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American Forest Before the Chestnut Blight

Once upon a time, American deciduous forests were filled with a magnificent tree, the American chestnut tree.  It is estimated that, prior to the twentieth century, a quarter of the trees in the forests of Appalachia were chestnut trees.  The trees grew to 30 metres (98 ft) in height and were prized for giving stout timber and large quantities of delicious nuts.  They were also renowned for their beauty.  But then, something bad happened.  In 1904, some Asian chestnut trees were planted in the Bronx (in what is now the Bronx zoo).  These Chinese chestnut trees had a pathogenic fungus, Cryphonectria parasitica, living on them.  Chestnut tree species of Asia have evolved some defenses to this rapidly spreading fungus, but the two American species were completely unprepared.  By 1950, the blight had killed more than four billion trees and only strange isolated single specimens and sad still-living (yet undead) stumps remained.  The chestnut blight opened our eyes to the perils of invasive species in a world of almost-instant shipping (although I don’t think we have yet fully understand how pervasive and potentially dangerous fungi can be), it also marked an irreversible change to our beautiful forests…

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Evidence of the Chestnut Blight!

Except maybe not.  Molecular biologists, mycologists, and arborists have been quietly working for years to hybridize a blight-resistant modern American chestnut tree.  They failed at hybridizing a vigorous tree with the desired characteristics of the original American chestnut trees, so they turned to transgenic tinkering and this technology has yielded results.  The American Chestnut Research and Restoration Project at New York state’s College of Environmental Science and Forestry has utilized the same sort of technology behind genetically modified crops (like BT rapeseed and such) in order to create American chestnut trees which have a gene from wheat that helps the trees survive and tolerate Cryphonectria parasitica.  The American Chestnut Research and Restoration Project is readying an army of these genetically altered trees to go into the wild forests and reseed North America as it used to be, but their plan is not without controversy.

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Some opponents worry (understandably) that bringing back the chestnut will represent “a massive and irreversible experiment” on our living forests.  Additionally, as we know from the hysterical response to transgenic crops in Europe and even here, many people are extremely emotional and ill-informed about gene-manipulation technologies (probably because the phrase “gene-manipulation technologies” sounds so much like a 1950s horror movie tagline).   Transgenic blight-resistant American chestnut trees still need regulatory review from the Food and Drug Administration (and maybe the Environmental Protection Agency) before they can be planted and allowed to disperse pollen.  Such a process may take many years.  Yet tree lovers and concerned ecologists point out that the near-extinction level mass deaths of American chestnuts was caused by humankind’s actions and choices.  And more blights are arriving every year to destroy other cherished species of trees.  We live in a world of emerald ash borers, Dutch Elm Disease, spotted lantern flies, gypsy tent moths, and oak wilt.  If we don’t start doing something, the only tree left might be the diabolical invasive tree of heaven (I can’t believe nobody commented on that post! Am I the only person to despise that nightmarish monster?).

The regulators are starting to analyze the proper course of action, and I guess we will be hearing more from them, but, in the meantime, what do you think?

 

Gros Michel Bananas

Gros Michel Bananas

A half a century ago, bananas were more delicious. They were creamier with a more delectable tropical fruit taste. When they ripened, they stayed ripe longer instead of swiftly turning to black slime. Since they lasted on the shelf when ripe it was possible to sell them ripe–as opposed to today’s bananas which must be purchased all green and hard and nasty. I realize that this description makes it sound like I have fallen prey to golden age syndrome—wherein a bygone time becomes a misremembered quasi-mythical standard against which today is unfavorably compared (a well-known problem for certain political parties and demographics)—yet I am not embellishing. The bananas of yore were better because they were different. If you recall the earlier banana post, you will remember that there are numerous strange and magnificent varieties of bananas in Southeast Asia—delicious miniature bananas, red bananas, purple bananas…all sorts of fruit unknown to us. For long ages, across many lives of men, farmers hybridized wild species of bananas and selectively bred the different strains into different varieties called cultivars. The most delicious and salable cultivar was “Gros Michel” (Fat Michael) which I described above. “Gros Michel” was so ideal for farming (and so tasty) that it became pretty much the only banana cultivated. Vast plantations around the world produced only “Gros Michel.” It grew on large 7 meter tall trees (21 feet) which produced abundantly.

