rain, but the temperature is still only 65 degrees in the shade, and the oak leaves have yet to reach their full extent — hell, the black walnuts and black locusts have barely begun to open. I wish every spring took its time like this! I watch a bumblebee have intimate relations with the fresh pink blossoms on a bleeding-heart. A male ruby-throated hummingbird hurtles up and down, back and forth in his U-shaped courting flight, like the pendulum of an invisible clock. I watch a rose-breasted grosbeak singing as he flies, the red triangle on his breast catching the sun like a tribute to the 40th anniversary of May 13. (Damn, I was only two years old in 1968!)

A sharp-shinned hawk circles with that peculiarly rapid flapping they do, rising from the vicinity of my parents’ back porch to disappear into the slipstream above the ridge on wings of gold. A little later, a turkey vulture glides past. I watch innumerable flying insects backlit by the sun, all drifting in the same direction, west to east, in the almost imperceptible breeze. And all the while I listen to Roscoe Holcomb piped over the Internet, that high-lonesome Appalachian blues sound. At a certain point my eyes tear up: I can’t help thinking of those tens of thousands dead in Burma and in China. Poor fuckers. Whether you live on the coast or in the mountains, the land you love can turn on you at any time. That’s kind of what I was trying to get at with my last poem — the way we are bound to a particular place on this earth, even if we are a party to its undoing, and find it devilishly hard to pick up stakes. I mean, those folks in Picher, Oklahoma: Jesus Christ.

I like the way alcohol makes me feel content and dissatisfied at the same time. Newly energized, I get off my ass and pull a bunch of weeds just as the sun is going down. As soon as it slips behind the western ridge and the shadows disappear, the catbird flies to the top of the tallest locust in the yard and begins to improvise. Beth, since you asked: it gets to me every day.

Trees of life


Flowering Crabapple, from the Undiscovery Channel

There’s always something a bit paradisaical about a fruit tree in flower, abuzz with insects of every description. The aural and visual stimuli combine with the heavy scent and the electric atmosphere to create an almost overwhelming impression of superabundance. How can the world not be good, we think. I’m sure someone who grew up in the Midwest would argue with me on this, but I just don’t believe one can experience the same kind of gestalt in a field of wheat.

It’s worth recalling, perhaps, that for a very long time our main vision of paradise was arboreal. The central truth of the Garden of Eden story is that the loss of paradise was and remains wholly preventable, and that it finds expression most often in the misuse of trees. Nowadays, of course, for all but the willfully ignorant, evolution teaches that we are primates, descended from the trees: a not incompatible truth. One way or another, the wholesale destruction of forests is something that few human beings can regard with equanimity. And quite often, as in the mythical Eden, it dooms us.

Consider landslides. Hundreds of thousands of people, at the very least, have been buried alive after the slopes above their houses were logged, from Oregon, to China, to the Philippines, to Indonesia and various parts of the Himalayas.

Officials in the wildlife and forest department of Azad Jammu and Kashmir, (AJK) are of the view that an estimated 30 percent of the 87,000 people who died in the magnitude 7.6 earthquake [in 2005] could have been saved if there had been fewer landslides.

The officials, who declined to be named, blamed deforestation of the area for the huge landslides that contributed to a death toll that has risen to 43,399 people and left 31,069 others injured in the AJK districts of Muzaffarabad, Neelum, Bagh, Rawlakot and Palandri.

Then there are storm surges. The loss of coastal mangrove forests in parts of south and southeast Asia appears to have greatly magnified the destruction of the 2004 tsunami, according to a peer-reviewed study in the journal Science.

“The tsunami left a horrific human tragedy in its wake but also some lessons. Among them is the tremendous importance of mangroves, which are one of the world’s most threatened tropical ecosystems,” said Faizal Parish, director of the Global Environment Centre in Malaysia and co-author. “While no one could have prevented the tsunami, we can use this experience to prevent some of the destruction future events will cause.”

Unfortunately, that experience didn’t come soon enough to protect tens of thousands of Burmese villagers from the storm surge associated with last week’s cyclone. There, too, it appears that the destruction of coastal mangrove forests was as much to blame for the heavy death toll as the storm itself.

