Rising from the ashes

posted on February 19, 2018

Guest blog by Sylva Scholar, Louise Hill

We congratulate Louise Hill on successfully defending her DPhil at the University of Oxford. Louise is the third (and sadly final) Oxford-Sylva scholar. Over the last four years she has been researching the impacts of ash dieback. Here Louise describes in her own words what she has achieved, and what our support has meant to her personally.  Well done Louise!

It’s been a long road to get here, but four and a half years after starting I have finally finished my DPhil. As the Sylva Scholar, I have been extremely privileged to complete my project at the University of Oxford, with opportunities to meet top scientists, speak at international conferences, and produce the best research that I am capable of.

Louise Hill in Wytham Woods. Photo John Cairns

Louise Hill, Sylva scholar, in Wytham Woods. Photo John Cairns

My research project looked at various different aspects of the ash dieback outbreak in Britain. This disease is one of the most important contemporary challenges to the health of our woods and trees. An invasive fungal pathogen (Hymenoscyphus pseudoalbidus) [Ed. formerly known as Chalara fraxinea], it threatens the future of common ash (Fraxinus excelsior) as a dominant tree in Britain. The impacts of this loss will be widespread: over the coming decades we are likely to see significant impacts on the health of woodland and non-woodland ecosystems, on associated biodiversity, and on human health and wellbeing as the benefits of ash trees to society are lost.

My project was broad and investigated impacts in many of these areas.

  • I carried out experimental work to clarify the impacts of ash loss on woodland ground flora and invertebrate communities.
  • I modelled the distributions of trees and their associated traits and functions (with a paper published in Ecology and Evolution: This allowed me to investigate the areas and ecosystem types most vulnerable ash loss, and to develop management guidance to help mitigate this loss (paper in review).
  • In my final year, I investigated the economic impacts, an ambitious project which I am now developing further with collaborators at the Woodland Trust and Fera, and which we hope will produce a high-impact publication with political significance.
Hill et al Ecology&Evolution

Hill et al. (2007) Ecology&Evolution

It’s been a lot of hard work, but I have come away with something I feel really proud of: a project that I could make fully my own, that I believe has contributed to both the scientific understanding of the disease and to practical measures to reduce its harm.

None of this would have been possible without support and input from the Sylva Foundation: the scholarship gave me a fantastic opportunity, and I have tried my best to make the most of it. This experience culminated a couple of weeks ago in an invitation to attend a Plant Health and Biosecurity conference at Highgrove, contributing directly to ideas for future policy.

I hope in the future I can carry on working on research in tree diseases in the future, as this project has given me a real drive to continue in this important area.

Louise Hill

[Note from Ed: Louise Hill’s thesis will soon be available online. We will publish a link as soon as possible.]

More about the Sylva Scholarship

Sadly Louise is our third and final Oxford-Sylva Graduate Scholar, as we have been unsuccessful in fundraising sufficiently to appoint a new student.

Read more stories from our Sylva Scholars

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Chalara ash dieback workshop

posted on March 10, 2017

Grassington Town Hall, Grassington, Yorkshire
Thursday June 8th, 10am – 4pm

Ash dieback workshop

Ash dieback workshop

This free workshop will bring together managers of ash research sites, concerned land-owners and managers of woodlands experiencing or threatened by Chalara ash dieback. The aim is to share information and experience and to renew partnerships in ash genetics and tree improvement research.

Speakers at the workshop will be:

  • Dr Jo Clark (Earth Trust) – The Future Trees Trust ash improvement programme and the Living Ash Project.
  • Ted Wilson (Royal Forestry Society) – The biology of Hymenoscyphus fraxineus.
  • Dr Gabriel Hemery (Sylva Foundation) – Getting people involved! The AshTag citizen science project.
  • Ted Wilson (Royal Forestry Society) – Silviculture and management of ash – best practice advice for woodland managers.

After lunch, we will visit Grass Woods, a mature woodland owned by the Yorkshire Wildlife Trust which has been badly affected by Chalara ash dieback.
Numbers are limited, so to reserve your place at this important event, contact Tim Rowland at Future Trees Trust on 07896 834518 or e-mail him at

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Have you tagged your ash trees yet?

posted on July 2, 2014
Living Ash Project website

Living Ash Project website

Sylva is asking for help in adding ash trees to an important nationwide survey. We want volunteers to ‘tag’ trees and complete a simple survey online.

