Once hailed as the leading example of how to fend off a major tree disease, Brighton and Hove now appears to be home to a growing Dutch elm disease threat. But what happened? 

INNOVATION and dedication saved Brighton and Hove’s elm trees from Dutch elm disease (DED) and the city’s 19,000 elm trees logically became the National Elm Tree Collection. Lots of people contributed, but Rob Greenland (senior arboriculturalist and arboricultural manager) was clearly central to this success over his three-to-four-decade period of service.

When I went to Brighton and Hove in October 2012, Rob was close to retirement and duly hung up his arb boots the following year. As I recall, succession to his position was not ‘cut and dried’; neither was whether it would come about as a promotion from within or an appointment of someone from outside. In the case of Brighton and Hove’s unique programme for the management of elm bark beetles and their deadly DED cargo, you might, on balance, settle for continuity.

I have no idea who took over from Rob. In the following years I was preoccupied with Chalara ash dieback, oak processionary moth and Phytophthora ramorum (sudden larch death), with no time to think about Brighton and Hove’s collection of elm trees, which had looked safe for the foreseeable future.

However, I started to read disturbing stories about how the beetle was biting back and threatening the city’s elm trees more seriously than at any other time since the initial DED pandemic in the 1970s. These reports picked up in pace and by the early 2020s were a flood. Brighton and Hove is well served with quality local newspapers and so there is never a problem in accessing news stories about the city’s elms which are close to the hearts of the community.

Forestry Journal: The Preston Park Twins sported a remarkably fine head of foliage for 400-year-old English elm trees. The Preston Park Twins sported a remarkably fine head of foliage for 400-year-old English elm trees. (Image: FJ)

The first indications that something was going wrong came in July 2013. Four diseased trees in Old Steine Gardens and one elm on the University of Sussex’s Falmer campus were felled. Brighton and Hove City Council environment committee chairman, Pete West, described the events as “extremely worrying”.

The elm at Falmer campus was a fine specimen standing 25 metres high and with 150 years on the clock. Reasons for the ongoing resurgence of disease were first raised at that time.

Andy Jupp, the university’s assistant director of estates and facilities management, raised the issue of elm logs destined for firewood being imported into Brighton and Hove from elsewhere in Sussex where the disease was rife.

Martyn Stenning, an environmental biologist at the University of Sussex, said the hot and dry weather in summer 2013 had produced the perfect conditions for both the beetle vector and the fungal pathogen, which the beetle carries and transmits. Neil Brothers (council arboriculturalist) confirmed that the council was encountering sporadic outbreaks, but added that it was too early to say how serious the problem was.

Brighton and Hove’s elms were under threat, but not always from DED. A huge Wheatley elm at Brighton College was under threat of removal, not from DED, but because it was in the way of a new development. And a 120-year-old Wheatley elm found itself in the way of a road improvement plan at Seven Dials Junction, with the council claiming the tree’s roots were damaging the pavement and blocking the view of the pedestrian crossing. Nothing is sacred, even ancient and veteran elm trees, when it comes to new concrete.

I was lucky to have seen the Preston Park Twins (pollarded ancient English elms) which had stood side-by-side in Preston Park, North Brighton, for over 400 years, having been planted in 1613 during the reign of James I. The first ‘twin’ showed signs of infection in 2017 and was felled in 2019. Then in September 2021 the council announced the remaining twin had the disease, which took hold on a large limb. Council arborists carried out emergency work, including girdling of the limb below the infection, to try and stop the infection spreading to other parts of the tree. Council arborists were hopeful because the DED season was due to end in several weeks with the onset of cooler autumn weather. As far as I know the tree still stands today.

