Oak disease ‘threatens British landscape’

The continuing spread of a deadly disease that affects the UK’s native oak trees is causing concern among tree professionals and conservation groups.

Take Cover library photoThe BBC’s environment reporter Mark Kinver writes that Acute Oak Decline (AOD), caused by a bacterial infection, can kill an infected tree in just a few years.

Some tree experts are comparing AOD to Dutch elm disease, which killed millions of trees throughout the UK during the 1970-80s.

They said extra funds for more research into the disease were urgently needed.

Although AOD has been confirmed in 55 cases, the number of trees displaying symptoms was steadily increasing, delegates at the Royal Forestry Society’s (RFS) annual conference were told.

The disease affects the UK’s two native species of oak – sessile and pedunculate. To date, there have been no confirmed cases in other species of oaks found in Britain, such as Turkey and red oaks.

‘Extensive bleeding’

Information from Forest Research, the scientific department of the UK Forestry Commission, says the new disease affects oaks more than 50 years old.

Symptoms are “extensive stem bleeding” in which dark fluid seeps from small cracks in the bark and runs down the tree trunk.

In early stages of the disease, the health of a tree’s canopy does not appear to be affected, but it may become thinner as the tree succumbs to AOD.

On its website, Forest Research says: “The incidence of AOD in Britain is unquantified at this stage, but estimates put the figure at a few thousand affected trees.

“The condition appears to be most prevalent in the Midlands and investigations to determine the extent of the disorder are under way.”

A spokesman told BBC News: “Forest Research pathologists have isolated a previously unidentified bacterium they believe is highly likely to be playing a key role in the Acute Oak Decline observed in Leicestershire and elsewhere.

“However, the full cause of the condition is thought likely to be complex, involving a number of factors besides the bacterium. A research report is currently awaiting peer review.”

‘Major threat’

Tree organisations are calling for more funding to be made available to allow researchers to better understand the full impact of the disease.

John Jackson, the organiser of the RFS’s conference, said: “Urgent action is not an option – it’s a necessity.”

Hilary Allison, policy director for the Woodland Trust, added: “The impact of the loss of an iconic tree both from our countryside and towns would be catastrophic, and therefore has the capacity to be a major threat to the UK’s oak woods.”

“I have never seen anything like it,” said Peter Goodwin, co-founder of Woodland Heritage.

“Its spread over the last two years has been quite alarming.”

Mr Goodwin told BBC News that very little was known about the virulent bacteria responsible for the disease.

“We’ve never had a bacterium that is capable of doing what this one is doing.”

He suggested that people were possibly the main way in which the disease was spread from tree to tree, but added that “natural vectors” – such as squirrels, birds and insects – could also play a role.

“I think this is the worrying thing, we all want to know what are the vectors that is spreading it. Is it airborne? We just don’t know.”

Forest Research advises people working in affected areas to take appropriate measures to limit the chances of AOD being carried to new sites.

“The most important thing we can do in this and other cases is to research and understand the causes so that we can provide appropriate management advice for tree owners and woodland managers,” the spokesman added.

“It is also important that we remain vigilant against accidentally importing new and damaging pests and diseases from outside Great Britain.”

Source: BBC News website

Date: 28/04/10

Forest Research draws up canker plan

Forest Research is to develop guidance on managing and drawing up controlling strategies for the bleeding canker tree blight, reports Horticulture Week.

“This disease has rapidly become widespread throughout Britain over the past five years,” said a representative for the research arm of the Forestry Commission.

Bleeding canker of horse chestnut was caused by the bacterium Pseudomonas syringae pv aesculi (Psa), but until recently it had only been reported in India in 1980, he said.

“It has now proved to be highly mobile and exceptionally virulent to European horse chestnut, Aesculus hippocastanum.”

Researchers were looking to provide an accurate diagnosis of the pathogen and underpin management strategies to combat the disease.

“A technique called real-time polymerase chain reaction has been developed and is being used to detect the levels of Psa on infected trees and their surroundings.”