We still have a few tags available to give away free, on a first-come, first-served basis. If you would like to receive a pack of five tree tags for free please:

register your interest here

We are asking members of the public to get involved by tagging up to five ash trees that will be surveyed once every year. Tag packs consisting of five tags have been developed, each with a unique identification number, plus aluminium nails to affix it to the tree stem (these do not harm the tree), together with full instructions. Once that the trees are tagged, we ask volunteers to complete a simple annual survey about its health. The survey is hosted by our partner Ashtag and is available online on computer, tablet or smartphone. Volunteers are asked to pinpoint the tree location(s) on an online map, take a photograph, then answer five straightforward questions.

As Chalara ash dieback spreads across the British Isles, the Living Ash Project aims to identify and secure ash trees that show good tolerance to the fungus that causes the dieback (Hymenoscyphus pseudoalbidus) and use these individual trees as the foundation of a breeding programme.

Partners in the Living Ash Project will be assessing the many thousands of trees that exist already in a breeding programme for ash, and we will use citizen science to screen the wider population – and this is where your help is needed. Later, we will produce trees that show good tolerance to the fungus, and plant them on the public forest estate as an archive, freely available to the forest industry. We will also develop techniques to enable us to rapidly produce large numbers of tolerant trees for reforestation. The five year project is funded by Defra.

Read more about the Living Ash Project

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Public asked to help survey health of ash trees across UK

posted on April 22, 2014

The Living Ash Project is asking members of the public to report information about the health of ash trees. They are especially interested in those that may have some tolerance to the disease that is threatening Britain’s second-most common broadleaved tree – Chalara ash dieback.  The Living Ash Project aims to identify trees that are tolerant to ash dieback.

Launching today, anyone can log into an online survey, and report on the health of an ash tree, not just this year, but over the next few years. The project is employing citizen science – asking members of the public to help in gathering information – to aid in the identification of tolerant trees.  Working with the University of East Anglia’s Adapt Group, a new function has been added to the AshTag app. Members of the public can log into the site at

There are an estimated 120 million ash trees in Britain’s woodlands and hedgerows. Evidence from Denmark, where Chalara ash dieback is more prevalent, indicates that approximately 1% of trees show good tolerance to the disease. While tolerant trees may regenerate naturally in some woodlands, identifying tolerant trees is urgently needed so as to ensure a genetically diverse and resilient population for future woodland planting. Identifying tolerant trees and including their progeny in breeding programmes run by the Living Ash Project will enable the large-scale production of resilient trees.

Gabriel Hemery, Chief Executive at the Sylva Foundation says: “The launch of this survey is a milestone in the development of the project. We will be working closely with AshTag to oversee the online survey and look forward to receiving submissions from members of the public”. He added, “Enabling people to follow the progress of an ash tree is very important, as it will allow us to understand the tolerance of a tree to this devastating disease”.

Chris Blincoe, Programme Manager at the Adapt Group, University of East Anglia says: “The AshTag app was created at a time when the nation’s ash trees were first under threat from ash dieback and the outlook for the species was pretty bleak. Time really was of the essence if we wanted to safeguard our forests and so Adapt had the app up and running just four days after it was confirmed that ash dieback had spread to the UK. Eighteen months on, we are incredibly proud to be in a position to start looking ahead to find a solution to the disease.”

“By asking members of the public across the UK to track the health of their local ash trees, we can tap into a wealth of data which could hold the key to locating tolerant trees and safeguard the future of the UK’s ash trees.”

The Living Ash Project team are most interested in larger trees but any tree can be surveyed. They are particularly keen to survey ash trees in every corner of Britain, because the genetics of ash trees vary across the country. Ideally, the trees selected need to be surveyed every year for at least three years, so that a detailed picture of their health is built up.

People who want to find out more can visit to take the survey and to get free tags to track the health of their tree.

download press release

download press release

Download the full press release

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Calling woodland owners – help wanted in ash dieback research

posted on March 13, 2014

Sylva Scholar Louise Hill – who is studying the consequences of Chalara ash dieback in British woodlands (read more) – is looking for woodland sites in the south of Britain where she could set up her experiments. If you are a woodland owner, perhaps you could help her?

