Managing Ash in Woodlands (Silviculture): Monitoring Frameworks and Permanent Sample Plots That Pay Off

Ash dieback is reshaping woodlands across the North West. The disease, caused by the fungus Hymenoscyphus fraxineus, darkens leaves, carves diamond-shaped lesions into shoots, and steadily thins crowns. Guesswork is expensive. Monitoring gives you proof. Permanent sample plots turn single visits into a repeatable picture you can trust and act on. Forest Research

Summary
Mark a handful of fixed plots. Tag the same ash trees. Revisit each summer. Score crown condition and lesions. Compare photographs year on year. Tie scores to site-specific actions. This saves money, protects the right trees, and reduces risk along roads, access tracks, and public rights of way. When an ash dieback lookalike seems possible, pause and verify before acting. GOV.UK 

Monitoring Frameworks for Ash Dieback: How to Set Permanent Sample Plots

Definition: What a Permanent Sample Plot Is

A permanent sample plot is a fixed area that you mark on the ground and on a map, then revisit at the same point in the season each year to examine the same trees. The aim is simple: build a clear record of crown condition, symptoms, and local risks so that decisions about pruning, retention, or removal are grounded in evidence, not in a single worrying walk-through. Guidance for owners and managers supports this monitor-first approach. trees.org.uk

Seven-Step Plot Method for Small Woods and Roadside Belts

Set up is straightforward and scales to gardens, shelterbelts, and small woods.

Choose Plot Size and Number

For a compact coppice or a strip along an access track, create three to five circular plots. A practical size is zero point zero five hectares, a circle with a radius of about twelve and a half metres. If that is too large for your site, use zero point zero two hectares, with a radius of about eight metres.

Fix Locations Precisely

Mark each centre with a neat timber stake or a low metal pin. Record the position with a global positioning system device or a three-word locator, and note bearings to two permanent features such as a gatepost and a mature oak. Sketch these on your plan so anyone can find them again.

Tag Trees Consistently

Attach a small aluminium tag at eye level on the north side of each ash. Record species, stem diameter at one point three metres, and a four-class crown retention score: one hundred to seventy-six percent, seventy-five to fifty-one percent, fifty to twenty-six percent, and twenty-five to zero percent of original canopy remaining.

Score Symptoms in Summer

Between July and September, look for leaf blackening and wilt, diamond-shaped lesions where side branches meet the stem, and dieback in the upper canopy. Note any brittle deadwood or basal lesions. Keep notes neat and repeatable. These months are also the best window to distinguish genuine disease from seasonal stresses. Forest Research+1

Add Target and Hazard Notes

Flag any ash within one tree length of roads, access tracks, gardens, buildings, or public rights of way. Record lean, overhanging limbs, historic failures, and nearby play areas or parking.

Set Photo-Points

From each plot centre, take a photograph facing north and another facing south. Photograph the whole crown of each tagged ash from the same stance every year. These consistent photo-points let you compare like with like.

Repeat Annually in the Same Week

Return at the same time each year with the same method and, where possible, the same people. Consistency is what turns observations into insight.

Practical Line for Play Areas and Storms

If a plot includes a play area, picnic spot, or seating, schedule an extra inspection after late summer storms. If you are unsure whether you are seeing ash dieback or an ash dieback lookalike such as drought stress, pause and seek a professional opinion before taking action. Owner guides emphasise safe retention where appropriate. The Tree Council

Ash Dieback Symptoms and What Ash Dieback Looks Like (with Lookalike Checks)

Leaves and Shoots

In mid to late summer, current-year leaves often darken along the midrib or at the base, then wilt and may hang on rather than drop. New shoots can blacken and die back from the tip. These cues are highlighted by Forest Research and the Royal Horticultural Society. Forest Research+1

Lesions and Bark

The hallmark is a sunken, diamond-shaped lesion where a side branch meets the stem. A light scrape at the margin often reveals brownish-grey inner bark. Focus inspection at last year’s nodes along small laterals; that is where lesions declare themselves. Field guides from Observatree illustrate these checks clearly. Woodland Trust+1

