Ash Dieback Disease

Barry Gardiner Excerpts

Monday 12th November 2012 Commons Chamber

[Mary Creagh]

There has been confusion on both sides of the House about what the former Secretary of State, my right hon. Friend the Member for Leeds Central (Hilary Benn), who is in his place, did or did not do. He asked the Department for Environment, Food and Rural Affairs to do a thorough search of all the ministerial papers he saw on ash dieback, which has shown that he did not see the correspondence between the Horticultural Trades Association and the Forestry Commission about a possible import ban. The only mention of ash dieback was in a briefing note in February 2010, in which the disease was listed as absent from the country. The hon. Member for Mid Norfolk (George Freeman) chairs the all-party group on life sciences, so he should know that the way the disease has been discovered is still evolving.

In 2009, it was thought that the fungus that caused ash dieback was already present in the UK. It was only subsequently that a new virulent species causing ash dieback was discovered. The science changed in 2010, when a new pathogen, Hymenoscyphus pseudoalbidus, was identified as the fungus causing the disease. I advise all hon. Members to read an article by Andy Coghlan in the New Scientist of 31 October that gives the scientific chronology of the disease. I also have a copy of the scientific paper in Forest Pathology in which the change was first discovered, which was printed in 2011.

What did my right hon. Friend the Member for Leeds Central do? He published the “Forestry Commission: Science and innovation strategy for British forestry 2010-2013” on 1 April 2010. It stated:

“Over the next five years we will increase our budget for monitoring and biosecurity research particularly with regard to tree health to 15% of our research spend.”

Even as late as autumn 2011, the Forestry Commission pathology bulletin confirmed that Britain was clear of the pathogen.

[Barry Gardiner (Brent North) (Lab)]

The hon. Member for Bury St Edmunds (Mr Ruffley) made a fair point about the possibility of airborne transmission. Does my hon. Friend the Member for Wakefield (Mary Creagh) agree that there may be connectivity with nurseries to which seedlings were imported? It is quite possible that, over a year, there was airborne transmission to trees, as the hon. Member for Bury St Edmunds suggests, from those imported seedlings. That is not incompatible with his point.

[Mary Creagh]

It is much more likely that the disease spread from imported seedlings transplanted from nursery stock than that it blew in, on great gusts, over the North sea. We will examine that in more detail later. [Interruption.] Ministers can chunter; the science is not politically convenient for them, but we will stick to what continental scientists have discovered until those facts are disproved.

The disease was discovered in imported saplings in February this year. When did the public first hear that the infection was on UK soil? Was it in April, when Ministers were told that it had been discovered in a nursery? No. Was it in June, when it was discovered in newly planted sites, and there was increased risk to mature woodland, as the disease could blow in from those sites? No, it was not. We finally heard on 25 October, when the Secretary of State announced that he would ban ash imports during Department for Environment, Food and Rural Affairs questions in the House—a full eight months after the disease first appeared.

Ministers could have started the consultation on a ban back in April, instead of leaving it until the end of August. The question on everyone’s lips is: “Why didn’t they?” The Secretary of State told the House on 25 October:

“The minute we heard about this, we launched a consultation.”—[Official Report, 25 October 2012; Vol. 551, c. 1066.]

Does he understand that a consultation is not a ban? Why did Ministers keep the public in the dark? This really matters, because scientists have lost eight months in our fight against ash dieback, as the diseased leaves have already fallen. I congratulate the university of East Anglia on its ashtag.org app and website, but what a shame it did not know that there was a problem in April, when Ministers did. Ministers’ incompetence has meant that we are behind the curve of the disease’s spread. This matters because we, the public, who love our forests, may have unwittingly spread the disease from June to October, the main fruiting season for the fungus. Had we known in spring, we could have completed a comprehensive survey this summer, using public good will. Ministers’ incompetence has helped the disease spread and will cost the taxpayer money.

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[Mary Creagh]

As a scientist, does the hon. Lady understand epidemiology? The dots are all different colours: the red ones represent mature woodlands, and there are others for trees planted out in newly planted sites and nursery sites. The ones in the south-west are in nursery sites: there are no red dots in the south-west, ergo the disease seems to have spread from—[Interruption.] My theory, and it has yet to be disproved—[Interruption.] No, I shall come on to that, but I wish to make progress. I shall explain it to the hon. Lady.

[Barry Gardiner]

Will my hon. Friend give way?

[Mary Creagh]

No, I shall make progress.

