Common Tree Diseases in Northumberland | Tree Health Advice

Common Tree Diseases We See Across Northumberland & The North East

Trees across Northumberland, Cumbria, the Scottish Borders and the wider North East face a wide range of environmental pressures from prolonged wet weather and storms to pests, fungal pathogens and disease.

While some tree diseases are now widespread across the UK, certain conditions are particularly relevant across Northern England and southern Scotland due to the region’s climate, woodland coverage, mature tree populations and exposure to wet ground conditions.

At TC Tree Services NE Ltd, we regularly encounter trees affected by fungal decay, disease and decline during tree inspections and management work across domestic properties, estates, roadsides and rural land.

Ash Dieback (Hymenoscyphus fraxineus)

Ash Dieback is now one of the most significant tree diseases affecting the UK and is widespread throughout Northumberland and the wider North East.

The disease affects Ash trees and is caused by a fungal pathogen that spreads through airborne spores. Once infected, trees can progressively decline over a number of years.

Common signs include:

• Thinning canopies

• Dead branches within the crown

• Diamond-shaped lesions on stems

• Epicormic growth lower on the trunk

• Progressive dieback throughout the canopy

Ash is an extremely common species across rural Northumberland, roadside boundaries, estates and hedgerows, which is why the disease has become such a major management issue across the region.

One of the biggest concerns with Ash Dieback is how brittle infected Ash trees can become, particularly once significant decline sets in.

Honey Fungus (Armillaria)

Honey Fungus is a common fungal disease found across the UK and is frequently associated with declining trees, hedges, shrubs and woodland areas.

It spreads underground through root systems and can attack stressed or weakened trees, gradually affecting their ability to absorb water and nutrients.

Signs may include:

• White fungal sheets beneath bark near the base

• Black bootlace-like rhizomorphs in the soil

• Declining foliage and dieback

• Honey-coloured mushrooms appearing seasonally around the base

Honey Fungus is commonly encountered in mature gardens, wooded properties and long-established landscapes throughout Northumberland and the Scottish Borders where root systems and older planting schemes are extensive.

Phytophthora

Phytophthora is not a single disease but a group of water-mould pathogens capable of affecting a wide range of tree species.

It is particularly associated with:

• Waterlogged ground

• Poor drainage

• Prolonged wet conditions

Because Northern England and the Scottish Borders experience high rainfall and saturated soils for large parts of the year, Phytophthora related decline is something increasingly encountered across the region.

Affected species may include:

• Larch

• Horse Chestnut

• Beech

• Alder

• Ornamental trees and shrubs

Symptoms vary depending on species and pathogen type but may include:

• Crown thinning

• Bleeding lesions

• Root decline

• Reduced vigour

• Sudden dieback

In some cases, infected trees can decline surprisingly quickly once root systems become compromised.

Bleeding Canker of Horse Chestnut

Bleeding canker is a disease commonly affecting Horse Chestnut trees across the UK, including many mature roadside and parkland trees throughout Northumberland and the North East.

The disease causes lesions on the stem and branches which can produce dark, sticky fluid, often referred to as bleeding.

Common symptoms include:

• Dark bleeding patches on the trunk

• Crown thinning

• Dieback

• Reduced vigour

• Structural weakness over time

Horse Chestnut trees are widely planted throughout towns, estates, schools and village greens across the North East, which is why bleeding canker is something regularly monitored within mature populations.

Not every infected tree requires removal, but management and monitoring are often important depending on severity and location.

Ganoderma

Ganoderma is a type of decay fungus commonly found at the base of broadleaf trees throughout the UK.

It is particularly associated with:

• Oak

• Beech

• Plane

• Lime

• Horse Chestnut

Ganoderma fungi decay wood within the lower stem and root system, which can affect the structural stability of a tree over time.

Visible signs may include:

• Bracket fungi near the base

• Crown thinning

• Reduced vigour

• Areas of decay around buttress roots

Ganoderma is frequently encountered in mature urban and parkland trees across Northumberland, Newcastle and the wider North East due to the large number of ageing broadleaf trees within public and residential spaces.

Importantly, the presence of Ganoderma does not automatically mean a tree is unsafe. The significance depends on:

• The extent of decay

• The species affected

• The surrounding targets

• The overall condition of the tree

Professional assessment is often required to determine appropriate management.

Why Tree Disease Monitoring Matters

Many tree diseases develop gradually over time and symptoms are not always obvious from a distance.

Regular inspections can help identify:

• Early decline

• Structural defects

• Fungal activity

• Deadwood development

• Stability concerns

In many cases, sensible management and monitoring can help retain trees safely while reducing future risk.

Professional Tree Advice Across Northumberland & The North East

At TC Tree Services NE Ltd, we regularly assist homeowners, estates, landowners and businesses with tree management following signs of disease, fungal activity or structural decline.

We work across:

• Hexham

• Corbridge

• Morpeth

• Newcastle

• Northumberland

• Cumbria

• The Scottish Borders

• The wider North East

If you’re concerned about the condition of a tree on your property, our team can help advise on the next steps and any recommended tree works following professional assessment.