We’re often told of the need to take large-scale action against grey squirrels in the British Isles, to protect young broadleaf trees, preserve our native red squirrel population and combat climate change. But do all the arguments add up? And could other actions achieve the same ends?

WE have a climate change committee led by a lord and made up of top-flight academics, while the UK government gives Tata Steel half a billion quid to close the blast furnaces at Port Talbot Steelworks and sack 3,000 workers. This and a lot more is done in the name of net zero, but apparently to no avail. That’s because, according to another peer of the realm, ‘grey squirrels are sapping UK efforts to combat climate change’. The account of what was said in a House of Lords debate was plastered all over the national press and was mentioned by Forestry Journal

Frankly I find it difficult to believe that grey squirrels, despite being prime spoilers of silviculture, could scupper net zero. It sounds to me like politicians passing the buck for the UK’s woeful record on tree planting. 

Anyway, the gist of the argument goes like this. Grey squirrels are undermining the UK’s ability to tackle climate change. Bark gnawing and stripping activities by the alien invasive rodent mean landowners are not planting the trees needed in the drive to reach net zero. 


This was said by Lord Kinnoull during a debate on biodiversity in the House of Lords. Lord Kinnoull is an independent crossbencher who chairs the UK Squirrel Accord, a partnership of conservation and forestry organisations, government agencies and private companies. The aims of the Squirrel Accord are to halt the decline of the native red squirrel, improve woodland habitats and reduce numbers of the currently dominant grey squirrel.

Lord Kinnoull said: “The biggest threat to our broadleaf woodlands is the grey squirrel. They ring bark trees aged between 10 and 40 years, making them susceptible to a host of pathogens and thus killing many and damaging much, if not all, of the rest in the affected plantings. This greatly reduces the yield and quality of timber. This has resulted in many landowners and managers in England simply not planting native broadleaf trees that are needed as a significant part of our net-zero strategy.”

Forestry Journal: Many landowners are reluctant to plant broadleaf trees because of the damage grey squirrels do – a good reason to plant conifers instead?Many landowners are reluctant to plant broadleaf trees because of the damage grey squirrels do – a good reason to plant conifers instead? (Image: Stock image)

This is mostly true, but I would take issue with his lordship on ring barking. Whether ring barking is carried out by a rodent vandal using teeth or a human vandal using a machete, it actually kills the tree all on its own, without any assistance from plant pathogens. Having destroyed a complete circuit and circumference of vascular tissue, there is a break in the movement of water upwards in the xylem and soluble food downwards in the phloem. 

Everything above the continuous, circumferential cut dies. What happens below and to the tree’s root system varies depending on whether the species has the capability and capacity to sprout. Whether or not ring barking opens the way for plant pathogens is neither here nor there, because the tree dies anyway.

He went on to highlight UKSA-commissioned research into using an oral contraceptive as a non-lethal way to manage grey squirrels, funded in part by Defra.

Lord Kinnoull said: “I hope that it does not seem ungrateful to the minister to observe that much larger sums of government money are being spent in other individual areas of disease and invasive alien species.”

You can understand his lordship wanting some of the money dished out to cope with the continuous stream of alien plant pathogens visiting our shores and destroying our trees, but the invasive alien pathogen argument is invalid. That’s because grey squirrels kill trees directly by ring barking. And they don’t need to wait for Chalara ash dieback, sweet chestnut blight or some other disease, which Lord Kinnoull presumably has in mind, to finish the job at a later date.

These broader aspects of biosecurity and quarantine were taken up by another independent crossbencher, the aptly named Lord Trees, a vet and former president of the Royal College of Veterinary Surgeons, who stressed the importance of biosecurity.

He said: “Although it may be difficult – indeed financially, practically and politically impossible – for us to prevent the emergence of infectious disease threats in other parts of the world, we do have the ability to try to reduce the risks of incursions of infectious diseases into the UK while allowing, as far as possible, unhindered trade.”

Hear, hear.

And what did the government have to say in reply? Environment minister Lord Douglas-Miller said: “Protecting the biosecurity of the United Kingdom is at the forefront of this government’s agenda.” Really? Pull the other one minister, there’s grey squirrels on it.

Frivolities aside, an important implication emerged when Lord Kinnoull said: “This has resulted in many landowners and managers in England simply not planting native broadleaf trees that are needed as a significant part of our net-zero strategy.” 

Native broadleaves are not the only tree in the basket when it comes to the contribution of tree planting to net zero. All sorts of reasons are aired for not planting conifers, so why not use grey squirrels as a reason for not planting broadleaf trees and planting conifers instead? Ah, you might say, but grey squirrels will also bark-strip larch, Norway spruce and pines. The list of trees damaged by grey squirrels is ‘endless’ but they do have favourites, which tend to be broadleaves.

Forestry Journal: Red squirrels are now a rare sight in Britain, but as a species they are not in danger.Red squirrels are now a rare sight in Britain, but as a species they are not in danger. (Image: Getty/stock)

So the solution is simple. Just as some landowners plant sycamore amongst oak as a sacrificial species, why not plant English oak among Douglas fir for the same purpose?

In any case, it can be argued that their impact on British broadleaves is just one reason to do away with grey squirrels. A cull also appears necessary to help preserve our population of native Eurasian red squirrel (Sciurus vulgaris).

However, ecologist Nigel Dudley has questioned that thinking in his new book, Why Biodiversity Matters. Dudley, who has worked with organisations like the World Wildlife Fund and UNESCO, says he is looking at the situation from a global perspective rather than a UK context. He points out that while the red squirrel is under real threat in the British Isles, it is an abundant species across large parts of Eurasia, listed in the ‘least concern’ category by the International Union of Nature (IUCN). 

He says this raises doubts over whether measures to boost its numbers, including potential culls of grey squirrels, make sense, economic or otherwise. “We put a lot of money into maintaining red squirrels in Britain,” he said. “And that’s culturally important, because people get really excited about seeing them. But as a species they are not in danger. On a global scale, there are loads of red squirrels. So if we’re worried about biodiversity, putting time and effort into defending red squirrels against grey squirrels in Britain shouldn’t be a priority.”

Last year the UK government said it would put £25 million towards a ‘survival fund’ to support a range of species including red squirrels as well as hedgehogs and grey seals, although these two are also listed as being of ‘least concern’ by IUCN.

Dudley questions the wisdom of investing in animals just because they are considered cute or charismatic, especially if they are doing relatively well in other countries. “It’s misguided in terms of the fact that there’s quite a few endemic species [native species found only in certain areas of the UK] that are not being addressed by conservation at all at the moment,” he said. “But of course, they’re less interesting. They’re things like lichens and mosses, maybe a few moths – things people don’t think about and probably never even see.” 

Of course, even if you subscribe to Dudley’s reasoning and you agree with his views there are other ways of looking at the whole grey versus red squirrel scenario. Grey squirrels are calculated to cost the UK £37 m per year in lost timber value. Removing grey squirrels would therefore save a lot of money, with the added bonus of allowing red squirrels to recolonise most of their old historical haunts.