We had a 15-minute briefing from the Secretary of State last Wednesday, for which I am grateful, and we discussed the spread of the disease with Ian Boyd, DEFRA’s chief scientist. A document containing 10 key scientific facts was produced last Wednesday. Bullet point 10 said:

“Wind-blown spores may be dispersed up to 20-30 kilometres, (high confidence)”.

I was therefore surprised at the briefing to hear that the infection had blown in on the wind across the channel and the North sea, even though the channel is 30 km wide at its narrowest point. I was even more surprised, as the week went on, to learn that it had blown hundreds of miles across the North sea to infect mature trees in Northumberland and Scotland.

The key scientific facts document is quite clear:

“Longer distance spread occurs via infected plants or potentially via wood products”.

That would explain the infection in the south-west that the hon. Member for Totnes (Dr Wollaston) is worried about. However, it is politically inconvenient to have a disease which Ministers knew was in the country, with saplings left to infect their wild and mature cousins. I grew suspicious when I realised that the Forestry Commission's key scientific facts, published on Wednesday, changed over the weekend. Bullet point 10 now says:

“Wind-blown spores cause the disease to spread up to 20-30 km per year”.

The inconvenient fact that the wind blows the spores just 20 to 30 km has completely disappeared. A whole new fact, however, has emerged:

“On occasions, spores may disperse much further on the wind.”

However, unlike every other key scientific fact that is categorised as low, medium or high confidence, there is no scientific reference to back up this new scientific fact, because there is none. As yet, I have not seen any evidence to back up Ministers’ claims about the wind. The disease has moved slowly and predictably across Europe, yet now it has developed new powers to cross great seas on the wind.

Is an alternative scientific theory possible? Is it not possible that ash dieback has spread to mature trees in Northumberland and Scotland from the infected saplings that were planted out last winter and on which the fungus fruited this summer? It is certainly possible, and I would argue more probable than those gusts of wind.

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[Mr Heath]

The honest answer to the hon. Lady is that, surprisingly, very little work has been done on this. As she may imagine, we have reviewed all the scientific work that has been done across Europe, not only on pathogen identification but on silviculture, to see how to mitigate the effects of the disease. We have all been struck by how little work has been done and the great need for us better to understand the disease, how it develops, and how to develop proper resistance to it. She raises a perfectly proper point to which the answer, our scientists having reviewed all the literature and talked to their European counterparts, is that we are not as far advanced in our understanding as we perhaps ought to be given how long the disease has been endemic across the continent.

[Barry Gardiner]

The Minister is being extremely generous and courteous in giving way so often; I am grateful. He said that the first time the disease was positively identified was in April this year in stocks in a nursery. Can he therefore explain to the House, because this question is being widely asked, why it was not considered appropriate at that point to introduce a ban on imported ash seedlings? Many people look at this and say, “It was found in a nursery and we knew that these were imported seedlings, so why was the ban not put in place at that point?”

[Mr Heath]

The answer is that we do not import at that time of year and therefore no imports were coming in. The most important thing to do was to carry out a very detailed search as to where imports had taken place, going on from there to identify where sales and possible plantings had taken place so that we could identify any infected seedlings and have them destroyed. That was the thrust of what we were doing. As the hon. Gentleman is aware, we also then went to consultation on the import ban, but we needed to know exactly the extent of what was happening, and the time scale meant that there were no plantings going on at that time of year.

This calendar is very important to hon. Members’ understanding of exactly what has happened. For instance, a lot of people have the mistaken impression that we are now finding that the disease is suddenly spreading. It is not; it does not spread at this time of year because we are out of the sporulation season. We are identifying possible symptoms of disease, most of which have been there for a very long time—two years, three years, or perhaps more—in the trees in the wider environment that we had discovered to be infected. It is very important that people understand what is happening now.

Let me return to my point. When Chalara was discovered, additional resources were deployed to trace ash trees known to have been supplied from infected nurseries, and over the summer 100,000 young ash trees were traced and destroyed. In parallel, the authorities developed the pest risk analysis that was required to support the precautionary action taken and to justify continued intervention—that is part of my answer to the hon. Member for Brent North (Barry Gardiner). Such analysis was the basis for a fast-track consultation to strengthen evidence and seek views on an import and movement ban on ash trees. As I said, that took place outside the main planting season, but the industry took the sensible precaution of instituting a voluntary moratorium on imports of ash-planting material.

We can be reasonably sure—not absolutely sure—that no ash seedlings were imported during the summer, other than through very casual means such as if someone brought one back in their car boot. The hon. Member for Wakefield (Mary Creagh) asked me in an urgent question whether I could guarantee that no one had brought back an ash seedling in their car, but I am afraid I have not looked in every boot of every car, so I cannot give that guarantee. I can, however, give a reasonable assurance that commercial imports of ash seedlings did not take place during the summer.

