March 2013


The implications for lichens of the spread of Chalara Dieback of Ash, a disease of ash trees caused by the fungus Chalara fraxinea, could be very serious.

The light dappled shade beneath its canopy is ideal for many of the lichens that grow on tree bark and wood. Like elm, the bark of ash has a relatively high pH, a requirement for many lichens.

http://www.britishlichensociety.org.uk/about-lichens/habitats-conservation/ash-chalara-dieback-and-lichens

The majority of forest volume in the UK is not publicly owned – out of a total forest area of 3 million hectares in the UK, only 28% is managed by the Forestry Commission. For ash, this figure is much lower, with only 3% of ash woodlands not owned by the private sector.

For private owners, the costs of surveying, felling, and replacing ash trees are likely to be high, and the effects of this could be long-lasting. An increase in the amount of timber in the market could also drive prices down, affecting landowners even further.

For landowners to engage in monitoring ash dieback, resources must also be available for them to do so. The number of inquiries sent to the Forestry Commission’s Tree Health Diagnostic and Advisory Service has increased by 1000% over the past six months. As diseased trees come into leaf over spring, and more trees become infected when the Chalara fungus sporulates again in summer, this high workload could even increase.

The number of tree diseases present in the UK has risen exponentially over the past 20 years, and now, almost all tree species are under threat from at least one disease or pest. Red band needle blight and ash dieback threaten up to 18% of woodland in the UK.

The report compiled by Confor highlights that the extent of private ownership of ash woodlands needs to be taken in to account.

http://britishecologicalsociety.org/blog/blog/2013/03/15/assessing-the-impacts-of-ash-dieback/?utm_source=twitterfeed&utm_medium=twitter&utm_campaign=Feed%3A+EcologicalAndPolicyBlog+%28BES+Ecology+%26+Policy+Blog%29

Should we start planting Ash with natural Chalara resistance even if they aren’t of UK provenance, e.g. Danish ‘Tree 35′?

AD: We should be very clear that tree 35 is not ‘resistant’. It tolerates the fungus better than most but it still gets infected. We do not know what is likely to happen with such trees over 20-40 years. The plan it to see if there are different genetic determinants in different trees that tolerate the fungus. If there are, it may be possible to cross them with each other and combine the characters to increase tolerance.

DM: It isn’t certain whether ‘Tree 35′ is going to be tolerant against the UK population of ash dieback. Tree 35 has shown to have great tolerance, but it isn’t clear how it will be in 20 – 30 years and we want to be able to create long term resistance. That said, there are great lessons to be learned from the genetic makeup of this tree and understanding how it has reached this tolerance is going to be of great benefit. In the end we would like to achieve a UK population of resistant trees, with UK-specific diversity, as our tree population is genetically different from the Danish population.

JW: Before we can go ahead with widespread planting of ash trees such as Tree 35, we have to be sure about the extent of its resistance.  However, just because trees/seeds are not of UK provenance doesn’t mean we should exclude them.  The releases from a number of programmes breeding for resistance to Dutch elm disease have made use of a wide range of elm species from Asia to produce resistant elms.  Also, many of the broadleaf trees planted in Britain, including oaks raised after the Napoleonic wars, have depended on seed from other European countries.

http://oadb.tsl.ac.uk/?p=371

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

In a normal year, the service receives a combined total of 750 enquires. But in autumn 2012, the UK saw multiple cases of chalara, a serious disease of ash trees which is caused by the fungus Chalara fraxinea.

Since then, THDAS has received over 4000 enquiries from England and Wales alone (as well as approximately 200 from Scotland), a workload ten times higher than normal.

That massively increased workload comes as the service struggles with budget cuts introduced in the years leading up to the 2010 election.

http://www.newstatesman.com/politics/2013/02/biosecurity-agency-cut-labour-experiences-1000-cent-increase-workload

Ancient woodlands covering an area larger than 12,700 football pitches are threatened with destruction to make way for new building developments and the controversial high-speed rail link.

Analysis by the Woodland Trust has revealed that at least 350 woods, which have all been a feature of the landscape for more than 400 years, could be lost or permanently damaged under plans to build housing, roads, quarries and the £33 billion rail route.

The scale of the threat, which the group says is the greatest in the 15 years since ­it began recording ancient woodlands at risk,

http://www.telegraph.co.uk/earth/greenpolitics/planning/9919768/Our-ancient-woodlands-that-could-be-lost-to-the-bulldozer.html

Forestry officials have confirmed the Chalara fraxinea fungus, which causes ash trees to gradually wither and die, has been found at three new sites in young trees in Wales.

The cases are the first to be identified since the start of the winter, as the symptoms of the disease, which threatens to devastate Britain’s 80 million ash trees, become hard to spot in trees once they lose their leaves.

The number of cases to be found in Britain stands at 386 since it was first discovered last February, with 170 of these in mature established woodland.

All the trees at the three sites, which had been supplied by a nursery previously found to be infected with the fungus, were destroyed. Testing has suggested around 10 per cent of ash tree sites are infected.

Scientists have also found that infected trees were being imported into Britain from elsewhere in Europe as early as 2008 – far earlier than believed previously.

“In the case of Chalara, it’s very important to make sure you don’t inadvertently move ash leaves, living or dead, around the countryside.”

http://www.telegraph.co.uk/earth/environment/9904591/Ash-dieback-found-in-three-new-sites-in-first-infections-of-the-year.html

 

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