Nieuwe ziekte in Nederland

[treespotter]

Volgens mij is onderstaand bericht ook reeds van toepassing in Nederland.
Ook hier heb ik reeds een aantal bomen zien aftakelen door deze symptomen en zal het in Nederland binnenkort ook wel op het Nederlandse lijstje komen te staan naast de Pseudomonas aantasting in de kastanjes.
Ik heb ter illustratie twee foto's bijgevoegd van dezelfde boom met een aantal jaren ertussen.
De zwammen op de stam (onderste foto) zijn dus niet de eerste aantaster, maar een secundaire (of nog latere) aantasting.

Beech Bark Disease on Eco-Invader List

(AP) -- Tracy Casselman runs a hand over the smooth, gray bark of an American beech, noting the scratch marks left by black bears that have clambered up the tree to munch nuts rich in fat and protein.
Perhaps 80 years old, a couple of feet in diameter and 60 feet high, the beech appears robust, like many of its neighbors scattered near a two-track road in the backcountry of Michigan's Upper Peninsula. But appearances are deceiving. These trees likely are doomed.

"Take a good look," says Casselman, manager of the Seney National Wildlife Refuge. "In five years, these trees won't be here."

Beech bark disease has taken hold in the refuge, a dagger aimed at the heart of a stalwart native hardwood. The American beech has relatively little economic value for people but plays a starring role in the natural drama acted out daily in Michigan's northern forests.

Scientists expect the disease eventually will kill most of the state's beeches, changing the environment in ways as yet uncertain. For example, it could affect populations of bears and smaller mammals that feed on beech nuts - and that hunters enjoy pursuing.

"Obviously there will be a shift in the ecology of the forest," says Robert Heyd, forest health specialist with the Michigan Department of Natural Resources in Marquette.

Beech bark disease has been overshadowed by the emerald ash border, a murderous insect wreaking havoc on trees in southeastern Michigan and creeping steadily northward.

But both have something in common with the zebra mussel, purple loosestrife, round goby and spiny water flea: They are foreign species, introduced to the Great Lakes region through human carelessness, and are crowding out natives and profoundly altering the ecosystem.

"When I was in college, I could name maybe half a dozen exotics," Casselman says. "Now I could spend 10 minutes rattling them off. I just wonder when people are going to recognize the cost of bringing all these exotics in."

Federal studies say more than $120 billion is spent yearly in the United States controlling about 800 invasive species and repairing their damage. And the environmental losses - extinction of native plants and animals, less biodiversity and natural beauty - are incalculable.

Debate continues over preventing new invasions through measures such as limits on ballast water dumping by foreign ships in Great Lakes ports. Tighter controls on ornamental plant imports would be helpful, says Michael Lusk, invasive species coordinator for the U.S. Fish and Wildlife Service, who inspected stricken beech trees at Seney last fall.

"In Australia and New Zealand, you can't bring in anything until you prove it is not going to be invasive, it won't hurt what's already there," Lusk says. "Our laws say you can bring in anything you want and once we have a problem, you put it on a list and stop importing it."

Beech bark disease slipped into North America in 1890, courtesy of ornamental trees shipped from Europe to Nova Scotia. Over the next century and more, it moved across eastern Canada and south to New England, New York, Pennsylvania and West Virginia. Spot infestations have turned up even farther away, including Ohio.

The disease was discovered in Michigan in 2000. It was first noticed in Ludington State Park on Lake Michigan and in Bass Lake State Forest Campground near McMillan in the Upper Peninsula, which suggests it could have arrived in firewood brought by campers from elsewhere - also a likely culprit in the emerald ash borer's movement.

"Bears are omnivores, so I don't expect a big impact on them," staff forester Greg Corace says, gazing at a snapped-off beech in an area infested with the invasive scale. "But some species may be less adaptable. We just don't know what will happen, but we suspect it isn't going to be good."

"It can kill 75 to 80 percent of the (beech) trees in a given area," Lusk says. "Once it's there, it's everywhere. You're done, you're cooked."

Beech bark disease actually happens in two stages.

It begins with tiny scale insects that feed on sap in the tree's thin bark. Heavily infested beeches are noticeable by the white wax that covers the scale, creating a woolly appearance.

