Trees: British Ash Tree

Lord De Mauley Excerpts

Monday 5th November 2012 Lords Chamber

[The Parliamentary Under-Secretary of State, Department for Environment, Food and Rural Affairs (Lord De Mauley)]

My Lords, I thank my noble friend Lord Selborne and all noble Lords for their extremely helpful contributions in this debate.

The ash is one of our most recognisable trees and we have about 80 million of them in our country. This debate focuses on the dangers to them posed by Chalara fraxinea, but of course it goes much wider. I must declare an interest as a grower of trees, including ash. The Government are taking the threat posed to the British ash tree extremely seriously. Let me start by setting out very clearly the current situation, our scientific understanding and the action we are taking. Ash dieback is a disease caused by a fungal pathogen that has devastated ash across northern Europe. With ash trees representing 5 per cent of Britain’s woodland cover, the potential impact of this disease on our landscape is significant.

I am going to try to avoid being party political, but before 2010, the scientific evidence in Europe indicated that the organism responsible for ash dieback disease was one that was already widespread and native in Great Britain. This precluded the use of import restrictions as a means of control. In 2010, new scientific evidence was published which correctly identified the pathogen that caused the disease. Between 2009 and 2012 the Forestry Commission inspected 15,000 individual ash trees across the country located in more than 8,000 groups. Of these, 103 trees were discovered to be in ill health. None of these was identified as caused by Chalara.

In February 2012, a routine nursery inspection discovered Chalara, and this finding was confirmed on 7 March. Immediately, the UK plant health authorities deployed additional resources to carry out trace-forward inspections of material known to have been supplied from the infected nurseries. Over the summer, 1,000 at-risk sites were identified and 100,000 saplings were destroyed. In parallel, the authorities developed a pest risk analysis, required, as noble Lords know, as the basis for intervention. Once completed, this analysis was fast-tracked into a shortened consultation to discover the extent of Chalara in Great Britain. During this time, the industry instituted a voluntary moratorium on imports of ash planting material, and I offer it my strong thanks.

On Friday 26 October, this consultation closed. From the early afternoon of Monday 29 October, the movement of ash from anywhere that is not a certified pest-free area—right now, nowhere has that label—became a criminal offence in time for the start of the main UK planting season at the end of November. During the consultation period, Chalara was confirmed in the wider environment in East Anglia. These trees had no apparent connection to nurseries and suggested the presence of Chalara in Great Britain for quite some time. It is possible that this infection was caused by spores blown by the wind from continental Europe, but further investigation is ongoing.

I turn now to the current situation. As my noble friend Lord Selborne said, this morning’s situation report confirmed Chalara in 14 nursery sites, 36 sites where ash has recently been planted and 32 sites in the wider environment. Over the weekend, we have confirmed that, in addition to the cases in the wider environment in East Anglia, there are also cases in Essex and Kent.

Our scientific understanding suggests that Chalara is not currently spreading. The period of spore release is normally the summer. In the winter, the main method of spreading the disease would be movements of ash material. This, as I have said, is now banned. As ash leaves fall to the ground, there exists a risk, although it is rated as low, of the spread of the disease through the long-distance movement of leaf litter on, for example, boots and tyres. In answer to my noble friend Lord King, we have no intention of unwarranted closure of woodlands to those who wish to enjoy them, but we ask woodland visitors to ensure that they take appropriate precautions when leaving woodland.

Our understanding of Chalara continues to develop. Last Thursday, Defra Chief Scientific Adviser Professor Ian Boyd convened a group of international experts to understand better the epidemiology of Chalara fraxinea. We are dealing with considerable biological uncertainty but we are determined to make the best use of the science available to tackle this pathogen.

[Lord King of Bridgwater]

I will perfectly understand if the Minister cannot answer this question now, or he may like to put a letter in the Library. He made an interesting point about why this was not identified earlier. In a sense, it was. Something that had killed 90% of the ash trees in Poland was thought to be a pathogen that was already widespread and established in this country. But we did not lose that number of trees at that time. How was it that something that killed all those trees in Poland could be thought to be widely established even if it did not kill any trees in this country?

[Lord De Mauley]

My Lords, I am not sure that I shall be able to answer my noble friend’s question entirely. I said that before 2010, the scientific evidence indicated that the organism responsible for Ash dieback disease was one that was already widespread and native in this country. But new scientific evidence was published in 2010 which correctly identified that that was not the pathogen and that a different pathogen caused the disease. I hope that that is helpful.