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I even have a family story of how my paternal grandparents got together during World War II. He finally expressed his interest in her by giving her a banana—which were rare and precious during the war. Grandma was suitably impressed and made a somewhat ribald poetic metaphor concerning the banana’s shape–which left grandpa with no doubts about her feelings…which is to say I am considerably in debt to “Gros Michel”, despite the fact that I have never tasted one.

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So what happened to Gros Michel? Is there by chance a terrifying horror story which provides us with a useful moral lesson about our tastes, our habits, and the fragile nature of the foundations of civilization?

Well, as it happens there is such a story!

Banana Tree with Panama Disease

Banana Tree with Panama Disease

In the 1950s, a fungus Fusarium oxysporum attacked the Gros Michel bananas. It was known as “Panama Disease” and it wiped out entire plantations of fruit in Africa and South America. The blight spread with horrible speed through the great monoculture farms. All Gros Michel bananas were clones, so the contagion spread unchecked. There were years where there were almost no bananas in Europe, Africa, and the Americas: whole empires turned to ashes and rot. To save their livelihood banana growers burned their groves and moved to a new dwarf banana “the Cavendish” which was unsatisfying—but which resisted the terrible killing fungus. Gros Michel disappeared from the commercial world…although there are tantalizing rumors that it exists still in the ancestral homeland of bananas—Southeast Asia. It has even been said that Chinese billionaires import luxurious Gros Michel fruits and have lavish banana parties where they eat magnificent tasting bananas and laugh at the feeble little green bananas of the west.

dsc_1801banana_shopWhatever the truth of these tales, what is certain is that the banana growers outside of Asia immediately fell back into their bad habit of monoculture. The Cavendish is just as vulnerable to blight as its predecessor. Indeed many monoculture crops (crops like wheat, rice, and potatoes) are potentially vulnerable to unexpected disease because of the perils of overreliance on certain favorable strains. It is a somewhat sobering thought for people who eat!

My garden in Brooklyn at the end of June.

My garden in Brooklyn at the end of June.

My summer garden looks a lot different this year for two reasons.  First of all, the hydrangea finally started blooming!  It has magnificent human head-sized blossoms the color of blueberry ice cream (or maybe I should say the color an alien gas-giant planet) and I love it.  I thought the poor thing was dead for a year and a half but now it is the centerpiece of the garden!  There is an allegory about hope in there somewhere.

The second big change is more disquieting.  In shade gardens, the best way to get a colorful ground cover is to plant impatiens—tiny jewel-like five petal flowers which easily grow into a dazzling multicolor carpet. Because they are cheap and hardy (and beautiful–despite what flower-snobs say), I usually carpet my beds with them.  But this year things went very, very wrong for impatiens.   A deadly strain of downy mildew has struck down happy little impatiens across the nation and beyond.   The pernicious fungus is named (Plasmopara obducens) and it has spread like an Old Testament plague through the United States and Great Britain (as painfully detailed in this excessively wordy NY Times article).  I bought a few flats of impatiens from the hardware store at the beginning of spring—but after that there were no more.  I fret that the little red and pink flowers could fall dead at any moment.

Vinca "Jams 'N Jellies Blackberry" (that doesn't get easier to write)

Vinca “Jams ‘N Jellies Blackberry” (that doesn’t get easier to write)

To make up for all of the coral and purple impatiens which I never got a chance to obtain, I bought a bright white New Guinea impatien (which you can’t see in the photo up there) and it is magnificent, however it was so expensive that I only bought one.  I filled up the remaining beds with weird purple-black vincas agonizingly named “jams ‘n jellies blackberry” (who comes up with these names?  Maybe the seed companies should hire some of my poet roommates).   The vincas are growing very slowly.  It is unclear if they will be able to set roots and flourish before the evil squirrels dig them all up.

New guinea impatiens are so pretty!

New guinea impatiens are so pretty!

So my garden is all ferns, Persian shields, caladiums, vincas, and lilies.  I am hopelessly drifting back towards Victorian England while the rest of the world is going all ahead towards ultra- cyber-hip-hop (which is represented in the garden by what exactly? picotee morning glories, track lighting, and giant aluminum cylinders maybe?).  Anyway I also planted some weird autumn plants—passionflower vines and toad lilies—so check back in late summer to see how those turn out!

