Ash Dieback Disease

Debate between Julian Lewis and Lord Goldsmith of Richmond Park

Monday 12th November 2012 Commons Chamber

[Zac Goldsmith (Richmond Park) (Con)]

I welcome the recent action that my right hon. Friend the Secretary of State for the Environment, Food and Rural Affairs has taken to tackle ash dieback, imposing an import ban and restrictions on movement; initiating a national survey to map the extent of the disease; and hosting a summit of forest experts to identify ways of tackling ash dieback in the short term and tree health generally in the long term, on which point I wish to focus briefly.

It is hugely worrying that, as we heard from the Minister, there are 150 confirmed sites with ash dieback, but we need to keep sight of the fact that this is just one of many of the growing number of invasive pests and diseases threatening the UK’s native trees. Seventy per cent. of horse chestnut trees are affected by bleeding canker in some parts of England. Our iconic English oaks are in serious trouble, wilting under assault from acute and chronic oak decline. In part of my constituency, up to 50% of our oaks show signs of acute oak decline. It has been claimed by The Daily Telegraph—so it must be true—that there are more ancient oaks in Richmond park than in all of Germany and France combined. Even if we halve that and allow for a little exuberance, it is still a tragedy to think that these great oaks are facing a very serious threat.

In March, the usually fatal sweet chestnut blight was found to have hopped the channel from France. Sweet chestnut is the main tree species in an estimated 30,000 acres of woodland in Britain. According to a recent report by Robin Maynard of the Countryside Restoration Trust—I declare an interest as a trustee of the CRT—25 new pests and diseases are already established, recently arrived, on their way or seen as likely threats to our trees. Clearly, that is not just a rural problem; a high proportion of the trees under threat are planted in urban areas. For instance, plane trees constitute one 10th of all trees in the capital, and the plane wilt fungus has ravaged 80% of plane trees in France. Last year, French officials revealed that all 42,000 plane trees lining France’s historic Canal du Midi, a world heritage site for the past 10 years, in southern France, would be felled because of the disease.

What is happening? Research implicates a greatly expanded horticultural trade in imported species as the main Trojan horse for new pests and diseases. It accounts for up to 70% of invasive introductions to the US and anything up to 90% to the UK. It is believed that Phytophthora ramorum in larch came in on one viburnum shrub imported from the EU to a nursery in Cornwall in 2002. A batch of maples imported into the EU and Britain from China was found, despite being certified pest-free by the Chinese authorities, to be infested with Asian longhorn beetles. Oak processionary moth infestations have been tracked back to one large specimen oak brought in from Holland. It came in roughly six years ago, and in my constituency it has grown exponentially. The tragedy is that the annual cost of just managing the oak processionary moth is probably what it would have cost to deal with it outright in the year when it was detected. It costs £200,000 a year in Richmond park alone, not to mention Kew gardens and other such areas.

The Woodland Trust has pledged to support community and local tree nurseries to help to ensure that new tree planting is rooted in the community. Obviously, that is welcome. One thing many of us can do is ensure that, when we plant trees, they are UK-grown and disease-free. It seems absurd that we are importing ash trees, when there are hundreds of millions in the UK already.

The famous Mrs Beeton advised in her “Book of Household Management”:

“No matter how small your garden, always ensure you leave at least three to four acres for trees”.

[Laughter.] It was a different time. Small gardens do not normally have four acres sitting idle, but at one point or another most of us will plant a tree, so this is a lesson we can learn. As the Institute of Chartered Foresters has pointed out, the difficulty is that, whatever we do now, the arrival of more pests and diseases is inevitable. We therefore require new and more resources, if we are to get to grips with this growing problem, and we need to build greater resilience into our woods and forests.

DEFRA had reallocated £8 million over four years for new research into tree health. In the context of this discussion, that is not enough. Let me put that figure into perspective. The annual cost to UK forestry from pests and diseases has been put at about £130 million. That is bound to be an underestimate, reflecting the low value we attach to trees, not just in industry but culturally, socially, environmentally and so on. If the Asian longhorn beetle were to become established in the UK, based on the experience of the US authorities in eradicating it, it would cost £1.3 billion to attempt to do the same here —and there would be no guarantee of success either.

[Dr Julian Lewis (New Forest East) (Con)]

As part of a solution, is my hon. Friend advocating restrictions on imports, not just for ash but for other varieties of trees and shrubs?

[Zac Goldsmith]

Yes. We know the benefits of trade, but they pale in comparison with the costs of unwanted stowaways, so we need to take a far stricter approach to restricting imports, particularly for larger trees, which have become increasingly fashionable. The ones with large earth balls allow even greater opportunity for the introduction of unwanted species.

In his written ministerial statement on Friday, the Secretary of State said that he was prepared to consider radical proposals. I want to add one thing. As well as encouraging more local sourcing of trees and greater vigilance by the horticultural trade, I urge the Government at least to consider requiring the relevant horticultural sectors to contribute more to the cost of inspection services and forestry research. With 90% of invasive tree pests and disease attributed to imports, the horticultural and landscaping sectors should surely bear a proportion of the costs of preventing and containing outbreaks. It is a sad reflection on successive Governments that it has taken this tragedy to focus minds on the issue of tree diseases. This must be a turning point.