Deadly oak disease hits Welsh private woodland


An outbreak of the pathogen Phytophthora ramorum, otherwise known as sudden oak death, has been discovered for the first time in Wales on trees in a privately-owned woodland, reports the Forestry Commission Wales.

Staff from Forestry Commission Wales and the Food & Environment Research Agency (Fera) have visited the owner of the woodland in Denbighshire and a notice has been served to fell the infected Japanese larch trees. Only a small number of trees are infected, and the owner will use the timber on site.

Sudden oak death is a fungus pathogen that kills many of the trees that it infects. It was first found on Japanese larch trees in Wales in June this year in public woodlands  near Port Talbot, near Bridgend.

The outbreak in South Wales was the first time P. ramorum has been encountered on larch elsewhere in Great Britain since it was first discovered on larch in South-West England in 2009.

The woodland owner, Wendy Charles-Warner, contacted Take Cover, to say: “We feel rather aggrieved at the tone of the [Forestry Commission] press releases stating that we have been served with enforcement notices as if we were responsible for this outbreak and somehow in the wrong.

“We could take no steps to prevent this disease which is mainly airborne, have done nothing wrong and have at every point done everything we can to assist the forestry commission.”

A motor rally set to attract thousands of spectators to South Wales in July was postponed as a result of an ou6tbreak of the tree disease.

The route of the Swansea Bay Rally ran through forests that had been hit by the infection.

Richard Siddons from the Forestry Commission Wales said the organisation was “determined to minimise the impacts of this serious tree disease on woodlands, and the support of woodland owners in looking out for early signs of P. ramorum infection will play a key part in achieving that”.

It seems as if the warm but wet summer has been a key driver in the development of tree pathogens, with a number of cases making the headlines.

In April, a group of woodland experts expressed their fears for the future of British native oaks in light of the emergence of a disease called Acute Oak Decline, a bacterial infection that, they warned, could be as devastating for the English Landscape as Dutch elm disease in the 1970s.

They called for much more financial support from the UK government to help tackle the problem through research and land management measures.

In July, the Forestry Commission announced a £600,000 support package for woodland owners in South-West England and Wales to help tackle the outbreak of P. ramorum infection on larch trees. The package is part of Defra’s £25 million, five-year Phytophthora management programme.

Forestry Commission Wales is developing a complementary programme of support for private woodland owners who have P. ramorum confirmed on their land. Details of this support will be announced in September.

Ms Charles-Warner, in her comment to the story on this blog (see below for her full response), added: “

The ‘package of assistance’ that the Commission have announced is £300 per hectare, which we are not receiving or going to receive.

“If you have knowledge of tree felling you will appreciate that in a situation where stringent biosecurity measures have to be used and the trees have to be felled and brashed by hand that is a paltry sum, even in the highly unlikely event that you receive it.

She went on to say that she was “deeply concerned” about the situation: “If the Commission wishes landowners to report Phytopthora Ramorum and control it, in order to protect commercial forestry, then realistic support needs to be in place.

“Many landowners faced with a the prospect of funding felling and site clearance work themselves with the attendant stress and unpleasantness, are likely to ignore the disease and not report it.”

More information about sudden oak death can be found on the Forestry Commission’s website at www.forestry.gov.uk/pramorum.

To find out more about the support fund or to report suspected P. ramorum infection in their trees, woodland owners should contact Forestry Commission Wales’s Grants & Regulations Office on tel: 0300 068 0300 or email: bww.ts@forestry.gsi.gov.uk.

Source: Forestry Commission Wales press release

Date: 25/08/2010

British public ‘ignorant about trees’


According to a survey reported in Horticulture Week, a trade magazine, more than three-quarters of the people questioned believed that the main role of trees was to provide shade.

The questions, posed on behalf of Velvet Tissues – a UK-based toilet paper firm – also had a few more positive messages when it came to people’s attitudes towards trees, such as 75% agreed that trees featured in a favourite memory and 9% remember kissing a childhood sweetheart under a tree.