Crowns and Recovery Attempts

As the disease advances, the upper crown thins. The tree may respond with new shoots lower on the trunk or main scaffold branches. Owner-focused guidance notes these patterns and encourages measured responses rather than blanket felling. trees.org.uk

Fruiting Bodies in the Litter

From late summer into early autumn, look in last year’s ash leaf litter around the base. Small, white, cup-shaped fruiting bodies on old stalks are a strong clue that the fungus is active in your woodland. Woodland Trust

Two Owner Checks for This Week

Compare Same-Week Photographs from the Last Two Summers

Stand in the same place, hold the camera at the same height, and compare how much sky you can see through the crown. A steady increase is a warning; a one-off spike after a hot week often points to weather rather than disease.

Look for Diamond Lesions at Last Year’s Nodes

Run your eyes along the points where side branches meet the stem. A neat diamond outline with a sunken centre is a powerful indicator. If you are unsure, book a survey to confirm it is not an ash dieback lookalike. Woodland Trust

Ash Dieback Disease Stages and Decision Points

Early Stage: Monitor and Retain Where Safe

Leaf and shoot symptoms are present, but crown retention is above fifty-one percent. Away from targets, retention with monitoring is a sensible default. Recent research from Royal Botanic Gardens, Kew and Queen Mary University of London indicates that younger ash populations in Britain are evolving greater resistance, so safe retention can support future resilience. Kew Gardens+1

Middle Stage: Manage Trees Close to Targets

Diamond lesions are present and crown retention has dropped into the range of fifty to twenty-five percent. Trees within one tree length of roads, access tracks, gardens, or public rights of way move into a manage category. Actions include staged reduction, selective removal, or more frequent inspections timed for calm conditions. Forestry Commission Operations Notes provide the management and licensing context. GOV.UK+1

Late Stage: Act Decisively Where Risk Is High

Crown retention is below twenty-five percent, brittle deadwood is visible, or basal lesions are noted. Near roads or paths, plan removal by an experienced team with proper traffic control. Timber behaviour can be unpredictable in late-stage decline, so method and timing matter. GOV.UK 

Pros and Cons of Retaining Versus Removing

Reasons to Retain Where Safe

Retaining well-placed ash protects genetic diversity, supports emerging tolerance, and avoids unnecessary costs. The Tree Council+1

Reasons to Remove Where Risk Is High

Where people or property are at risk, removal or staged reduction reduces liability and prevents unplanned failures over busy routes. Owner guides and national guidance agree on risk-led decisions. The Tree Council+1

Practical Line for Late-Stage Trees Near Paths

If a late-stage ash stands within one tree length of a lane, bridleway, or footpath, schedule works now rather than waiting. Keep a short written record and photographs to document why, and check which permissions apply for your site. GOV.UK

North West Realities: Wet Summers, Clay Soils, Coastal Exposure and Roadside Belts

Wet Summers and Disease Pressure

Long, wet summers keep leaf litter damp and extend the period when fruiting bodies are active. Plan your monitoring for July to September, when symptoms peak and lighting is consistent for photographs. cdn.forestresearch.gov.uk

Clay Soils and Access Planning

Clay soils around Manchester slow vehicle and machine access and make rutting likely. Build in temporary ground protection and consider spreading works across two winters to keep costs predictable. Owner and contractor guidance stresses planning for safe access and appropriate timing of works. trees.org.uk

Coastal Exposure and Wind-Prone Crowns

Along Merseyside and the Fylde, strong onshore winds can turn a thinning crown into hazardous deadwood. Use your plots to prioritise interventions before the autumn gale season. trees.org.uk

Roadside Belts, Tracks and Public Rights of Way

Roadside belts and narrow farm tracks bring targets directly beneath failing limbs. Where ash overhangs a public right of way, pair monitoring with planned closures and clear signage. The Tree Health Pilot scheme in England offers grant support for managing dangerous ash along roadsides and public access routes, including elements such as traffic management. GOV.UK+1

Practical Line for Temporary Ground Protection

If your plots straddle a clay track, set out ground protection in advance and agree short closure windows. If a neighbour questions diagnosis with an ash dieback lookalike, invite them to view your photographs from the same week in successive summers.