Professor Boyd concluded that: spores are mainly dispersed by wind during the summer; transportation of leaf litter should be avoided; Chalara will infect any form of ash, so exotic species in which Chalara is not pathogenic could act as vectors; latency from infection to overt disease is a matter of months; wood products would not spread the disease if they were treated appropriately using simple methods; trees probably need quite high doses of spores to be infected and may only become infected under specific conditions that are currently not understood; data from Norway suggest a spread rate of the infection front of 30 kilometres per year; once infected, ash trees cannot be treated; Chalara itself tends to kill only young trees; older trees are weakened and die from other causes and this can take years; there appears to be innate genetic resistance in some trees; and it appears that trees within forests tend to die most quickly because of secondary infection from, for example, honeydew fungus.

We are guided by the science. Our first priority is to establish the distribution of Chalara in Great Britain. This will inform our plan for tackling the pathogen. In this surveillance, we are determined to strike the right balance in the necessary trade-off between speed and thoroughness. There are two main surveillance operations under way. First, the Forestry Commission, whose staff have been working weekday and weekend, is undertaking a survey throughout Great Britain that will cover more than 2,000 10 kilometre by 10 kilometre squares in which sample trees will be examined. These survey areas are dispersed across the entire country, with an initial focus on East Anglia and the south-east, which are the areas at greatest risk of wind-borne infection from mainland Europe. To date, the Forestry Commission has inspected more than 1,000 of these squares, and we expect the survey to be substantially complete by the end of the week.

Secondly, the Food and Environment Research Agency is working hard to inspect sites that have been traced as receiving saplings from nurseries that have handled suspect consignments. In addition, we have asked a number of organisations, including the Country Land & Business Association, the Royal Forestry Society and the Royal Scottish Forestry Society, for their members’ help with surveillance over the next few days. I am enormously grateful for the positive way in which they have responded. This rapid surveillance will give us an indication of the extent of Chalara in Great Britain, equipping us to tackle the pathogen. On Wednesday, the Secretary of State and I will welcome industry representatives and stakeholders to a specially convened ash dieback summit. Ensuring that we are working with the science and with stakeholders is crucial to the effective management of the disease.

Noble Lords asked a number of questions. I will do my best to address them. The noble Lords, Lord Clark and Lord Judd, asked whether we could still burn ash firewood. We can. There is a very low risk of spreading the disease by moving firewood, but it will not be possible to move logs from affected areas in the United Kingdom where a notice has been served. One noble Lord asked whether burning trees would risk dissipating spores in the smoke. The indications are that that is very unlikely.

The noble Lord, Lord Clark, asked what the ban meant. All imports of ash-planting material are banned, as no pest-free areas exist in other countries. Movements of ash within the United Kingdom are banned pending full surveillance activity that will determine the pest-free zones.

Several noble Lords asked about Forestry Commission funding. While the Forestry Commission’s overall budget has decreased since 2010, it is not true to say that funding for plant health has decreased. The Forestry Commission’s budget for plant health research, which was £1.4 million in 2010-11, will be £2.1 million for 2014-15. Fera is responsible for plant health across the board. Its budget for plant health research was £667,000 in 2010-11 and will be £1.45 million in 2013-14. Defra has also allocated £1.3 million for each year of the current spending review period under the tree health action plan, and £800,000 for tree health research under the Living with Environmental Change programme for each year of the current spending review period. This funding will go one year beyond the current spending review period and will total £8 million over four years.

My noble friend Lady Parminter asked about the time taken for testing. In the lab, culturing an organism takes up to three weeks. Fera has adopted and developed a molecular method that reduces test time to less than four hours under ideal testing conditions. Following parallel trials of cultural and molecular tests, we are confident that the molecular procedure is robust, so it is currently our chosen diagnostic lab method.

My noble friend Lord King asked to what types of trees the Forestry Commission orders applied. Eradication action is required when the disease is found in nurseries or sites of recently planted ash. Containment notices are in place for those sites where the disease has been found in the wider environment pending the outcome of surveillance that is currently in progress.

The Government are taking further action in the full knowledge that Chalara will not, as some noble Lords mentioned, be the last pest to threaten our shores. Taking my noble friend Lord Selborne’s point, the Secretary of State has asked Professor Ian Boyd to convene a tree health and plant biosecurity expert task force to review our strategic approach to plant health as a whole, while at the European level, our negotiators are working to improve the pace of decision-making, the targeting of risk and the level of international co-operation within the EU plant health regime.

Furthermore, we are quickly bringing forward actions in our October 2011 tree health and plant biosecurity action plan—part of which, in answer to my noble friend Lady Parminter, importantly involves public engagement—to address the serious pests and pathogens not currently present in the UK.

I thank all noble Lords for their comments and suggestions, all of which I will take back. Chalara fraxinea is a serious threat to our ash population. We will continue to strive to understand and control it. We are also learning important lessons, which will help us combat future tree diseases.

House adjourned at 11.11 pm.