More than two-thirds of the people questioned considered the oak to be the UK’s most iconic tree, yet – depressingly – a third were not able to identify it.

The survey is hardly scientific,  and it is surely closely tied to a PR campaign in which the company describes itself as a tree lover (its website says it plants three trees for every one it cuts down to make its products), we felt it was worth featuring on this blog.

Sadly, it was not possible to get more details on the survey’s background because there is nothing on the company’s website and Horticulture Week only ran a very short story on the findings.

Source: Horticulture Week

Date: 25/08/2010

UK elms – ‘not out of the woods yet’


Colin Tudge, the author of The Secret Life of Trees, is invited by the UK’s Telegraph newspaper to give his reaction to efforts to breed a Dutch elm disease-resistant species.

Library image from Take CoverIt’s an interesting read as he gives his reaction to this battle with nature, so here it is:

Could the English elm, so sadly laid low by Dutch elm disease, make a comeback? Paul King, who breeds trees at Raine in Essex, is on the case. Nearly 25 years ago he acquired cuttings from a few mature trees. He has now multiplied the tissues to produce a whole new generation of young elms that seem to be resistant (and are on sale for £120 apiece). Scientists at the Forestry Commission’s research centre in Surrey welcome his initiative – they are on the case, too – but are cautious. Resistance, they point out, is a tricky business.

The English elm, Ulmus procera, is probably not a “true” native – Britain has only 39 “truly” native trees – and was most likely introduced by Neolithic farmers from south-east Europe, via Spain. But it is an honorary citizen, treasured for its usefulness and its looks, favourite of landscape painters, notably of Constable; a tree of open woodland but just as happy in hedgerows where, if it was left alone, it flourished by the tens of millions. In the West Country it was known as “the Wiltshire weed”.

The first sign of trouble came in 1910 when the fungus Ophiostoma ulmi, a distant and degenerate cousin of the truffle, started killing trees in mainland Europe. It acquired its name, Dutch elm disease, in 1921 because it was first properly researched in Holland. It arrived in Britain by 1927 and looked very nasty. Happily, the disease died down by the Forties, after killing 10 to 40 per cent of our elms. Dr Tom Pearce of the Forestry Commission predicted, in 1960, that such a thing should not happen again – unless, he added, “the fungus completely changes its present trend of behaviour”.

Which it duly did. A new, closely related species of Ophiostoma appeared in North America – Ophiostoma novo-ulmi. It arrived in Britain in 1967 on imported logs, and throughout the Seventies and into the Eighties it killed about 25 million out of about 30 million elms, including most of the particular English species, Ulmus procera.

Dutch elm disease has all the biological attributes needed to be thoroughly nasty. It is one of the many “wilt diseases” of trees, which spread through the vessels of the xylem and block them. The spores are carried passively with wonderful efficiency in the sap, through the whole tree, and spread via the roots of separate trees that are often joined underground. The spores don’t live long once the tree has died and so should die out as their host succumbs – but they have a trump card: they are carried from tree to tree and from forest to forest by flying bark beetles of the genus Scolytus.

There is some innate resistance among the world’s many species of elm. The Ophiostoma fungus probably arose in Asia, so the Asian elms have evolved in its presence – and have developed considerable resistance. Breeding programmes are afoot in Europe to introduce genes from Asian species into European types by various means – and may yet succeed. Meanwhile, as Paul King has found, even within susceptible species, such as Ulmus procera, there will usually be some resistant strains. If they can be bred, perhaps we will have a new resistant strain.

So why the caution? Well, for one thing, it depends what the tree is really resistant to: the fungus or its insect vector? Paul King’s new trees are probably not resistant to the fungus itself, but are simply less palatable to the beetle. Of course, the fungus can’t usually infest the tree without the beetles – but it surely would be better to be specifically equipped with genes that would protect it even if beetles did get in.