If only knowledge and experience by themselves were sufficient! But as the Garden of Eden myth suggests, we know just enough to be dangerous, rarely enough to be wise. Here in the U.S., we’ve understood the tight relationship between forests and water for over a hundred years. George Perkins Marsh’s hugely influential Man and Nature, published in 1864, used the historical example of forest destruction around the Mediterranean to finger deforestation as the leading cause of desertification. The catastrophic landslides, floods and fires that followed widespread clear-cutting in the latter half of the 19th Century here in the eastern United States seemed to many people to bear out Marsh’s prophesies, and led directly to the founding of the U.S. Forest Service. Yet today, most administrators of the USFS define “conservation” as “getting out the cut.”

The Pennsylvania state forest system, like the Adirondack Forest Preserve in New York, was established with the principal goal of preventing floods and erosion, protecting navigable waterways, and guaranteeing a clean water supply for the residents of the state. The link between intact, older forests and a steady supply of clean drinking water was very well understood, and countless studies since have only served to reinforce this insight. Preserving wide forested buffers along streams and rivers, for example, has become a standard water purification strategy, albeit one honored most often in the breach. But professional foresters are still advising municipal water authorities around the state to log portions of their watersheds “for the health of the forest” — defining “forest” solely in terms of saleable timber, and “health” in terms of profitability — with a deterioration in water supply as an inevitable result. Perhaps they figure that, since everyone buys water in plastic bottles now, it doesn’t really matter.

Marsh was right in more ways than he could possibly have imagined. Deserts are on the march all over the world, their progress greatly accelerated by, if not wholly attributable to, the cutting of trees. And as I mentioned last week, unlogged forests are an essential part of the global carbon cycle as well. I’ve seen widely varying estimates of the contribution of deforestation to global warming, but one of the most recent and conservative, again published in Science, asserts that “nearly 20 per cent of carbon emissions [are] due to human activities.” How much more evidence do we need that trees are essential to our continued life on this planet?

I am, quite obviously, a tree hugger: one of those soft-headed people who actually thinks trees deserve to live for their own sake, and who recognizes that they are the keystones of complex ecosystems supporting millions of species besides Homo sapiens, each of which has as valid a claim on the planet as we do. You can disagree with my value system all you want. The simple point I’m trying to make here is that even from a purely anthropocentric perspective, deforestation is one of the quickest, surest tickets straight to hell.

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Don’t forget to submit tree-related links to the Festival of the Trees, hosted next month at the inimitable Wrenaissance Reflections. Details are here.

Carbon credit accounting

Science is beginning to confirm what many of us have long suspected: that older forests are better at sequestering carbon than younger ones, contrary to what some foresters would have us believe. My father has been wondering lately whether our own few hundred acres of forest are enough to offset the carbon we produce as a family. If you know my dad, you won’t be surprised to hear he’s got it all more or less figured out.

We are coming under intense pressure here in the Appalachians to clear every ridgetop forest for wind turbines, but I suspect that we can make the biggest difference simply by leaving the forests the hell alone. Certainly the best thing we could do for the forests themselves would be to end all extractive uses and employ foresters and loggers to conduct taxonomic surveys and ecological monitoring instead. Considering how much we still don’t know about Appalachian biodiversity, and how much we stand to lose as a result of global climate change, those are the kind of “green jobs” most desperately needed right now.

Rhoneymeade

bust

Yesterday I finally paid a visit to the Rhoneymeade Arboretum, Sculpture Garden, and Labyrinth, which is about 35 miles northeast of here, right out in the middle of a farm valley. The only other sculpture gardens I’ve visited have been those attached to major urban museums, so I was interested to see what difference, if any, the rural location might make.

blue atlas cedar

Well, for one thing, not all sculptures here are made by humans. Also, trees both native and exotic take pride of place in the garden and in the nearby labyrinth, a refreshing shift in emphasis from most modern presentations of Art, where nature plays a supporting role at best.

Flight

Nor were all the human sculptures either anthropomorphic or completely abstract, though the majority did fit into one of those two categories. “Flight” was one of a half-dozen or so that seemed to take its surroundings fully into account.

Brown Man 2

The birds here do what birds always do to public statuary. This plaster and resin sculpture is identified as “Brown Man” on the website, but “Thoughtful Man” on the laminated directory in the studio at Rhoneymeade itself. One way or another, it’s obviously getting lots of attention from the local birds.

Brown Man 1

The plaster was beginning to fall off in a couple of places, and the grass had been left to grow long around it. Given its manner of composition — a life cast from a living model, according to the owner — I imagine that the artist fully anticipated its slow return to nature.

Complete set of Rhoneymeade photos (9) / Slideshow