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There is a small hope that unique British races of the species—isolated from continental Europe 8,500 years ago—may prove unusually resistant to the blight.

During the 19th century, as global trade increased exponentially, so did the incidence of tree blights. In the early 20th century, after rich countries instituted biosecurity regimes, the growth rates slowed, and in America, at least until recently, remained fairly linear. But in Europe, around 1960, the infection rate picked up, very likely due to the trade-boosting effect of economic integration. This not only spread diseases around the continent itself. It also made the law-abiding countries of northern Europe, such as Britain, susceptible to the sloppier customs regimes of the continent’s southern fringe.


Dutch elm disease is a tragic thing to watch, but we shouldn’t be too gloomy. Woody vegetation responds, adapts, regroups. What emerges in its recovery stage may not be the same as before, but it will always be a vital, dynamic, arboreal community.

The fungus, now known as Chalara fraxinea, is biologically mysterious, an entirely new organism of uncertain origins. It probably evolved in eastern Asia, where it appears to be harmless to native ash species. Its ancestor is a benign and widespread leaf fungus called Hymeno­scyphus albidus, native even in the UK. But at some recent date, this threw up a mutant, Hymenoscyphus pseudoalbidus, with slight genetic differences but a terrible virulence.

Natural resistance is likely to be the best hope for the survival of a core population of ashes in the UK. Isolated from the continent for nearly 8,000 years, our trees may be more genetically diverse than those in Poland.

For their part, ordinary rural people were mystified by the need for plantations, having lived for thousands of years with woods that renewed themselves spontaneously and indefinitely by seeding, or by regrowth from cut coppice stools and pollards. In place of this system of natural regeneration came the notion of trees as artefacts, biddable machines for the production of timber, programmed at every stage of their lives from planting to cutting.

The fundamental grammar of our relationship with them had been changed. Previously, “growing” had been an intransitive verb in the language of woods. Trees grew, and we, in a kind of subordinate clause, took things from them. In the forest-speak of the Enlightenment, “growing” became a transitive verb. We were the subject and trees the object. We were the cause of their existence in particular places on the earth.

Now, in the extremities of ash dieback, we can see that decades of well-intentioned planting have been not only often unnecessary, but, quite possibly, dangerous. Runtish saplings, often mislabelled and of unknown provenance, are shoved into the ground, regardless of whether they might be vectors for disease, or whether the soil is right and the site appropriate.

The existence of a large population of indigenous ashes is our best safeguard for the future and makes rather baffling the Forestry Commission’s experiment, initiated early in May, of planting out trial plots with 150,000 saplings of “15 different varieties”. The intention is to discover whether a few may be resistant and eventually propagate from them. But as 80 million ashes from probably ten times that number of genotypes are already engaged in just such an experiment across Britain, it is hard to see this as much more than a PR exercise – one that fits tidily in to our long, hubristic belief that the salvation of trees lies with us and our superior arboreal intelligence only.


See also: http://worldwidewood.wordpress.com/2013/06/17/natural-ash-nursery-cleared-and-ready-for-the-deer-fence/

To kick start genomic analyses of the pathogen and host, we took the unconventional step of rapidly generating and releasing genomic sequence data. We released the data through our new ash and ash dieback website, oadb.tsl.ac.uk, which we launched in December 2012. Speed is essential in responses to rapidly appearing and threatening diseases and with this initiative we aim to make it possible for experts from around the world to access the data and analyse it immediately, speeding up the process of discovery. We hope that by providing data as soon as possible we will stimulate crowdsourcing and open community engagement to tackle this devastating pathogen.

We have generated and released Illumina sequence data of both the transcriptome and genome of Chalara and the transcriptome of infected and uninfected ash trees. We took the unusual first step of directly sequencing the “interaction transcriptome” [2] of a lesion dissected from an infected ash twig collected in the field. This enabled us to respond quickly, generating useful information without time-consuming standard laboratory culturing; the shortest route from the wood to the sequencer to the compute

Most importantly, crowdsourcing allows for a new form of potentially effective live peer-review, many sets of eyes interrogating and reviewing data and analyses mean that unusual results are quickly highlighted and can be assessed and dealt with appropriately. Whether they are eventually found to be inconsistencies in analysis or more exciting genuine new discoveries, the end product is brought to the scientific community many times faster than the usual peer-review by a small number of reviewers and crucially it all happens out in the open with maximum transparency. The cornerstone of our crowdsourcing is our repository on GitHub [4], a versioning system designed for collaboration in software development that automatically maintains attribution of contribution, meaning that whoever contributes will get full credit for the difference that they made. We are certain that the data will prove useful to anyone who wishes to be involved in the fightback against ash dieback and that concerted, early data-sharing and open analysis is a crucial step in a productive and timely response to emergent pathogen threats.