[Barry Gardiner]

The Minister says that a ban on imports was not considered necessary because it was not believed that there would be imports at that time of year. Does he therefore accept that the horticultural trade and industry would have suffered no commercial detriment by the imposition of such a ban, and that prudence and risk analysis might have led him to do so?

[Mr Heath]

Again, I return to the fact that to impose a statutory ban, we must have evidence to suggest it is necessary. That is why we developed such evidence, which was put out in the consultation. The most important point is that plant importers recognised the potential damage the disease could do, and imposed a moratorium that stopped trees coming into this country over the summer. A statutory ban was not needed for that, but we ensured nevertheless that it was introduced at the earliest possible opportunity.

None of that activity was compromised by cuts to the Forestry Commission budgets, as the hon. Member for Wakefield suggested. Although its overall budget has taken cuts since 2010, funding for plant health has not been reduced. Indeed, a bigger share of the Forestry Commission’s budget is now dedicated to plant health than previously, and spending by the Department for Environment, Food and Rural Affairs in that important area has increased. The hon. Lady knows that to be the case because she asked questions and got answers, even if she is not prepared to accept them.

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[Mr Heath]

I can confirm what the hon. Lady asks—the DCLG and the LGA specifically attended Cobra meetings, so they are fully in the loop. We have given advice to the LGA for dissemination to local authorities, which understand their responsibilities. The Highways Agency is also involved—a point about transport links was made earlier. We are conscious of the fact that some new plantings are inevitably associated with major road systems—and, indeed, the railways—and we are taking great care to ensure that those trees are inspected and appropriate action taken.

Most of the cases confirmed in the wider environment are clustered in the east and south-east of England—in Norfolk, Suffolk and Kent. A few cases have been found further west or extending north up the east coast. The disease is present in mature trees in those areas. That pattern suggests two things. Chalara fraxinea first came to Britain through spores blown on the wind from continental Europe, and the advice from the specialists who know about these things is that it has been here for some time—at least two years, and possibly more.

[Barry Gardiner]

I am grateful to the Minister for giving way again so generously. The scientific advice that we have received says:

“Local spread may be via wind, rain splash or even transmission by insects. Over longer distances the risk of disease spread is most likely to be through the movement of diseased ash plants.”

That does not accord with the idea that the disease first had its impact on these shores after being blown across the North sea or the channel by wind; it suggests that it would have come here in saplings with the contagion then spread on the wind locally.

[Mr Heath]

The hon. Gentleman’s theory—it is also the theory of the hon. Member for Wakefield—does not accord with the advice of the leading experts—[Interruption.] The hon. Lady talks about “scientific facts”. I think that displays her underlying problem with understanding how science is developed. We can deal only with the most probable reason for the evidence that is put before us. The leading experts from the United Kingdom and Europe—whom we brought together over the last two weeks under the leadership of DEFRA’s chief scientific adviser, Professor Ian Boyd—have reviewed the evidence and said that what they see is consistent with a view that the disease is brought in by wind-blown spores.

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[Mr Heath]

No, I do not want the hon. Lady to believe that. Actually, I believe that there has been hugely greater mobility of goods and people in recent years, which has spread disease. That is of real concern to all of us, and we need to deal with it. All I am saying is that, according to a detailed analysis, the incidence of ash dieback disease in this country is consistent with its having been brought in by wind-blown spores. That is what all the leading scientists are telling us, and I see no reason to disbelieve them or to involve some conspiracy theory.

[Barry Gardiner]

Will the Minister give way?

[Mr Heath]

I think I will make a little more progress. I may give way to the hon. Gentleman later.

[Barry Gardiner]

rose—

[Mr Heath]

Well, all right. One more time.

[Barry Gardiner]

I am very grateful to the Minister. He has said that, according to the scientists, the incidence of the disease is consistent with its having been carried in by the wind. Of course I take his word for that, but he has used the same phrase repeatedly, which has led me to worry. Are the scientists saying that the incidence of the disease is consistent with its having been carried in by the wind, or are they saying that the wind is the most likely vector for its transmission? What do they believe is the most likely vector?

[Mr Heath]

When we have completed all the epidemiological modelling, we shall be in a better position to answer that question. At present, it is perfectly proper to recognise that the likelihood—

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[Barry Gardiner (Brent North) (Lab)]

I am delighted to follow the hon. Member for Richmond Park (Zac Goldsmith), who made many of the points I wished to make.

