Beset by difficulties, ash is in decline across the country and we should celebrate it while we still can, writes Dr Terry Mabbett.

COMMON ash (Fraxinus excelsior) continues on a steep decline, entirely predictable since Chalara ash dieback (Hymenoscyphus fraxineus) reared its head in 2012. Dissemination by air-borne spores, systemic damage to vital vascular tissue in ash trees and no gene-based resistance to leaflet infection by spores left little leeway. The scene was clearly set for rapid and widespread destruction of an irreplaceable native tree.

Oak may be first for biodiversity and reputation as hardwood timber, but ash timber has never been fully exploited in the British Isles. Landowners began to fell ash trees in 2013 to pre-empt deterioration of standing timber. An enterprising East-Anglian company started to export ash logs to Asian countries where British-grown ash is now in fashion for making doors, windows and wain-skirting. A chapter in H.L. Edlin’s Woodland Crafts in Britain (1949) called ‘Ash Crafts’ shows ash was once prized for everything from spears and oars to hockey sticks and handles, but not for construction.

Ash thrives in a wider range of environments than oak, including leaner soils and at higher altitudes, assisted by unbeaten colonizing capability. Ash has a more versatile reaction to cutting to produce pollards and coppice, while mature trees can come back after natural failure or felling. In this context, ash is our most important high-forest tree.

The ash tree’s fate can be likened to that of English elm (Ulmus procera), though ash is truly native whereas English elm was introduced by the Romans. Another key difference between common ash and English elm is that ash regenerates by seed whereas the self-sterile elm was propagated by suckers. As such, all English elm was effectively identical, standing no chance if confronted with Ophiostoma novo-ulmi or Dutch elm disease (DED). However, a wider genetic base doesn’t appear to be helping common ash to beat Chalara. There is evidence of disease tolerance in some trees, but plant breeders are yet to produce natural ash genomes authentically resistant to infection by spores.

Forestry Journal: Close-grown woodland situations will produce an altogether straighter, narrower and taller common ash tree.Close-grown woodland situations will produce an altogether straighter, narrower and taller common ash tree.

Will the destruction of ash by Chalara follow the same path as English elm and DED? The respective pathogens have much in common, including membership of the Ascomycota (the sac-forming fungi). Both cause a lethal disease, fast-spreading and deep-seated in the vascular tissue (xylem and phloem) to disrupt movement of water, mineral nutrients and soluble sugars, with predictable consequences.

Salient differences between English ash and elm in relation to eventual fate are: (1) seed regeneration by ash versus clonal credentials of English elm, and (2) dissemination of spores in air currents by Chalara and via elm bark beetles for DED.

Elm bark beetles are attracted by plumes of volatile chemicals (para-pheromones) released by damaged elm bark tissue. Colonising beetles release insect aggregation pheromones which attract more beetles. Faced with a sophisticated insect vector ferrying fungal spores, there was no escape, even for isolated elms in parks and on golf courses. The only trees to escape were those protected by peculiarities of geography and topography in locations like Brighton and Hove.

Forestry Journal: Constantly moving shade cast by common ash canopies is created by wind-induced movement of the long-stalked, supple and feathery, fern-like leaves with their constituent leaflets.Constantly moving shade cast by common ash canopies is created by wind-induced movement of the long-stalked, supple and feathery, fern-like leaves with their constituent leaflets.

However, root suckering ensured elm’s survival, albeit as a hedgerow shrub. Suckers grow into poles which survive until bark is sufficiently thick to support the beetles. Transmitted disease kills the pole but not the rootstock, which lives on to sucker another day. The death of English elm was swift, done and dusted in less than a decade.

Woodland ash and hedgerow ash may disappear, but isolated trees in towns and cities have epidemiology on their side. Dr Anne Chandelier in Belgium mapped the vertical profile of Chalara ascospores released from fruiting bodies (apothecia) on dead ash rachises on the ground. She showed spore concentration was 30 times higher at 0.5 m than 3.0 m above ground level, while lateral movement for the majority of spores was less than 50 metres from the point of liberation. And Chalara ascospores (unlike some other fungal spores) lack a thick coat containing melanin to prevent destruction by desiccation and UV radiation.