Forestry Journal: Elsewhere in England there are plenty of English elms still to be seen but they are invariably root suckers from where mighty mature elms once stood.Elsewhere in England there are plenty of English elms still to be seen but they are invariably root suckers from where mighty mature elms once stood. (Image: FJ)

A particularly bad DED outbreak occurred in summer 2021 when 50 diseased elms in Coldean Woods had to be felled. Coincidentally or not, the elm trees were on and around a new housing development in Coldean Lane. The council wanted to remove the trees immediately to stop any disease spread, but the presence of badger setts in the wood held up things while Natural England secured the safety of these nocturnal mammals. It would have been a lot easier and cheaper to call in DEFRA’s sharpshooters who would undoubtedly be pleased to add to their present bag, which currently stands at 210,000 badgers.

In August 2022, a dozen elms in the grounds of Downs View Life Skills College in Old London Road, Brighton, were found to have the disease and were too far gone to be saved. Resurgence of DED is still on the rise because 850 diseased elm trees had to be felled in summer 2023. Reports now refer to the city’s 17,000 elm tree collection, which is measurably down from the 19,000 trees quoted during my visit in 2012. DED had come back for a second bite of Brighton’s elms and was clearly eating into the city’s National Elm Tree Collection.

Elm logs to burn

So why has Brighton and Hove’s unique and model defence system against the elm bark beetle apparently broken down and laid bare the National Elm Collection to DED once more? It would appear that urban England’s new-found obsession with firewood to heat homes is a double-edged sword, at least as far as Brighton and Hove and its irreplaceable collection of elms are concerned.

Fears were first raised in 2015 when the city’s elms were already going down with DED at a frightening rate. At that time, Ian Brewster, arboricultural manager for Brighton & Hove City Council, said: “It is imperative for the survival of the internationally recognised National Elm Collection that residents take responsibility for their actions when purchasing logs. If in doubt, always ask the log merchant beforehand what species of wood they sell. If elm is mentioned, then don’t take them. If you suspect elm logs are in the delivered bags, or are loosely piled, then please inform our team immediately.”

Everything appeared to come to a head in December 2019 after the city lost one of the iconic Preston Park Twins. Brighton & Hove City Council said it firmly believed that infested elm logs, imported into Brighton and Hove from outside of the city’s limits and destined for firewood, were responsible for the infestation by elm bark beetles which carry the fungus causing DED.

On Boxing Day 2019, an interesting letter appeared in the Daily Telegraph written by a resident of Brighton and Hove, commenting on an article in the Daily Telegraph’s Nature Notes (15th December) – ‘Log ban to curb Dutch elm beetle’.

Forestry Journal: Fears are that resurgence of Dutch elm disease will pick off Brighton and Hove’s iconic elms one by one. A superb English elm at the Brighton Pavilion Fears are that resurgence of Dutch elm disease will pick off Brighton and Hove’s iconic elms one by one. A superb English elm at the Brighton Pavilion (Image: FJ)

The reader was bemoaning a move by Brighton & Hove Council to ban elm logs for use as firewood within the ‘city’s’ limits, although it subsequently turned out to be ‘stern advice’ rather than a legally-enforced elm log ban. There alongside the letter was a picture of elm logs and butts left on the landscape and referred to as ‘trap trees’ and claiming how such debris attracts elm bark beetles and therefore prevents them from infecting healthy elm trees.

What does Brighton & Hove City Council have to say?

Faced with these conflicting messages it was time to hear what Brighton & Hove City Council had to say on the matter, so I clicked on the their website.

The message was quite clear – “Please don’t buy, store or bring elm logs into the city [Brighton and Hove]. We’re calling on people not to use elm tree logs this winter for their fires and wood burners. Elm logs are the perfect breeding ground for bark beetles that carry and spread [Dutch] elm disease which is devastating the city’s historic elm tree collection. To alert people to the danger elm logs pose, we’ve erected large signage at four strategic points in the city which have high levels of people passing on foot and by vehicle.”