Louise Hill, Sylva Scholar

Louise Hill, Sylva Scholar

Louise explains:

I am looking for areas of deciduous woods, with ash mixed in to it ideally at a density of around 300 stems/ha (i.e., not an ash monoculture). Within each site I want to set up at least one (ideally two or three) blocks of plots; each block will contain three plots of 25 x 25m, one of which will have 100% of the ash ring-barked, one 50% and on 0% (control). The experiment will look into the effects of loss of ash trees on growth rates of the remaining trees, recruitment of seedlings of other species (ash seedlings will be removed), and also effects on the ground flora. It will also look into any interactions with deer abundance for these effects. I am looking for sites in Oxfordshire, Dorset, Hampshire and the Isle of Wight.

If you have a suitable site, and are prepared to have some ash trees sacrificed in this way, please contact Louise directly to discuss further. She can be reached at

Read more about the Sylva Scholarship



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Living Ash Project – securing the future for ash trees in Britain

posted on November 13, 2013
Living Ash Project

Living Ash Project

Today sees the launch of the Living Ash Project – a Defra-funded consortium of Earth Trust, Future Trees Trust, Sylva Foundation and Forest Research – aiming to identify ash trees with good tolerance to Chalara ash die-back, to sample these trees for further breeding work, and to make this material quickly available to industry.

There are an estimated 120 million ash trees in Britain’s woodlands and hedgerows. Evidence from Denmark, where Chalara ash die-back is more prevalent, indicates that approximately 1% of trees show good resistance to the disease.

While natural selection in some woodlands could enable resistant regeneration, the identification of resistant trees is needed as the basis for a genetically diverse and resilient population for future productive woodland planting.  Quickly identifying resistant trees and using them in a breeding programme will enable us to rapidly produce resilient trees.

The Living Ash Project aims to secure ash trees for the future that show resistance to Chalara ash die-back. It is important that a good proportion of trees that make it through a screening programme will be suitable for timber production to ensure a continued supply of this valuable product for the future. The project partners have been working on breeding ash for improved timber characteristics for over twenty years and in this time have assembled a substantial collection of ash trees from across ash’s native range which has great genetic diversity.

Sylva’s CEO Dr Gabriel Hemery said:

“Sylva’s main role in the project will be to work with members of the public, including woodland owners, who we want to report the presence of healthy trees.” He continued, “We will be announcing details soon about a national ash tree survey, which we hope people across Britain will get involved in: after-all, the future of our ash rests in all our hands.”

The Living Ash Project incorporates work programmes to:-

i)                   identify individual trees that show good tolerance of Chalara ash die-back

ii)                  screen these individuals using genetic markers developed by other Defra funded research

iii)                secure material from these trees in archives for further breeding purposes

iv)                develop techniques for rapid production of tolerant trees for deployment to the forestry sector


Project leader Dr Jo Clark from Earth Trust said:

“This is a great example of charities and government agencies such as Forest Research working together to address what is probably the biggest issue facing our woodlands today. Earth Trust, Sylva Foundation and Future Trees Trust together have dozens of partners and supporters across the forestry sector, all of whom will be getting involved in the awareness, screening and identification work.”

Defra’s Chief Plant Health Officer Martin Ward said:

““We know we can’t eradicate Chalara but the Living Ash project offers  a real solution in dealing with the disease.  Britain’s woodlands are constantly evolving but projects like this one will ensure that ash trees have a place in the woodlands of the future.”

In total, including in-kind contributions from the many partners, the project will cost approximately £1.2M and will take six years to complete.

Information can be found on the project website 

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Ash dieback discovered in Dorset

posted on August 22, 2013
close up of Chalara fraxinea lesion on young ash coppice stem

close up of Chalara fraxinea lesion on young ash coppice stem

In the week that AshTag relaunched to enable citizens to report both healthy and diseased ash trees Chalara fraxinea or ash dieback, was discovered in a thirteenth county in England. The latest county, Dorset, joins Cambridgeshire, Devon, East Sussex, Essex, Kent, Lincolnshire, Norfolk, Northumberland, Suffolk, Surrey, West Sussex and Yorkshire.