The scale injures the beeches, making them vulnerable to a fungus called nectria that kills tissue and often entire trees.

Heavy winds sometimes cause "beech snap," in which weakened trunks break in half. To protect hikers, authorities removed more than 200 beeches along trails at Tahquamenon Falls State Park, says Deborah McCullough, forest entomology professor at Michigan State University.

"As far as trying to slow (the disease) or contain it, not much can be done," McCullough says. DNR forest managers are thinning large beech stands in hopes of impeding its progress.

One hopeful sign: For unknown reasons, some beech are proving resistant to the disease. Scientists are studying them in hopes of developing hardier strains that could be planted to rejuvenate the species, Heyd says.

Beech are not the most prevalent of Michigan hardwoods. They're found most often within areas classified as maple-beech-birch, which make up about 7.2 million acres of the state's 20 million acres of forestland, Heyd says. In such areas, maple and birch tend to outnumber beech.

As a timber product, beech wood is used primarily for niche items such as bowls, says Tom Barnes, executive director of the Michigan Association of Timbermen. It sometimes turns up in furniture and flooring and is prized as firewood.

But its ecological value is considerable. Cavities in the older trees provide habitat for birds, fishers and pine martens. Hawks and eagles perch on their stout limbs. Triangle-shaped beech nuts are a crucial nutrient for many birds and mammals, including squirrels, deer, foxes, ruffed grouse, ducks, turkeys, bluejays and warblers.

There's no readily available substitute for beech nuts as a food source in the 95,238-acre Seney wildlife refuge, a patchwork of woods, fields and wetlands teeming with waterfowl.

Managers acknowledge they don't know how the loss of most or all beech trees would affect the refuge's animal populations.

Dit bericht is ongewijzigd overgenomen van www.physorg.com

Groeten

Wolter

[treespotter]

Volgende foto van de Beukenbastziekte.

[mennie]

kelerig, wolter welke bomen ziekte volgt er nu? na iepen, kastanjes en nu de beuk? blijft er dan niets veilig?

[treespotter]

O, jawel hoor....

Er worden steeds meer van die mooie bomen geplant. Je weet wel, van die slanke met een mooie groene of zilveren stam.






En als het donker is geven ze nog licht ook, met energie vanuit een fossiele brandstofcentrale die er voor zorgt dat de temperatuur hier zo lekker omhoog gaat en dat er in sommige delen van de wereld weer voldoende water is.

En weet je wat ook zo leuk is? Al die klagers over schaduw, die zitten 's avonds lekker in het licht met die nieuwe soort bomen

[chestnutnut]

onlangs heb ik dezelfde symptomen ook vastgesteld op beuken en eiken in West-Vlaanderen.
het lijkt erop dat deze Pseudomonas syringae stam de paardekastanjes gebruikt als springplank naar (voorlopig) minder gevoelige soorten.
overigens werd deze vorm van aantasting in Engeland al een tiental jaar geleden gerapporteerd en de mortaliteit onde paardekastanjes was toen in de orde van 10%.
wel erg, maar toch geen doemscenario.

[treespotter]

Het percentage aangetaste kastanjes lag geloof ik in midden-Nederland vorig jaar al op ongeveer 50% Joe. Hoeveel het nu is? Ik heb geen idee, maar die 50% zijn wij al lang voorbij. Wat ik wel weet, is dat ik een erg blij gevoel krijg als ik weer eens een keer een onaangetaste kastanje zie. Wat ik ook zie is dat het patroon van aantasting van andere boomsoorten wel erg lijkt op de Pseudomonas aantasting van de kastanje, zo'n 15 jaar geleden. Ik moet wel zeggen. Ik ben ook al beuken tegengekomen waarop de zwarte vlekken aanwezig waren, waar ik aan de boomeigenaren heb gezegd dat zij maar 'alvast afscheid' moesten gaan nemen omdat het een aflopende zaak is. Dat die beuken er nog in goede gezondheid bij staan en dat de zwarte vlekken zo goed als verdwenen waren. Ik durf geen levensverwachting uit te spreken bij dit soort aantastingen. Het klinkt als een open deur, maar ik noem de mogelijke slechte afloop en hoop met de boomeigenaar op het beste.