The signs said: “[Dutch] elm disease is destroying our historic elm tree collection: If you’re buying wood logs this winter, please:
• don’t buy elm logs – always check with the seller
• don’t bring elm logs into the city – this spreads the disease
• don’t store elm logs in your home or garden – the infectious beetles will still breed
The actual transmission of Dutch elm disease can result from:
• fungal inoculum carried by elm bark beetles and transmitted to healthy elm trees which develop Dutch elm disease
• Dutch elm disease is transferred underground via root grafting between adjacent diseased and healthy trees
• Roots of newly planted elm trees becoming infected via fragments of diseased root material left in the soil following the removal of a diseased tree.”

The council also asked everyone to check their logs were not elm. If owners were unsure about the species provenance of their logs the council said it would check them free of charge. 

Trap trees and beetle traps

So what about the relevance of so called ‘trap trees’ and specifically in relation the elm tree/elm bark beetle/DED association and situation? There is nothing new about the concept of trap trees, which have been widely researched for various beetle insect pests in forestry. You can add to this the current obsession with leaving deadwood in situ in the cause of biodiversity, including for the benefit of non-pathogenic fungi, arthropods and higher animals further up and along the food web using such deadwood resources for food and shelter. Indeed, I leave deadwood all around my garden to the clear benefit of birds, hedgehogs and rodents, which feed on the populations of arthropods thus created and cultivated.

But living elm is uniquely vulnerable to elm bark beetles carrying and transmitting a fungal pathogen responsible for a fast-acting terminal disease.

Forestry Journal: Despite the Preston Park Twins sporting fine foliage, both had hollow trunks which presumably made them more susceptible to infection with Dutch elm disease.Despite the Preston Park Twins sporting fine foliage, both had hollow trunks which presumably made them more susceptible to infection with Dutch elm disease. (Image: FJ)

And in this context the authorities in Brighton and Hove are clearly right to warn against purchasing, moving, storing and using elm logs, let alone leaving them on the ground as so-called trap trees.

Any future plans involving insect trapping would be more effectively and safely executed by extending use of custom-designed elm bark beetle traps loaded with multistriatin, the aggregation pheromone of the smaller European bark beetle (Scolytus multistriatus). This would not only provide a much more flexible option around when and where the traps are deployed, and subsequently removed, but crucially retain trapped beetles. Dead elm wood deployed as ‘trap trees’ may well attract beetles – but which can later fly off in search of alternative food sources in the form of healthy elm trees.

Elm as firewood

Since elm wood as a domestic fuel is at the centre of this conundrum, it is worth considering the merits of elm as firewood. Slow burning with little or no flame is the most common assessment, with the biggest complaint related to the splitting of elm logs, which is described as a devil’s own job.

Several old poems and rhymes relating to wood burning appear to support these comments. 

Relevant stanza in the age-old rhyme ‘Logs to burn’ says: “Elm logs burn like smouldering flax, no flames with them are seen.”

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The more recent ‘Firewood Poem’ published by Lady Celia Congreve (Poet and World War 1 nurse) in The Times on 2 March 1930 says: “Elm wood bums like churchyard mould, E’en the very flames are cold.”

However, if you really want to know how elm wood burns, then find an English arborist who started his/her career in the early 1970s. These professional arborists, now at or beyond official retirement age, will tell you how as young men and women they spent the first few years of their working lives felling countless huge old English elm trees and consigning them to funeral pyres, which burned continually for days on end.

Can one man or woman make a difference?

I thought back to my meeting with Rob Greenland and whether one man can make a difference. Rob certainly did during his 30– to 40–year period of service for Brighton & Hove City Council. Things apparently started to go pear-shaped shortly after he retired, which may or may not be coincidence. If infested firewood coming into Brighton and Hove from outside is the reason for the resurgence of DED, and the unfettered financing of surveillance, tree pruning and tree removal within the city’s limits and beyond has been maintained, then it would appear to be coincidence. That said, having met Rob and knowing his record I would like to think he would have called for much more stringent rules and regulations around movement of elm logs into and around Brighton, and its sale as firewood.