Our initiative is an early step towards developing the crucial function of the digital immune system for response to plant pathogens; the thing we cannot upload to a repository is the people with the expertise and the will to contribute, and that is why we need the scientific community to download our data and provide analyses.


The fast-track research funding has been awarded to gather an in-depth understanding of the ash dieback fungus and to provide genetic clues about some ash trees’ natural resistance to attack. Computer models will also be built to develop monitoring plans for the distribution and spread of the fungus, as well as charting how the disease might progress. This knowledge will help to fight the fungus and replace lost trees with those more able to survive.

Professor Sarah Gurr from Biosciences is leading the University of Exeter group in the Nornex consortium that has been awarded the funding. The group includes Prof Murray Grant, Dr Chris Thornton, Dr David Studholme, Professor Gero Steinberg and Professor Nick Talbot. The consortium brings together tree health and forestry specialists with scientists working with state-of-the-art genetic sequencing, biological data and imaging technologies to investigate the molecular and cellular basis of interactions between the fungus and ash trees.

Led by Professor Allan Downie at the John Innes Centre (JIC), the consortium includes: the University of Exeter, The Sainsbury Laboratory, East Malling Research, The Genepool at the University of Edinburgh, The Genome Analysis Centre, the Food and Environment Research Agency, Forest Research, the University of Copenhagen and the Norwegian Forest and Landscape Institute. The research will also complement a project funded by the Natural Environment Research Council (NERC) at Queen Mary University of London to decipher the ash tree’s genetic code.

BBSRC Chief Executive Professor Douglas Kell said: “This agile funding response will ensure we improve our understanding of this devastating tree disease as quickly as possible. Little is known about the fungus, why it is so aggressive, or its interactions with the trees that it attacks. This prevents effective control strategies

According to Kraj, W., Zarek, M. & Kowalski, T. (2012) there are several strains of C. fraxinea in Poland.

As has been widely reported, ash dieback is now established in Lithuania, Latvia, Estonia, Baltic Russia (Kaliningrad), Finland, Sweden, Denmark and Germany, as well as Poland and these are all countries with a Baltic shore. The fungus is also now widespread in southern Norway, just outside the Baltic.

In the south the disease has advanced steadily across central Europe as far as France, Italy, Romania and other countries.

The terrestrial route seems consistent with propagation mainly by airborne spores of the H. pseudoalbidus stage and maps produced in France illustrate this well.  In following the advance of C. fraxinea, it is important to try and discover the first reports in different areas as (a) the fungus spreads very rapidly and (b) once discovered far more people start looking for it. Also it has to be borne in mind that it may have been present for some years before being detected. Because of this and other factors, possible dispersal routes become unclear quickly.

The terrestrial route seems consistent with propagation mainly by airborne spores of the H. pseudoalbidus stage and maps produced in France illustrate this well.  In following the advance of C. fraxinea, it is important to try and discover the first reports in different areas as (a) the fungus spreads very rapidly and (b) once discovered far more people start looking for it. Also it has to be borne in mind that it may have been present for some years before being detected. Because of this and other factors, possible dispersal routes become unclear quickly.

increasingly suggestions are being made that the pathogen has been present in Britain and elsewhere since well before its first report and, if this is correct, at least some nursery stock may have been infected from local woodlands after importation.

So far as the British Isles is concerned, virtually all the current records of Chalara from the wider environment (i.e. not from nurseries or recent plantings) are on the eastern side of the country, many close to the coast. While wind borne spores from mainland Europe may be responsible for many of these outbreaks, most are also near ports, places where there are many arrivals and departures of people and goods to and from other countries. This is particularly apparent in the area around Dover and Folkestone (Forestry Commission, 2012).

A hub for crowdsourcing information and genomic resources for Ash Dieback.

On this website you’ll be able to get data to do your own analyses on ash and ash dieback.
You can see the results of other peoples work as soon as it is available and share your own discoveries in the same way.

You will always get full credit for your work and in doing so contribute to a real community effort.


The green ash and white ash – species from America that are different from the European ash trees found in Britain – appear to be resistant to the Chalara fraxinea fungus which is now threatening more than 80 million trees in this country, research has found.

Scientists believe that it may be possible to create a new type of European ash tree that is resilient to the infection by breeding them with their resistant American counterparts and other species from Asia.

“It might make sense to plant American ash in Britain as a replacement for British ash species, but on the other hand, American ash species are susceptible to the emerald ash borer, a beetle from Asia.”


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