According to Defra the disease has now been confirmed in 557 sites including 198 locations in the wider environment. Chalara was discovered in England’s woodland last Autumn as a result of the intensive survey carried out of sites across the UK where ash trees are known to be present. It is also found in sites across Northern Ireland, Scotland and Wales, although most of these currently are on sites planted (unknowingly) with diseased trees in recent years.

On a recent Good Woods visit to a woodland in south east England, a new case was discovered by one of our advisors. It had previously gone unnoticed by the owner, and only came to light during the visit as a management advice was being drawn up.

Further information

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Chalara – advice to forest visitors

posted on November 13, 2012
Ash dieback Chalara fraxinea woodland posters

Download the ash dieback Chalara fraxinea posters from the Forestry Commission website

Following on from our recent advice to woodland owners relating to Chalara fraxinea, we wish to make woodland owners aware of some clear posters designed by the Forestry Commission targeted at forest visitors.

Two versions have been designed; one for owners with trees infected with Chalara fraxinea, the other for those with healthy trees.

To download the posters click on the images.


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Chalara fraxinea – advice for woodland owners

posted on November 8, 2012

The outbreak of Chalara fraxinea in the British countryside is very major story that cannot have escaped anyone’s notice. Infected sites currently total 115, distributed from SE England, East Anglia and the Midlands, to Scotland, to Wales.

Through the myForest Service, Sylva supports currently some 700 woodland owners who manage about 15,000 hectares of woodlands across Britain. We encourage all woodland owners to keep abreast of a very fluid situation in terms of current status of the outbreak and advice from Government and scientists and how we should all respond. The best place to keep informed is via the Forestry Commission webpage: Meanwhile, Sylva offers the following advice to woodland owners:

  1. Inspect ash trees in your woodland without delay. Before the winter winds remove all leaves, those infected by Chalara can be quite obvious in that they persist after those that drop as usual in the Autumn (see image). On young trees, coppice regrowth or other regeneration the lesions can be quite easy to spot. On older wood they are less clear. Dieback in the canopy may be possible to spot during the dormant season but it is easy to miss.
  2. If you believe that you have Chalara fraxinea in your woodland contact the Forestry Commission without delay.  The Forestry Commission are treating C. fraxinea as a ‘quarantine’ plant pathogen, which means that they may use emergency powers to contain or eradicate it when it is found. This is being done in the form of Statutory Plant Health Notices which they serve on affected owners requiring them to remove and destroy affected plants by burning or deep burial on site. This situation may change in time.
  3. Where possible implement rigorous biosecurity measures. Follow the advice of the Forestry Commission’s Biosecurity Measures.
  4. In terms of minimising the impact of the pathogen on ash trees within an infected woodland, current thinking is that the removal and burning of ash leaf litter may reduce the prevalence of the pathogen next year. This may be a practical action in high value sites, such as important biodiversity areas, parklands, garden trees or perhaps notable ancient trees. In larger ash stands clearly this may not be practicable.
  5. Felling of diseased trees. Advice is not yet clear on this issue. Note that finding resistant trees in the ‘wild’ will be very important in creating the foundation for a new population of trees resistant to the pathogen. Felling all ash trees in infected woodlands therefore, cannot be recommended.
  6. Before transporting ash wood, check the Forestry Commission webpage for the latest advice.

Over the coming weeks the Government’s taskforce will be bringing together experts to build up a picture of the current status and the appropriate measures that we should be taking to try and reduce the impact of this devastating pathogen. Our Chief Executive, Dr Gabriel Hemery, is taking an active role in the taskforce and we will be providing up-to-date information here when available.

Photographs taken by Gabriel Hemery during the expert taskforce
visit to Wayland Wood in Norfolk earlier this week.

Further information

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Chalara dieback of ash (Chalara fraxinea)

posted on October 28, 2012

Chalara dieback of ash is a serious disease of ash trees caused by a fungus called Chalara fraxinea (C. fraxinea).  The disease causes leaf loss and crown dieback in affected trees, and it can lead to tree death.

There has been significant media coverage about the arrival of this fungal pathogen in the UK over the last week and with good reason. It is potentially very destructive to our native Ash, as can be seen by looking at our European neighbours e.g. Denmark and Germany.

For further information please follow the link to the Forestry Commission website below. We will aim to update this blog post with relevant information for woodland owners and forest managers as it becomes available.

Forestry Commission – Chalara dieback of ash


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