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One of the problems with writing about living things is that there is a lot of troubling news from the natural world.  If one writes about the many sad or perplexing  issues affecting worldwide ecosystems, people get depressed and stop reading, but if one willfully ignores true problems…well, what is the point of observing and thinking about the world?  I remember CNN’s online newspage used to have a Science/Nature header which was so consistently filled with news of species die-offs, ecological disaster, and worldwide blight that the whole science section was canceled.  Now CNN has more room for “news” about Ashton Kutcher’s all fruit diet and a tech section with reviews of “cool gear” you can buy for your Superbowl party.  Sigh….

All of which is a round-about way of apologizing for today’s upsetting (but extremely important) post concerning the mass die-off of North America’s bats.  Wait! Please don’t go to other site to read about “Miley” Cyrus.  Bats are actually really important. They are key organisms in ecosystems across the continent.   If they all die, the rest of us mammals are also going to be in serious trouble

The culprit behind the bat deaths is a fungus, Geomyces destructans, which causes WNS–white nose syndrome.  Despite its cartoonish name, white nose syndrome is a horrible death sentence for most temperate bats in North America.  Geomyces destructans is a low temperature fungus (like the hideous specimens you find in neglected refrigerators).  As the bats hibernate, powdery white fungus builds up on their little wings and faces.  The poor itchy bats are awakened from hibernation and, because of the irritation, they cannot return to a suspended state.  The little animals quickly burn up their energy reserves and die—to then become macabre bat-shaped clumps of fungus.

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Geomyces destructans seems to have traveled to North America from European caves, probably on the boots or specialized equipment of spelunkers (strange troubled sportspeople who worm deep into the crushing dark of caves).  Now that the fungus is in North America, it appears to be spreading by means of bat to bat contact.  European bats seem to have a native resistance to the fungus, but American bats are unprepared for it and they have died in legion.  Ninety percent of New Jersey’s bats are believed to have already died.  As the plague moves to new colonies similar mortality is expected.  Although the disease started in the middle of New York State, it has quickly spread along the East coast and it is moving west.   Scientists worry that the pestilence could spread from coast to coast (although bats which live in warmer climes might be less susceptible to the low temperature fungus).  Bats reproduce slowly—usually at a rate of one pup (or less) per year, so bat colonies cannot replenish like sardine schools or rodent colonies.  Additionally the spores linger in caves even after all the bats have been killed.

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I personally love bats.  I find them endearing and beautiful (and relatable, since I have my own flighty nocturnal habits).  Western culture has not been so kind and often equates the flying mammals with witchcraft, Satan, demons, and all other manner of underworld fiends (the Chinese, however, see bats as lucky—in fact one of the Eight Taoist immortals began his cycle of incarnation as a bat).  A surprising number of Americans cleave to the old ways and smile at the horrifying curse that jackass cave explorers have unknowingly unleashed on our little chiropteran friends.

This attitude is a big mistake.

Anecdotally, the weather on North America has been worsening.  Great storms pound our coasts, droughts scorch the hinterlands, and mighty cyclones appear everywhere knocking down forests.  Imagine if, to compound these woes, vast plagues of insects descended upon our homes and crops.

Well, without bats, you won’t have to imagine.   Bats are a principal predator of insects—especially nighttime insects like mosquitoes (but also a surprising number of agricultural and forest pests).   Humans, being diurnal, underestimate bats, but insect-eating chiropterans eat 80% to 100% of their body mass in insects per night and they live in vast colonies (especially out west). Without bats we are liable to see great swarms of insects eat our crops and we will experience a resurgence of mosquito born ills.

The pallid bat (Antrozous pallidus) Photography by J. Scott Altenbach

The pallid bat (Antrozous pallidus) Photography by J. Scott Altenbach

An article in Daily Finance outlines some of the potential fall out of the great North American bat die-off (and if cold heartless financiers are worried about the environment, we know that something is really amiss).  So how can we actually help the bats? The Federal government has allocated 1.6 million dollars to study the problem, but this is not a lot of money!  Various agencies and organizations are attempting to curtail cave exploration and keep people from becoming a further vector for spreading the fungus.  Making people aware of the problems bats are facing is also a useful step (which is why I am writing this).  Most of all we need to care for bats before they are gone.  Farmers, bankers, politicians, ecologists, and scientists all need to worry about our beleaguered friends. The mass die-off of honey bees has had a horrible effect on agriculture and forestry:  the effect of a bat die off could be worse.  But even more importantly bats are social mammals—like us.  If suddenly 90% of them are dying off, it is a terrible portent as well as a horrible loss to the planet.

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