Trees: British Ash Tree

Earl of Selborne Excerpts

Monday 5th November 2012 Lords Chamber

Asked By

[The Earl of Selborne]

To ask Her Majesty’s Government what steps they are taking to protect the future of the British ash tree.

[The Earl of Selborne]

My Lords, I thank all noble Lords who put their names down to speak in this debate, which comes at a slightly later hour than perhaps we expected. I declare an interest as chairman of a farming company that has woodlands and a fruit nursery.

The word “crisis” is often overused in the context of environmental concerns, but the sudden realisation that the British ash could go the way of the elm in the 1970s is without doubt the recognition of a crisis. I will start by setting out the facts as I understand them. I am sure that if I get them wrong, the many experts who are due to speak will be able to put me right. Ash dieback disease is caused by a fungus called Chalara fraxinea. The disease was probably introduced to northern Europe on nursery stocks from Asia. Over the past decade it has had a devastating effect on the ash trees of northern Europe. It was first confirmed in Britain in March 2012, on young ash trees in a nursery in Buckinghamshire. Subsequently, other sites of infection were discovered, linked to imported nursery stock from Europe.

Last month, ash dieback was identified in older, native trees in woodlands in East Anglia. I will bring noble Lords right up to date by saying that today the Forestry Commission and Defra reported that after a weekend of intense activity by volunteers and experts, Chalara had been identified in 82 locations, including 14 nurseries, 36 planting sites and 32 forests and woodlands, including some in Kent and Essex. Last Friday, the count was 52 rather than 82, so the expectation must be that as surveillance and monitoring extend, many more sites will be identified.

While cases of infection in nurseries are clearly caused by importing infected stock, cases in mature trees in woodlands in the east and south-east of England are thought to have been caused by spores that were blown from the continent, or which possibly were brought in by migrating birds. In August, the United Kingdom plant health authorities undertook a pest risk analysis on ash dieback, which concluded that once trees are infected, they cannot be cured. However, the analysis also stated that not all trees die of the infection; a number are likely to have genetic resistance. Swedish research suggests that this number might be significant.

The pest risk analysis formed the basis of a fast-track consultation that ended on 26 October. On 29 October the Government introduced a ban on ash imports and the movement of trees. At the same time, Defra’s Chief Scientific Adviser, Professor Ian Boyd, was asked to convene a tree health and plant biosecurity expert taskforce. A number of companies have proposed treatment solutions for Chalara, which Defra has promised its scientists will rapidly evaluate. So much for history; I recognise that this is almost a running commentary on a fast-moving epidemic.

The public reaction has been one of disbelief that once again we have been caught by surprise by yet another threat to a native tree species from invasive pests and diseases. After the disastrous outbreak of Dutch elm disease in the 1970s, when we lost more than 30 million elms to a new and more virulent fungus spread by beetles, we were challenged by a plethora of tree pests and diseases, including acute oak decline, which is of great concern, particularly in the east of England; plane wilt; chestnut blight; and bleeding canker of horse chestnut, to name just four from a much longer list. Time and again we seem to act too late. For all those diseases, as for ash dieback, we put in place policies once we had found that the diseases were already with us. What we need are measures aimed at keeping out these serious pests and pathogens and such measures need putting in place years ahead of the anticipated arrival of the disease.

We knew years ago that ash dieback was a threat. We discussed four years ago with the European Commission's standing committee for plant health whether an import ban might be appropriate, but it seems that we were not able to produce the scientific evidence to justify a ban then. Instead of a ban on imports, which we now have, we carried out a small-scale survey. By the time Defra launched its Tree Health and Plant Biosecurity Action Plan in October 2011, ash dieback seems to have been relegated to a low priority. Indeed, there were plenty of problems in this country on the tree health front to deal with. This allocation plan allocated £7 million over three years to tackle tree diseases. That is not just on research, but on all other measures that might together address these issues.

Ahead of that biosecurity action plan, the Forestry Commission produced in May 2011 a revised table of top pests and pathogens that threaten tree health in Great Britain—a list of about 16 species. This listed the prioritisation criteria for potential impact for each disease: its risk or probability of entry and its expected economic, social or environmental damage. Those were the right questions to ask. The problem is that having asked the right questions no one seems to have answered the questions correctly or alerted the Secretary of State that ash dieback, although not yet thought to be in this country, like many of these other diseases, was an imminent threat, that its economic, social and environmental damage could be enormous and that we should act immediately to ban imports of ash plants. Defra got permission for the ban in October. Why on earth could the scientific evidence for justifying the ban not have been produced three or four years ago when the Horticultural Trades Association and others were asking for a ban on ash imports?

We do have a taskforce convened by Professor Ian Boyd charged with reviewing our approach to plant health. Rather than dwell on our failures in protecting plant health let me list what this taskforce now needs to recommend. Landowners and the public need to be assured that whenever a suspected incidence of an infection of whatever disease is reported, a rapid identification service will be provided. Detection and identification methods using molecular approaches such as the portable DNA tests have undergone rapid development and tight targets for response rates must be set. We need greatly to increase the surveillance, monitoring and inspection of nurseries and plantations.

The Forestry Commission has lost a significant proportion of its staff in the field. Its regional staff used to be able to spend much more time in the woodlands and forests, and they knew their forests. Likewise, its research capacity has declined. Research on pests and pathogens of trees is woefully underfunded, whether in universities or research institutes, and bears no correlation with the cost to the economy of woodland pests and diseases or to their impact on society. An assessment must be made of eradication and containment methods for ash dieback and indeed for other diseases, reviewing the role of a quarantine system for plants and plant passports for species for which the import ban does not apply. We need to develop biological control approaches such as looking for natural enemies to these new pathogens.

Trees are a long-term crop and amenity. Our approach to this sudden threat must be long term. We need to recognise that within our ash population there will possibly be some strains of ash with resistance to dieback. We need to protect this diversity. I hope that the Minister will assure the House that tree health will in future be given the priority it deserves and that if the taskforce comes up both with short-term and long-term recommendations that command the confidence of experts, the forestry sector and the public, the Government will without reservation commit to implementing those measures.

[Baroness Northover]

My Lords, I remind noble Lords that, unlike previous debates this evening, this is a strictly time-limited debate and that, therefore, when the clock reaches six minutes, noble Lords have had their full time.