Tree Pests and Diseases

Lord Bishop of Oxford Excerpts

Thursday 13th February 2020 Lords Chamber

[Lord Harries of Pentregarth (CB)]

My Lords, I too thank the noble Earl, Lord Kinnoull, and the noble and learned Lord, Lord Hope, for introducing this very important subject at such a crucial time.

I will concentrate almost entirely on ash dieback. We were slow in waking up to this terrible threat to our ash, and I am not sure that, even now, we are fully aware of the scale of the devastation upon us. Writing in 2012, George Monbiot pointed out that there had been clear signs of the disease for the previous three years and nothing had been done about it. Since then, the Government have taken a number of valuable initiatives, as outlined in the Answer to my Oral Question on 25 June last year. However, the rapidity of the spread has taken everyone by surprise. There is now hardly any part of the country unaffected. I spent last summer in west Wales, on the edge of Cardigan Bay. Normally, I look out over a field lined with the most glorious green ash on either side.

In the Bible there is a little-known form of poetic literature called a lament. The sight of those devastated ash trees provoked in me nothing less than such a lament:

“Thin branches stripped bare, stark against the sky,


Dry sticks prodding the air

Through leaves once fair,

Now drooping. O why?

Dying back. Dying back.

Fresh leaves once so green and fresh

Sagging in defeat,

Once you rose so high above the fern.

Great green Wales in slow retreat.

Dying back. dying back”.

What is happening to our trees is indeed an occasion for lament. I have mentioned ash, others have mentioned chestnut and oak, and I am sure we shall hear more about that.

We are waking up to this, but I am not sure that we have even now ascertained the scale of it. At the moment the ash is a major feature of our landscape. There are 123,000 hectares of ash in stocked woodlands, second only to oak in extent. Outside woodlands, the UK has an estimated 60 million ash trees, which represent 12% of our broadleaf. However, the ash is important not only for itself but for the species associated with it. There are 955 species associated with ash and 45 of these are thought to have only ever been found on ash trees.

This disease will be devastating not only for the look of the countryside but for all the ecological and environmental benefit trees bring. As we know, trees are fundamental to the ecosystem and play a major role in counteracting the effects of global warming and climate change by absorbing and storing carbon.

There is also the effect on human health. Trees are not only good to look at but are good for our health. Recent studies in medical journals show a correlation between the spread of ash dieback and the increase of respiratory diseases in a given area. In all, Defra has estimated that ash has a social and environmental value of £230 million per year.

One lesson to be learned from what has happened to ash dieback is the need for stricter controls on all imports of seeds and saplings. Ash dieback entered the UK from East Anglia only a few years ago and, as I mentioned earlier, spread with extraordinary rapidity. One question for the Government is whether import controls are stricter now than they were then. I am sure other noble Lords are better qualified than I am to judge whether the steps the Government have so far taken are adequate in this area.

My major concern is, first, with research. It is vital that we identify, develop and plant strains of ash which are resistant to the disease. The Government say that they have put £6 million into this but I wonder whether this is adequate for the scale of the crisis. What success has there so far been in identifying types of ash that are tolerant of the fungus Hymenoscyphus fraxineus, which blocks water getting to the leaves and causes the ash gradually to die back from the branches. When a strain of ash that is tolerant to the disease is found, a replanting programme must begin. This should be on a massive scale.

Like the noble Lord, Lord Colgrain, some noble Lords will remember—as I do—when our fields and hedgerows were resplendent with the English elm. As a result of Dutch elm disease, 60 million trees were lost in the UK in two epidemics. Only 100 were left after the last one. Now, a variety that is resistant to the disease has been identified. What is the Government’s policy on replanting elm, and what success have they had in replacing those millions of destroyed trees? It was good to hear from the noble and learned Lord, Lord Hope, about the success he has been having in Scotland not only with ash but with elm.

I hope the Government might be spurred by the example of Ethiopia, where there is a programme to plant 4 billion trees in a single year; last year, 330 million were planted in one day alone.

At the moment it is the policy in some areas—for instance, the Ministry of Defence—to fell these trees when they are diseased. Is this really the best policy? It could be argued that if they are left standing—or, at least, if they are left on the ground—all the insects we need in this country could be saved. We are now hearing about an insect apocalypse: 80% of them are about to be lost. We need to retain insect life, on which the whole of the ecosystem depends, in this country in any way we can.

Ash dieback is devastating our countryside, causing significant damage to our ecosystem, to our health—spiritual, mental and physical—and to the economy. There needs to be a sense of urgency, both in research and replanting, which we can but hope will spring from this.