Chalara fraxinea, ash dieback
Making an Ash of Themselves?
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No one was present to note the arrival of Chalara fraxinea in Zabodny, Poland, some time prior to 1992. Since then, the deadly fungus disease commonly called ash dieback has run rampant through Europe killing almost every ash tree its spores have alighted upon. More recently it has threatened the ashes of Britain.
Over the past few months, it has been almost impossible to pick up a British paper and not discover reports of its potential impact on the United Kingdom. Scientists have warned that an outbreak there has the potential to devastate the UK’s population of 80 million ash trees, Fraxinus excelsior.
In good health, the European ash is an impressive tree, towering as tall as 40-metres (130-feet). Man was created from the ash tree, recounts Nordic mythology; aska is the Norse for ash wood. They and others valued it for spear hafts as well as staffs of the kind that Robin Hood used to battle with Little John. It is resilient, rarely warps or splits and so was formerly used in the construction of ploughs, carriages and wagons. Even today it is valued for superior tool handles and walking sticks. Ash with its excellent burning quality also supplied the traditional Yule Log.
A tea or tisane made from the bitter bark was used in times gone by to treat rheumatism and liver complaints. Similar preparations of leaves were believed relieve dropsy as well as being an early weight-reducing nostrum, one herbalist suggesting three or four leaves taken in wine every morning. The seeds or ‘keys’ were recommended against flatulence and, picked young and fresh, as an unusual pickle.
Not for much longer. Having killed up to 90 per cent of all native ash trees in Europe it threatens to do the same in the British Isles.
But until recent months, the authorities there chose to emulate the ostrich and bury their collective heads in the sand. “Officials were warned four years ago about a fungal disease which threatens to devastate Britain’s 80 million ash trees but failed to act to halt its spread,” claimed The Daily Telegraph on 30 October last. A day later, the Daily Mail had taken up the ash cudgel with the provocative headline: “Labour Knew Four Years Ago About Ash Tree Threat But Didn’t Act: Ministers Hid Behind European Law.” The paper explained that, “One campaigner wrote to ministers in 2008 to warn about the danger to forests of the unrestricted import of foreign trees, but the government at the time took no action.”
In fact, experts admitted, Chalara fraxinea had been in the country for at least a decade, although some experts believe it originated in Japan, where it is not lethal to ash trees. As it spread from woodlots into back gardens, it became a matter of public concern. Government instinct was to blame imports of nursery stock from the continent. Panicking officials ordered stock to be burnt. Simon Ellis of Crowders Nursery in Horncastle, Lincolnshire was forced to destroy 50,000 ash trees. Now he will be suing for more than £200,000. Other growers are following with a total bill of perhaps £10-million, to be taken from the taxpayers’ collective pocket, malheureusement.
Experts gathered, committees formed, advice spewed forth. Compost all ash leaves, suggested some. Composting doesn’t destroy the fungus spores but burning does, recommended others. A government minister, no less, urged the public to wash their dogs and boots and even their children after visiting wooded areas.
Culling was resorted to. In a single week, 100,000 ash trees were destroyed. Homeowners faced enormous costs to remove dying and dead trees from their gardens.
Despite everything it has become obvious that the disease is now beyond containment. But despite wailings of doom and gloom from the usual culprits, the answers are out there.
A recent Swedish study in the Scandinavian Journal of Forest Research has revealed crucial information for horticulturalists in the U.K., and in Northern and Central Europe, in their battles against Chalara fraxinea fungus, noted online Science Daily. Results of the study are far reaching, encouraging governments to invest in ash breeding programs that will all but eliminate the disease.
Researchers have also developed a low-cost solution that could control the fungal disease, again according to Science Daily. Initial tests have been carried out at Imperial College London’s Silwood Park Campus in Berkshire and will continue in spring of this year. The product is called CuPC33 – a solution of copper sulphate and other minerals.
Before breathing a sigh of relief, Dr. Joan Webber, Head of Tree Health at the Forestry Commission in Britain has noted that ash dieback is just the latest disease or pest so virulent that it threatens to wipe out entire species. She has catalogued 10 further problems – nine diseases and a single pest that could devastate trees in the U.K. Five of those are forms of Phytophthora, one of which, P. ramorum, is responsible for the sudden oak death (SOD) rampaging through the West Coast of North America. And, adds Dr. Webber, there is the potential threat of at least a further 11 deadly diseases “on the horizon.”
Perhaps the ancient Norse were right and man is descended from aska. Certainly in some situations he has been spreading tree pathogens ever since, thus assuredly making a silly ash of himself.