The sad tale of Britain’s elms parallels that of the American chestnut, Castanea dentata – with some intriguing contrasts. For the American Indians and for the first immigrant Europeans, the American chestnut was a wonder tree. Its nuts were a food staple – and supported 40 million wild turkeys for good measure – and its trunks provided timber. There were so many that a squirrel could travel from chestnut to chestnut from Maine to Georgia without setting foot on the ground, or so the story went.

But the overconfident forestry “improvers” of the 19th century were still not content. They began to import Asian species with bigger nuts, to crossbreed. Inevitably, the newcomers came with their own diseases. And the American chestnuts, beset by novel pathogens, succumbed. By the end of the Twenties, the American chestnut, once perhaps the commonest North American broadleaf, was all but gone.

Again, through too much zeal, the Americans felled great swathes of chestnuts to create a firewall against the spread of infection. This failed to contain the disease – but it did, so some biologists suggest, remove the myriad genetic variations from among the wild trees, which might have included some that would have conferred resistance.

By leaving our own beleaguered elms to live on in the hedges, and nurturing the few survivors, as Paul King and others have been doing, we may avoid that final fate. (In truth, the American chestnut might not quite be dead. At least, George W Bush planted one outside the White House on Arbor Day in 2005 – but it is a hybrid: 15 per cent of its genes are from resistant Asian species. It is a sad relic, like an exhumed dodo).

Overall, the message is mixed. We could see the heroic efforts of a few growers and scientists as a triumph of human ingenuity over natural adversity – the continuing tale of “man’s conquest of nature”. Or we could see this endeavour as a desperate, last-ditch attempt to ward off the consequences of our own folly. For these are tales of hubris. We thought we could do what we liked in the name of commerce. But actually, life is more complicated than we ever supposed – and in the end, it is beyond our ken. Cause and effect relationships in nature are non-linear, which means it is intrinsically impossible to predict the outcome, beyond saying it won’t be good.

Source: Telegraph newspaper

Date: 09/06/2010

UK’s Woodland Trust to plant a million trees


The Woodland Trust is to plant around a million trees on several sites across the UK to protect the “UK’s equivalent of the rainforest”,  reports Horticulture Week.

“The Plant a Tree appeal will help us plant around a million trees at five key sites across the UK, with others to come in the future,” said conservation officer Fran Hitchinson.

“The trees will buffer ancient woodland, protecting these irreplaceable sites — the UK’s equivalent of the rainforest — and thereby increase their ecological resilience.”

The trust’s 350-hectare Heartwood Forest woodland, near St Albans, will protect three ancient woods allowing wildlife to move and thrive, she added.

Low Burnhall in Durham will be bulked out by 80,000 trees to help conserve the ancient trees and create and shelter for wildflower meadows.

While Milton Woods, at the gateway to the Scottish Highlands in Stirling, will see over 180,000 trees planted to create wildlife havens for otters, owls and wading birds.

The Woodland Trust wants people to donate £15 for a tree to be planted and nurtured for 12 years.

Those who give money will be sent updates and pictures.

Source: Horticulture Week

Date: 01/05/2009

Pine voles blamed for US oak declines


Scientists trying to understand why oaks are starting to disappear from North American forests may need to look just below the surface to find some answers, says a Purdue University press release.

Researcher Robert Swihart found that pine voles, small rodents that live underground, prefer oak roots to those of other common woodland seedlings.

The study identifies the rodents as a possible factor leading to high oak mortality rates that are threatening the resource base of the hardwood industry.

“You see a lot of mature oaks, but you don’t see a lot of oaks in the understory beneath the canopy,” observed Dr Swihart.

“If you don’t see them there, you won’t see mature oaks in 20 to 30 years.

“We are facing a period in our history that could lead to a great crash in oak availability.”

Dr Swihart offered pine voles a selection of tree roots to eat in the laboratory, and they overwhelmingly gravitated toward oak roots.

Voles caused more than twice as much damage to white oak roots than northern red oak and black cherry, and more than six times more damage to white oak than black walnuts.

The study showed that the voles snubbed yellow poplar roots altogether.