Serious and genuine questions need answering about the genesis of Chalara fraxinea in the UK. Did the Horticultural Trades Association warning in 2009 go unheeded by DEFRA officials? Were Ministers made aware of that warning? When they were informed on 3 April of the infection in Buckinghamshire, why did they not impose a movement ban? When Crowders nursery in Lincolnshire notified officials in June this year that the disease was found in 15 of its trees, did DEFRA officials really issue it with a notice to stop it taking action? Did they put trade rules above environmental health? When the disease began to take hold in Poland in 1992 and other parts of continental Europe later on, did the EU take adequate steps to regulate and control its spread?

Is it credible to claim that wind-blown spores reached the UK from across the sea, from Denmark, given that scientific advice states that wind-blown spores can spread 20 to 30 km per year and that local spread may be via wind, rain, splash or even transmission by insects, but that over longer distances the risk of disease spread is most likely to be through the movement of diseased ash plants? Given that the UK introduced national measures to prevent the entry and spread of the disease on October 29, why did it claim that it could not do so to nurseries and growers previously? Did UK nurseries that became aware of the danger of Chalara fraxinea then stop importing seedlings from suppliers in infected countries, or did they rely on Government advice, rather than their own trade association?

All those questions will no doubt eventually be answered, and no doubt not all of them without embarrassment to politicians, officials and the industry. My focus today, however, is on examining the response that the Government must make to the increasing threat that our landscape and biodiversity face from climate change and the new vectors of disease that climate change has brought with it. In its excellent report published earlier this year, the Independent Panel on Forestry specifically addressed the need

“to see our wooded landscapes, in both rural and urban settings, being better protected from, and more resilient to future risks such as climate change, pests and diseases.”

It specifically recommends that the Government

“should speed up delivery of the Tree Health and Plant Biosecurity Action Plan by additional investment in research on tree and woodland diseases, resilience and biosecurity controls.”

The key question arises: have they speeded up the delivery of the action plan? I remind the House that the body meant to examine this was set up by my right hon. Friend the Member for Leeds Central (Hilary Benn), the Secretary of State for the Department for Environment, Food and Rural Affairs in 2010. The key diseases and pest identified at that time were sudden oak death syndrome, oak processionary moth and Phytophthora ramorum in larch. I believe that Chalara fraxinea was mentioned only as a disease predominantly in Europe that might manifest itself in the UK.

Perhaps one of the more foolish cutbacks imposed by the Government has been the freeze on public information spending. I ask the Minister how on earth the Government propose to combat infectious diseases in plant health if they constrain their own ability to communicate directly with growers and the industry, and rely on the passive mechanism of their own website. It has been estimated that the changing risks arising from climate change and the new vectors of disease will result in a decline in timber yield in England of up to 35% by 2080, according to the Forestry Commission’s report “Climate Change Risk Assessment”, published in February.

In the past 12 months, the Forestry Commission has reported increasing incidence of Phytophthora lateralis, which attacks Lawson cypress, Phytophthora ramorum, which attacks beech and rhododendron—itself a non-native invasive species, but now a part of the UK landscape—acute oak decline and Cryphonectria parasitica, which affects sweet chestnut. To these diseases, we must add pests such as the Asian longhorn beetle in broadleaf woodland, the pine tree lappet moth on native heath land, and oak processionary moth in beech and hornbeam—to name only a few of the most serious new threats.

The number of outbreaks of these pests and diseases has risen more than twelvefold over the past 40 years. It is one thing to identify these risks to our landscape, but it is quite another to develop a mitigation and adaptation plan to combat the way in which they might impact on our biodiversity and on the ecosystem services that our forests provide. Such a plan will not be cheap. Last year in the United States, the Animal and Plant Health Inspection Service’s eradication programme for the Asian longhorn beetle alone cost US$33 million.

I urge the Government to understand that it is not enough to have a plan to tackle Chalara fraxinea. They must develop a framework in which all the new vectors of risk that threaten our landscape can be tackled. That means having a clear understanding of the value of the ecosystem services that our trees and forests provide. The Government must look to the national biodiversity action plan and the national ecosystem assessment for a blueprint for a comprehensive response. The key message of the UK national ecosystem assessment begins:

“The natural world, its biodiversity and its constituent ecosystems are critically important to our well-being and economic prosperity, but are consistently undervalued in conventional economic analyses and decision making.”

Natural capital has not been properly accounted for, and the services that our forests provide through provisioning, habitat for pollinators, watershed protection and soil stabilisation are considered—

[Mr Deputy Speaker (Mr Nigel Evans)]

Order.