Hey, what’s all this about the death of the Ash?
All the media in the UK are full of the story and most are quoting Danish arboricultural experts who tell of their recent loss of 90% of their Fraxinus excelsior. THAT IS SIMPLY CARELESS! Or, indeed, it has happened so quickly that they could not stop it.
OK, now the infective culprit – a fungus they tell us – has been found on imported ash saplings in nurseries in the UK – East Anglia first but possibly elsewhere, too. To protect the region 100 000 ash have been “felled” or otherwise removed (most were just nursery lined out or recently planted saplings.)
Now I’d think this was just a ten minute panic, to sell newspapers and amuse wardens, if I hadn’t seen the Death of Elms in the 1980s when vast tracts of land in the UK were decimated by the loss again to a fungal infection. Dutch Elm Disease, DED, was an epochal event and fairly quick, too.
Well Danish Ash Disease, DAD, is found in other Northern European countries, too, and also increasing for them, although not to the drastic Danish 90% yet. For a second such fungal infection to spread through a well adapted and widespread species, such as the Ash is, would be catastrophic and can only be an indicator of the subtle adaptations of species to their own local ecosystems.
In my native tree nursery, written about previously (Running a native tree nursery, Feb 2012) I stressed how it was a fundamental principle that all planting stock should be of local provenance seedstock grown locally to enable accurate and healthy establishment in the chosen environment. This was based upon a lot of personal observations of such events.
In my own plantings of nursery purchased saplings I have seen unfortunate performances. The classic is Crateagus monogyna, Hawthorn which, although I bought the saplings from a nursery in Welshpool, less than 100 miles away, I later found they’d imported the saplings in bulk. Now, some fifteen years on, these young trees still come into leaf two weeks earlier than the Hawthorn which already grew on the site. Flowering is also earlier. Clearly this can disadvantage the foreign trees and leave then more prone to frost damage or missing pollination insects, having profound knock on effects to the ecosystem.
I have witnessed the same problems in Fraxinus excelsior as this is the species I wrote a detailed research paper on in which I compared the performance of a dozen subgroups of the tree grown from seed sourced all over Western and Central Europe. ( “Phenotypic variations in Fraxinus excelsior from different European provenances”, Chris Hemmings, UCW Bangor, 1999, available as pdf by email – please contact me if required – firstname.lastname@example.org) Two hundred seedlings from each site were grown on two common plots, one in North Wales and a second in North Yorkshire. The saplings of each origin were grown in intact blocks of ten by ten, the whole thus as an array of grids.
Much detailed measurement of the then seven year planted out saplings showed dramatic differences in performance with the suggestion that one could discern in the more Northern and Eastern origins slower growth and greater tolerance of drought. Suffice to say it was at once clear when one moved from one origin’s “box” into the next.
So often when you go to follow up that happy public planting session where the mayor and hundreds of volunteers had a year or two ago “created a new woodland” you find the majority of the new plants have perished. Clearly if the plants have not been grown from seed of local provenance then subtleties of the plants’ genetics are just wrong and the new plantings are more easily rejected. Could establishing a new woodland thus be more like a skin graft than has before been realised?
Anyway, if Ash saplings imported from the continent are not only genetically wrong but are also carrying alien fungal tissue the “grafts” will surely fail. Cleverer nurseries, of course, actually import seed. So a Dutch nursery can sell you saplings grown from seed sourced, say, in Snowdonia. But they’re still going to experience foreign fungi – unfamiliar to their genetic programmes – which could be, thus, well established/ingrained before you import them. Planted out the fungi can readily then flourish and kill off the new and fragile plantings. They’re less bothered where they grow and transplanted saplings lack any established root systems within the soil structure.!
DED took down acres of established Elm. It went first for young trees, especially in the Spring when sap was rising and later for older, maturer, even ponderous trees. But pretty much all went over maybe ten years. This arose “from spores on timber imported from Holland”. Some said that a greater environmental frailty existed, rendering Elm open to this infection. Seemingly there was no effective integral defense mechanism available against this particular fungus, delivered by a particular boring beetle deep into the bark.
But really, you’d have expected otherwise. Tough, tried and tested species, well adapted and totally part of the landscape felled by humans causing contamination between distant ecosystems. DED could have had a far eastern origin and subsequent mutation or cross to another fungus to create the particularly deadly strain. Certainly, it seems, it would not have occurred in a World undisturbed by human trade.
If that’s the origin of DAD then who knows what will happen. We’ve not really recovered from DED – loss of all or most of our Ash would be a disastrous blow and would it not then just be a matter of time before we lost the Oak, as well? To some other human pedalled spores.
Currently there are nurseries attacking the government for not alerting us to the dangers in 2008, when they were first informed of the latent problem – ash death on the continent. “Why did they not lock down the system then, halt imports and even cross UK trading?” These, however, are the same nurseries, I believe, as have been importing saplings from overseas growers as large scale, centralised production has so undercut the small scale local grower. Don’t I know that story well!
Once again the environment is suffering due to the pressures of modern scale capitalist pressure, financial pressure, corporate pressure. Always brain dead, short-termism whereby money moves ever faster, ever further but to ever diminishing gain and ever increasing damage.
Time to slow down, build up local resources, local provision and, yes, truly local woodlands.