Tree Pests and Diseases

Earl of Kinnoull Excerpts

Thursday 13th February 2020 Lords Chamber

[The Earl of Kinnoull (Non-Afl)]

My Lords, it is a pleasure to follow the noble and right reverend Lord, Lord Harries, and his compelling contribution. Ash is a key part of our garden, and the dieback disease is one glen away from us in Scotland. I also thank and congratulate my noble and learned friend Lord Hope. He volunteered to lead the debate, and did so in a far better and more adept way than I could ever have done. Every time we go to New Zealand, we will all remember his story about the pine cone. I fear that I have been a bit guilty of that as well—also from southern California.

We are the stewards of our islands’ environment, and that environment is fragile. The very essence of that environment, and the diversity of flora and fauna it supports, is our native trees. There are today about two oaks for every member of the population. Without the oak, Nelson would have had no ships and this palace would have no panelling and very little furniture. Ash provided the shafts for the arrows at Agincourt, beech gave us the stocks for the muskets at Waterloo, and birch plywood made the wings of the “Wooden Wonder”, the Mosquito.

We enjoy fantastic forestry conditions in these islands. Mild winters, plentiful rainfall, fertile soil and hill-sheltered topography all interact for the good, and growth rates exceed those of mainland Europe. At the end of the First World War less than 5% of Britain’s land surface was wooded. Although this has now risen to 13%, we have far to go. Across the EU, woodland coverage averages 38% of the landscape. I note that France, Germany, Spain and Italy have more than 30% of their landscape covered. All of us in the Chamber are aware of the positive contribution to climate change problems that forestry could make.

Some 44,000 people are employed in UK forestry and primary wood processing, with a GVA of £2.1 billion. How those figures could rise if we were able purposefully to increase our acreage of well-managed woodland—but our native trees have never faced a more formidable spectre of threat than they do today from disease and pests. There are many diseases, and I regret that I do not have time to go into any of them, but, like other noble Lords, I note the absolute necessity for excellent biosecurity and good research.

So I turn to pests. The disease battle is interconnected with pests, as they can be vectors for disease, as both direct carriers and as weakeners of trees, either by opening up wounds that allow secondary attack or simply by stressing the plant. The worst and most destructive of all pests is the grey squirrel. Here, I declare my interests as set out in the register as chairman of the Red Squirrel Survival Trust and of the UK Squirrel Accord. Grey squirrels were first introduced into this country in 1876 in Cheshire. Between 1876 and 1930, around 500 animals are recorded as having been released into the wild. By 1930 or so, awareness had risen sharply of the damage that grey squirrels do to broadleaf trees and to red squirrel numbers, and that was the genesis of anti-grey squirrel feeling. The 500 grey squirrels introduced up to 1930 have grown into a grey squirrel population that 90 years later is estimated at 2.7 million.

The problem where broadleaf trees are concerned is that the grey squirrel ring-barks younger trees to get at the sap. This ring-barking causes terrible wounds to the tree, killing up to 70% of them and making the timber quality of the remainder poor. It is no wonder that grey squirrels and the threat that they pose are, alone, responsible for the dearth of new broadleaf commercial planting in the south-east of England, with all the biodiversity, wildlife and climate advantages that it would bring.

The challenge posed by grey squirrels as the leading threat to trees has given rise to the UK Squirrel Accord with its 37 signatories, comprising the four Governments, their nature agencies, the principal voluntary sector interested parties and the principal private sector representative entities. The Squirrel Accord has commissioned a fertility control project at the Animal and Plant Health Agency which, it is hoped, will perfect a suitable active substance and hopper delivery method to allow simple fertility control to shrink grey squirrel numbers significantly, in turn allowing forestry a chance. We are entering the third of five years of research involving scientists in the UK, the USA and France. Significant progress has been made; I pay a warm tribute to the Minister for his support and encouragement, for APHA reports to him. I look forward to hearing what he will say on this element of the battle against the multiple threats.

The grey squirrel and, indeed, the deer problem—to which the noble Lord, Lord Colgrain, referred—are today well managed by some landowners but not at all by others. In the future, the co-operation of all land managers will be vital. This necessity for land-manager engagement applies across all the major environmental and climate challenges that we face.

Before I close, I will make one further point. The oak processionary moth—to which the noble and learned Lord, Lord Hope, referred—was accidentally introduced into Britain in 2005. The oak processionary moth strips trees bare, leaving them weakened and vulnerable to other threats. By the start of 2019, all 33 London boroughs had had outbreaks. While £37 million has been spent by government on control, I regret that the problem seems to have spread to Bracknell and Virginia Water. While this large expenditure is necessary, I note that the research expenditure requests for pests and squirrels are for far lesser sums. I do hope that this balance—between expenditure on control and expenditure on research to try to combat the problem—is carefully considered by the Government.

I close by asking the Minister whether he believes that he has sufficient powers and resources for the battle against the many threats that we are discussing today.