Previously little was known about what natural resistance horse chestnut populations may have had to Psa.

“But evidence indicates that even in heavily affected locations some trees remain healthy and symptom-free.

“Disease-free horse chestnuts have been propagated and will be tested for disease resistance in inoculation trials and compared against other disease-prone individuals.

“This research will ultimately guide management and mitigation strategies. Molecular techniques developed will also be applicable to the study of other important tree diseases.”

Source: Horticulture Week

Date: 07/05/2009

UK forest agency launches greener towns partnership

Making Britain’s towns and cities greener places to live and work is the aim of a new partnership being launched by the UK Forestry Commission on 25 March, 2009.

The Urban Regeneration & Greenspace Partnership (URGP) will be officially launched at the ParkCity conference in London.

It will work to bring together a range of government departments and agencies, local authorities and community and environmental groups to work in partnership to create, manage and promote sustainable green spaces in towns and cities.

“Urban greenspace” is a term used to describe natural habitats – from street trees to open grassland, heathlands and woodland – in and around towns and cities.

Greenspace provides a wide range of social, economic, health and environmental benefits, including the creation of wildlife habitats, noise reduction, sustainable drainage and flood control, cooling of buildings and the built environment, improved air quality, and opportunities for sport and recreation.

The URGP will aim to:

  • demonstrate the value and awareness of the impacts and outcomes of greenspace in and around towns and cities;
  • disseminate best practice and case studies;
  • enable innovation and knowledge transfer;
  • provide a network of research and evaluation sites;
  • identify gaps in knowledge and priorities for research and dissemination; and
  • provide a link to research services across the UK.

Tony Hutchings from the Forestry Commission’s Forest Research agency, based at Alice Holt Lodge near Farnham in Surrey, is the co-ordinator of the URGP.

He said: “The use of greenspace in towns and cities is increasingly being seen as having a vital role to play in helping to regenerate them.

“This can involve, for example, transforming a neglected area of derelict ground into a park where people can meet, walk, talk and play.

“The URGP will play a vital role in raising the awareness, impacts and outcomes of urban greenspace.

“We look forward to working with a range of parties from all sectors to establish more urban greenspace and realise the benefits it offers.”

Organisations interested in joining the URGP or being kept in touch with its work and development are invited to contact the partnership.

Further information about the Forestry Commission’s work on urban regeneration and land reclamation is available from the Forest Research website.

Source: Forestry Commission press release

Date: 19/03/2009

UK’s famous maples ‘must adapt to climate change’

The collection of Japanese maples at the UK National Arboretum need to adapt in order to survive the impacts of future climate change, a researcher has told a conference examining the problem.

Speaking at PlantNetwork’s “Climate Change and Planting for the Future” gathering, Dr Richard Jinks of Forest Research outlined how the UK Forestry Commission was embarking on a full-scale plan to ensure that the world-famous collection of Japanese maples at Westonbirt, Gloucestershire, could thrive in the future.

A press release from the Forestry Commission explained that an evaluation of these and other trees in the collection would assess their drought tolerance and the best way of helping them adapt to change.

Measures are likely to include succession planting and good horticultural practices to enhance soil moisture levels in dry summers.

There are more than 300 types of maples (acers) in the National Japanese Acer Collection at the National Arboretum.

Each autumn they put on a blazing show of colour, admired by many thousands of visitors from all over the world.

Dr Jinks said many acers thrived on a constant supply of moisture, and the evaluation would highlight how the trees could be susceptible to extended periods of drought.

“These acers are not only stunning trees but also form an important national collection,” he told delegates.

“It is vital that we take stock now and monitor them closely, putting plans in place to safeguard their future.

“We need to propagate and plant new collections now, not only for 50 years time but for far into the future.”

The PlantNetwork conference attracted more than 100 delegates from botanic and historic gardens, government agencies and research institutes.

It was held at the Royal Agricultural College, Cirencester from 10-12 September.

Source: Forestry Commission press release

Date: 11/09/2008

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