The Ecological Impact of Ash Dieback in the Lake District and Cumbria

To understand the ecological significance of ash dieback in Cumbria, you first need to understand how important ash (Fraxinus excelsior) is to the native woodland of the Lake District and South Lakeland. Ash is not a peripheral species here. In the limestone woodlands of the Cartmel Peninsula, the lower Lune Valley, the Arnside and Silverdale AONB and the limestone pavements above Kendal, ash is the dominant canopy species. It shapes the structure, the light environment and the species composition of these woodlands in ways that no other tree does. When ash goes, entire woodland communities change.

Ash in the Cumbrian Woodland Landscape

Unlike the Lake District fells, which are dominated by acidic soils and sessile oak woodland, the limestone geology of South Lakeland — the Cartmel Peninsula, the Furness limestone, the Arnside coast and the carboniferous limestone country around Kirkby Lonsdale — supports a very different and in many ways richer woodland flora. Ash-dominated woodland on limestone is one of the most species-rich woodland types in Britain, characterised by a ground flora that includes:

• Wild garlic (ramsons)
• Dog's mercury
• Early purple orchid
• Herb paris
• Lily of the valley
• Wood sorrel
• Toothwort
• Hart's tongue fern

This ground flora community depends on the particular light regime created by ash canopy — lighter than oak, more seasonal, allowing a longer growing season at ground level before the canopy closes in late spring. As ash dies and the canopy opens permanently, or is replaced by faster-closing species like sycamore, these ground flora communities will change, and in some cases disappear.

The Wildlife That Depends on Ash

The ecological consequences of ash loss extend far beyond the ground flora:

Invertebrates

Ash supports a specialised community of invertebrates found on no other tree species. The Agrilus biguttatus beetle (ash bark beetle) is the most notable, but there are dozens of invertebrate species associated specifically with ash bark, wood and foliage. The loss of ash from British woodlands will cause local extinctions of some of these species in the near term.

The ash leaf is also the food plant for several moth species, including the centre-barred sallow, the coronet and the privet hawk moth, all of which are present in South Lakeland. These species will need to find alternative host plants or face local population declines.

Bats

Mature ash trees are important bat roost trees across Cumbria. The combination of deep fissures in mature ash bark and the tendency of older ash to develop large cavities makes them attractive roost sites for a range of bat species, including brown long-eared bat, Daubenton's bat and noctule. As mature ash trees die and are removed from the landscape, the availability of quality bat roost habitat will reduce — a particular concern in the limestone South Lakeland landscape where bat populations are already under pressure from habitat fragmentation.

Birds

Several bird species are closely associated with ash woodland in Cumbria. Redstarts, pied flycatchers and wood warblers — all declining summer visitors whose UK populations are concentrated in the upland oak and mixed woodlands of the north and west — all use ash woodland. Barn owls regularly nest in hollow ash trees in the South Lakeland farmland landscape.

Lichens and Bryophytes

The bark of mature ash trees in the humid, high-rainfall environment of the Lake District and South Lakeland supports some of the most species-rich lichen and bryophyte communities in England. The smooth, nutrient-rich bark of ash is a very specific habitat that other tree species do not replicate well. Some of the lichen species found on old ash in the Cumbrian limestone landscape are genuinely rare and will face significant threat as the ash canopy disappears.

What Replaces Ash — and Whether That Matters

One of the most important and poorly understood questions about ash dieback is what will replace ash in the woodland canopy over time. In many Cumbrian woodlands the answer, without active management, is likely to be sycamore — a vigorous non-native species that is already abundant across much of South Lakeland and the Lake District and which regenerates aggressively. Sycamore is a less ecologically valuable replacement than ash in most respects, particularly for the specialist invertebrate communities and limestone ground flora that ash woodland supports.

In some locations, wych elm (Ulmus glabra) may expand to fill some of the gap — it is a native species present in many South Lakeland woodlands and supports a richer invertebrate community than sycamore. Elder, hawthorn and hazel may also expand in the shrub layer as the ash canopy opens. The outcome will vary significantly between sites.

The critical point is that active management influences what comes next. Woodland owners and managers who take a proactive approach — selectively removing dying ash, controlling sycamore regeneration and encouraging native species — will end up with much better ecological outcomes than those who simply allow natural succession to take whatever course it takes.

Are Any Ash Trees Resistant to Dieback?

This is one of the more encouraging aspects of the ash dieback story. Research by the Woodland Trust, Forest Research and the John Innes Centre has identified that a small proportion of ash trees — estimated at between 1% and 5% — show significantly greater tolerance to Hymenoscyphus fraxineus than the majority. These trees do not appear to be immune, but they show much slower progression of the disease and may be capable of surviving long term.

Identifying and retaining tolerant ash trees is now a conservation priority. If you have ash trees on your land in Cumbria that appear to be showing less severe symptoms than surrounding trees — good crown condition, less die-back, healthier foliage — it is worth flagging this to your local woodland management contractor or to Forest Research. These trees may carry genetic traits that will be important for ash recovery in the longer term.

The Woodland Trust's Ash Tag project allows members of the public to record and monitor individual ash trees, including those that appear tolerant. It is well worth participating if you have ash trees on your land.

What Cumbrian Landowners Can Do

The ecological consequences of ash dieback are largely beyond any individual landowner's control. But there are meaningful actions that landowners and woodland managers across Cumbria can take:

• Identify and retain tolerant ash trees — don't fell everything. Assess each tree individually and retain those showing genuine tolerance where it is safe to do so.
• Control sycamore regeneration — in woodland where ash is dying, actively managing sycamore regeneration and favouring native species in the gaps will significantly improve long-term ecological outcomes.
• Restock with diverse native species — where ash is being felled, replanting with a diverse mix of native species rather than a single alternative reduces the risk of a similar monoculture problem in the future. Good species for limestone South Lakeland include wych elm, field maple, hazel, wild cherry, spindle and guelder rose alongside the more familiar oak and birch.
• Consider Countryside Stewardship — woodland management for ash dieback can qualify for Countryside Stewardship funding. We can advise on eligibility and help prepare management plans to the required standard.
• Retain some standing deadwood — where it is safe to do so, leaving some standing dead ash provides valuable habitat for the invertebrate and bat communities that ash supports. A complete clear-fell of all dead ash removes this habitat at a stroke.

Get Ecological Woodland Management Advice in Cumbria

We work with private landowners, estates, nature reserves and local authorities across Cumbria and Lancashire on ash dieback management that balances safety, ecology and practicality. If you have ash woodland and want to think carefully about how to manage the transition, we are happy to discuss your situation.

Phone/WhatsApp: 07376804724
Email: enquiries@maxreynoldstreeservices.com

Contact us here | Woodland management in Cumbria | Forestry contracting | Tree planting and restocking | Our ash dieback overview guide