Two Grounded Vignettes from Recent Work

Suburban Garden near Altrincham, Cheshire

Three mature ash formed a backdrop over a trampoline and seating. Our plot record showed crown retention sliding from about seventy percent to about forty-five percent over two summers, with fresh diamond lesions on a main scaffold. We retained one tree for screening, reduced one for clearance, and removed the third under controlled rigging outside school holidays. Privacy stayed. Risk fell. Costs were spread. When the owner queried a possible ash dieback lookalike after a dry July, the repeat photographs confirmed progressive decline rather than a weather spike.

Roadside Strip North of Wigan

A narrow verge on heavy clay carried frequent heavy goods vehicles. Plot scoring placed several trees in the manage band. We retained younger ash with strong crowns, added them to the plot register, and sequenced removals and reductions on calm midweek mornings with short, signed lane closures. Where doubt was raised, inspection of diamond lesions at last year’s nodes settled the diagnosis.

What to Do Next: A Simple Plan for Owners

Start with Three Small Plots

Choose three circular plots you can revisit easily. Mark them well and sketch them on a plan so anyone in your family or team can repeat the work.

Use the Two Checks

Compare the same-week photographs from the last two summers, and look for diamond-shaped lesions at last year’s nodes. These two checks catch most cases that matter. Field guides and national resources illustrate both. Woodland Trust+1

Document Permissions

Felling in woodlands usually requires a licence. Dangerous tree exceptions are narrow and should be evidenced. It is an offence to fell trees without a licence where one is required. Keep dated notes and photographs to explain why you chose each action, and check whether Tree Preservation Orders apply. Start with the Forestry Commission overview and Operations Note 46a for decisions on individual trees. GOV.UK+1

Consider Funding Routes

Where ash threatens roads or public rights of way, the Tree Health Pilot may help with costs such as access and traffic control. Review current terms and the expression-of-interest form before planning closures. GOV.UK+2GOV.UK+2

Practical Line for Public Rights of Way

If any plot includes a public right of way, set a reminder for a second safety check after late summer storms. If an ash dieback lookalike still seems plausible, request a professional visit before proceeding.

Contact Tree Surveys North West

We work across Greater Manchester, Lancashire, Merseyside, and Cheshire. If you want a monitor-first plan before you make felling decisions, we can help.

Book a Mid-Summer Assessment

We will lay out permanent sample plots, score crowns and lesions, set photo-points, and deliver a clear, risk-based action list that fits your site and budget.

Fixed-Price Reports for Roadsides and Public Rights of Way

If you need documentation for highways or public path management, we can provide fixed-price reports with photographs, plot maps, and staged work plans to support permissions and traffic control requests.

mportant note for owners in England: This article is general guidance. Tree Preservation Orders, felling licences, wildlife protections, and highway permissions are legal matters. Decisions should be made with a qualified arboricultural consultant. Dangerous tree exceptions are specific and should be documented with photographs and professional notes. Always check local authority requirements before carrying out works near public rights of way. GOV.UK+1

Further authoritative reading

• Forest Research: Ash dieback overview and survey timing. Forest Research
• Forestry Commission: Managing ash in woodlands (Operations Note 46) and Managing individual ash (Operations Note 46a). GOV.UK+1
• The Tree Council: Ash dieback guide for tree owners. The Tree Council
• Observatree: Symptom recognition and field guides. Woodland Trust+1
• Royal Horticultural Society: Identification and timings. RHS
• Bartlett Tree Experts: Technical note on symptoms and biology. bartlett.com
• Kew and Queen Mary University of London: Evidence of evolving resistance in young British ash. Kew Gardens+1

Tree Health Pilot: Grants for dangerous roadside and public-path ash. GOV.UK