All of this has been largely ignored by UK forest and tree authorities because Anne Chandelier’s findings on spore structure and flight capacity clearly blow a big hole in the preferred theory of Chalara arrival in Britain by being blown across the sea in a reverse of H.E. Bates’ famous novel Fair Stood the Wind from France. In reality, Chalara arrived over several years on huge consignments of ash planting material imported from Europe.

Chalara is most devastating up an uninterrupted profile of ash foliage from ground level on regenerating seedlings in woodlands, ash shrub in the hedgerow and coppice ash stools. Ash trees in parks without understorey baggage and lowest foliage high up the tree should have some protection. Indeed, such ash trees are still largely free of Chalara and should remain so, good for sight and soul, because only when ash is open-grown outside woodland do canopies come into their own.

Forestry Journal: Fraxinus the Phoenix – common ash has the remarkable ability to grow back from apparent terminal failure.Fraxinus the Phoenix – common ash has the remarkable ability to grow back from apparent terminal failure.


Every cloud has a silver lining, even a cloud of Chalara spores. If we do lose common ash and you should come to miss it, you can always seek solace in poetry and prose.

The Poem of the Battle of Maldon (Essex) marks very early reference to ash used as a spear: “Byrhtnoð maþelode, bord hafenode, wand wacne æsc (Byrhtnoth made a speech, raised his shield, waved his slender ash-spear).” The Battle of Maldon took place on 11 August 991, during the reign of Æthelred the Unready. Earl Byrhtnoth and his thegns (lords) were fighting a Viking invasion.

Many know the old rhyme around ash, oak and summer rainfall:

‘Oak before the ash will be a splash

Ash before the oak will be a soak.’

And everyone should know that ash never comes into leaf before the oak (in the same location). It was to reassure country folk that summer would be fine for growing and ripening the corn. However, there is lots more to be found about the ash in the archives.

Ash is the last to re-foliate but first to defoliate in autumn, typically after the first flurries of wind and rain, the compound leaves dropping their elliptical leaflets one by one. And not being rich in tannins (like oak and beech), ash leaflets quickly disintegrate. The poet Philip Edward Thomas refers to this.

‘The leaflets out of the ash-tree shed,

Are thinly spread,

In the road, like little black fish, inlaid,

As if they played.”

From: ‘After Rain’ by Philip Edward Thomas (1878–1917)

John Betjeman, poet laureate from 1972 until his death in 1984, highlighted two key qualities of the ash tree in a single stanza of his poem ‘Upper Lambourne’. In winter conditions, ash can be an uninspiring tree but not if colonised by ivy, which changes the illumination profile. A characteristic of ash in summer is the constantly moving shade cast by the canopy.

‘Up the ash tree climbs the ivy,

Up the ivy climbs the sun,

With a twenty-thousand pattering,

Has a valley breeze begun,

Feathery ash, neglected elder,

Shift the shade and make it run.’

From: ‘Upper Lambourne’ by John Betjeman (1906–1984)

Burning ash was viewed as a waste of good timber, even though ash was claimed to be the original Yule log. However, ash possesses the peculiar quality of burning well when green, as recognised by Walter de la Mare.

‘Of all the trees in England,

Her sweet three corners in,

Only the Ash, the Bonnie Ash,

Burns fierce while it is green.’

From: ‘Trees’ by Walter de la Mare (1873–1956)


Those looking to the Old English Masters for comfort should look north to the ‘Old Ash Tree’ painted by Scottish artist Edward Arthur Walton (1860–1922). His meadow ash brilliantly depicts how open-grown ash, like oak, spreads its wings. Paintings by English artist John Constable (1776–1837) most often depict elm and his classic ‘Study of Ash Trees’ appears botanical when in contrast to his more familiar styles. 

Almost 200 years later, contemporary North American artist Lauren Sansaricq (born 1990) painted a magnificent Hudson Valley scene with an ‘Old Ash’ in the foreground showing branch, foliar and bark detail not dissimilar to our own ash (and most timely too with the uncompromisingly lethal emerald ash borer killing ash trees in over 30 states including New York).

Common ash should be recorded and remembered on film before it is too late. Use your camera and record the ash tree’s idiosyncrasies: matt-black winter buds, non-descript flowers, stumps springing back from tree failure, pollards, coppice, hedgerow ash, pioneer seedlings and bunches of brown, dry keys which rasp in the breeze.

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