“Either the oak roots were much more nutritious and had higher energy content, or they contained fewer toxins, or some combination of those factors,” he explained.

“Those are the main reasons an animal will choose one food item over another.”

His findings have been published in the Canadian Journal of Zoology.

Source: Purdue University press release

Date: 03/03/2009

Welsh woodlands to fight climate change


Climate change experts from across Europe will be seeing how the Welsh woodlands are already helping to alleviate the effects of climate change, says a press release from the UK Forestry Commission.

Researchers in Wales are putting in place exciting new ways in which the forests can help prevent flooding as well as locking away millions of tons of carbon dioxide.

Leading members of the new FUTUREforest project will be taken on a fact-finding tour of south Wales on 26-27 March, 2009.

The mission is part of the project’s remit to share experiences and new methods of environmental management to prepare the forests of Europe for climate change.

Specialists from the other six partner regions – Auvergne, France (biodiversity); Brandenburg, Germany (knowledge transfer); Bulgaria (soil protection); Catalonia (natural risks); Latvia (timber production); Slovakia (carbon sequestration) will see some of the effects of climate change on Welsh forests – and some of the solutions in and around Abergavenny.

They will see how woody debris dams, new woodland creation and other flood risk management techniques in the uplands can help to prevent the kind of flooding that has caused millions of pounds worth of damage across Wales.

The 30 strong delegation will be staying at The Hill Education & Conference Centre, Abergavenny, and visiting Forestry Commission Wales woodland sites at Mynydd Du, Usk College and the Woodland Trust’s Great Triley Wood.

“We have already begun to discover much about the way the woodlands of Europe can help us to combat climate change,” said Mike Over, Project Manager of the FUTUREforest project in Wales.

“We hope that experts from our partner regions discover that in Wales we have made some really exciting new discoveries that can help them back in their own countries.”

Source: Forestry Commission press release

Date: 19/03/2009

UN: World’s forests facing tough tests


World forests face the dual challenge of climate change and the global economic crisis, a key UN report says.

On the BBC News website, environment reporter Mark Kinver said it suggested that although the economic slowdown might reduce deforestation rates in the short term, it was also likely to lead to other problems.

One concern, would be a lack of investment in the sector and in forestry management.

The study by the UN Food and Agriculture Organization (FAO) was published on Monday.

It is timed to coincide with the start of UN World Forest Week.

CTS Nair, one of the report’s lead authors and the FAO Forestry Department’s chief economist, said the economic crisis was having “tremendous impacts – both positive and negative”.

“You will find the forestry industries in a number of countries almost on the verge of collapse,” he told BBC News.

For example, he said the construction of starter homes in the US and Canada had fallen from about two million units at the end of 2005 to less than 500,000 now.

This had led to a dramatic fall in the demand for wood products, which was affecting forest-based industries and export markets in developing nations.

However, Mr Nair added, the downturn was having some beneficial effects.

“We are seeing a decline in the prices of soya beans, palm oil and rubber etc,” he explained.

“The prices have fallen drastically, so this means that the incentives for cultivating these crops have also gone down.

“As a result, the pressure to clear primary forest stands is also declining.”

The report, State of the World’s Forests 2009, also showed that the health of forests varied from region to region of the world.

“We see advances being made in places like Europe, but losses being made in places like Africa and especially developing countries,” Mr Nair observed.

“For example, what we see in the case of Africa is that there is a growing population yet the productivity within agriculture has remained extremely low.

“There is very little diversification in terms of sources of income so there is a very high dependency level on land use and natural resources, such as timber.”

“On the other hand, in places such as Asia where there has been rapid economic growth, people have moved out of agriculture to some extent and the pressure on the land has declined.”

In recent years, the importance of the world’s forests as carbon sinks has featured prominently in global climate policy discussions.

An initiative called Reducing Emissions from Deforestation and Degradation (Redd), which is likely to involve developed nations paying tropical forest-rich nations not to cut down trees, appears to be gaining support.

Mr Nair gave the scheme a cautious welcome: “In theory, it is an excellent idea but its implementation is going to be extremely tricky.

