c National


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.

http://www.economist.com/news/britain/21580459-arboreal-confirmation-britain-european-country-european-problems-unquiet-woods?fsrc=rss|btn

By far the most interesting part of the discussion, and perhaps the more optimistic, was identifying how we might rise to the challenge of making our precious trees and woods more resilient in the face of these on going and inevitable threats. With the input of renowned woodland ecologist, Keith Kirby from University of Oxford, the group considered how the natural and cultural history of our woods has shaped them – and what we can do to give nature a helping hand.

This cannot be a ‘one size fits all’ approach and there is no simple template that all woodland owners and managers should follow – in fact the tendency to try and manage all of our woods in the same way in the past or previous suddenly shifts in management resulting from pursuit of narrow theories has probably made them more vulnerable today. A vulnerability compounded by the continuing gradual loss of woodland and the fragmentation of woods and other habitats, leaving them disconnected and isolated.

But some key principles are emerging. Our woods will be more resilient if they contain a wider range of native species, and have a more diverse structure too – so that we have a good mix of types of trees and a range of young, established and older trees.

Prof Erik Kjaer from the University of Copenhagen, confirmed that a small proportion (around 2%) of ash may be naturally resistant or tolerant to chalara. There are also good signs that this characteristic can be passed on to progeny of those surviving trees.

http://wtcampaigns.wordpress.com/2013/06/28/making-our-woods-more-resilient-tapping-in-to-the-insight-of-experts/

See what we are doing: The Natural Ash Nursery –

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

The scientists are extremely hopeful that, having determined the tree’s complete set of genetic material – through a process known as genome sequencing – they have paved the way to identify those genes which might be connected to its ability to withstand the fungus.

Although the breakthroughs have raised hopes that a new breed of ash will be able to grow and survive in the face of the fungus, they will do nothing to protect Britain’s 80m existing ash trees, which are all under threat.

Adult clones of tree 35 grown from cuttings taken from the original trees in the 1930s were recently discovered on the Danish island of Sealand. [However] just planting this variety of Ash in the UK would result in a narrow genetic base making the species vulnerable to future diseases, experts said, adding that the latest breakthroughs still represented a giant step forward for the long-term prospects of the tree in this country.

http://www.independent.co.uk/news/uk/home-news/genetic-secrets-of-resistant-tree-gives-new-hope-over-ash-dieback-disease-8660992.html

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.

http://www.newstatesman.com/sci-tech/2013/06/our-ash-trees-are-dying-dont-despair-catastrophes-are-natural-events-lives-trees

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

The South East has been declared a “low priority” area – authorities say that because the disease is already widespread, it is not cost effective to tackle it.

Dr Alun Griffiths, microbiologist and chairman of the Kent Men of the Trees conservation charity, said the county needed better protection.

“I’ve been studying diseases around the world all my professional life,” he said.

“I’ve always thought that if you have a focus, an area where disease is being spread rapidly, that would be the place where you’d put most of your effort.

The government is planting thousands of young ash trees in the region as part of a research trial, including at the Hucking Estate near Maidstone.

Scientists hope 1% of them may survive and develop resistance in a decade’s time.

http://www.bbc.co.uk/news/uk-england-kent-22510873

 

Genetic resistance to ash dieback disease is to be studied at a Suffolk Wildlife Trust (SWT) nature reserve.

Scientists from the Forestry Commission are using the site at Arger Fen and Spouse’s Grove, near Sudbury, to study genetic resistance to the Chalara fungus – which causes the disease.

About 15 different strains of ash will be planted on the five acre site later this week.

The trust responded to a request from the Forestry Commission for sites.

http://www.bbc.co.uk/news/uk-england-suffolk-22484952

I am particularly excited that the Real Life Science Studio in the John Hope Gateway will be hosting the Virtual Landscape Theatre for one week from 8th August. This interactive exhibit allows an audience to decide what actions should be taken to reduce the impact of ash dieback and to explore the implications of these choices. Intrigued? Come and find out more in August!

Diseases are a real threat to our trees and it is likely we will loose a high proportion of our ash trees. Yet, over the course of this project I started to feel more positive about the future of Scottish woodlands. It would be easy to listen to the mass media and get very depressed about the state of our forests and trees. But woodlands are dynamic and have always changed; over such long periods of time we humans find it difficult to comprehend.

We need to build resilience in the woodlands of Scotland to ensure their longevity. By this I mean managing woodlands in a way that creates diversity in the species present, diversity in the age of the trees and diversity in structure. If we do this it may be possible to maintain the ever-changing, unique woodlands of Scotland.

http://stories.rbge.org.uk/archives/2051

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