“If you look at the people involved in forest clearing, it is different people in different regions.

“For example, in Latin America, it is largely cattle rangers and soya bean planters. In South-East Asia, it is palm oil and rubber plantations.

“What we find is that it is not the smallholders, it is the big players who are working within a global market.

“So far, only the issue of what it is trying to achieve has been examined, the issue of how we are going to implement it has not really been discussed or examined.”

Source: BBC News website

Date: 16/03/2009

Top five invasive threats to US southern forests


Apologies that this post refers to information issued in a press release by the US Forest Service back in January, but it contains interesting data and links that could be of use to people – Take Cover team.

US Forest Service Southern Research Station (SRS) ecologist Jim Miller, considered to be one of the foremost authorities on non-native plants in the  southern US, has identified the five invasive plant species he believes pose the biggest threats to southern forest ecosystems in 2009.

“Cogongrass, tallowtree, and Japanese climbing fern are among the fastest moving and most destructive non-native plant species facing many southern landowners this year,” Dr Miller warned.

“Rounding out the top five invasive species that I’m very concerned about would be tree-of-heaven and non-native privets.

“While our forests are besieged by numerous invasive plants, these and other non-native species present serious financial and ecological threats to the South and its forests.”

Non-native species often out-compete native forest plants and may degrade forest productivity, wildlife habitat, recreational values, and water quality.

Invasive species also greatly increase expenses as public and private land managers work to combat their spread and deal with their effects (such as increased wildfire risk and severity).

Non-native plants can be introduced and spread by wildlife or through other natural means.

Humans also spread invasive species by planting them in their gardens and yards and as a result of seeds hitchhiking on clothes.

Additionally, tractors and mowers used in multiple locations without being cleaned often spread the plants.

In an effort to inform forest managers, landowners, and others about where the most threatening invasive plants are in the South, Dr Miller collaborated with SRS Forest Inventory and Analysis (FIA) scientists to develop maps showing the spread, county-by-county, across the south-east of more than 30 of the most serious non-native plant species.

The invasive plant data were collected on FIA plots throughout the southern US in co-operation with state forestry agencies.

In partnership with the University of Georgia’s Center for Invasive Species Science and Ecosystem Health, SRS researchers recently posted the maps and occupation levels online.

Dr Miller hopes government agencies, forest managers, natural resource professionals, landowners, students, and others will use the information to help combat the spread of non-native plant species in southern forest and grassland ecosystems.

Source: US Forest Service press release

Date: 12/01/2009

Plant diseases threaten woodlands


Some of the finest gardens and woodlands in Britain are under threat from two closely related and aggressive fungus-like plant diseases, the BBC News website reports.

UK Environment Minister Jane Kennedy said they were attacking “pristine” locations and could potentially damage the landscape and the tourism industry.

The government has allocated £25m in a bid to eradicate the diseases which are spreading across the country.

They are Phytophthora kernoviae and Phytophthora ramorum .

Rhododendrons, a carrier of both diseases, are likely to be removed in woodland in order to curb the spread of the pathogens.

The flowering shrubs, popular as an ornamental species in many gardens, also grow wild in wooded areas and an area of the New Forest has already been cordoned off to allow rhododendrons to be cut down and burned.

Phytophthora kernoviae , first found in the south-west of England in 2003, reached Scotland five years later.

It attacks and kills many trees and shrubs, including the oak and beech trees which make up so much of Britain’s woodlands.

The Department of Environment, Food and Rural Affairs (Defra) says 69 sites in England and Wales are currently affected, with Cornwall the worst-hit region.

Phytophthora ramorum , first identified in 1995, has devastated woodland on the west coast of the United States where it has been responsible for the syndrome known as “sudden oak death”.

Few control mechanisms exist for the disease, so the importance of early detection – and proper disposal of the infected plant material – is key.

The government is to earmark some of the money for new research and development, and there will be a campaign to make landowners aware of the threat.

Source: BBC News website

Date: 03/03/2009

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