Tree Health, Pests & Diseases

Information about tree health, pests and diseases

When a tree health assessment may be useful

A tree health assessment can be useful when a tree appears to be in decline, has visible fungal growth, shows signs of damage or is located close to people, buildings, roads, boundaries or public areas.

It may be recommended where you notice:

• Fungal brackets or fruiting bodies on the trunk, branches or around the base
• Deadwood, dieback or thinning in the crown
• Cracks, splits or weak branch unions
• Sudden leaf loss, poor growth or discoloured foliage
• Root plate movement or signs of decay around the base
• Pest activity, cavities, wounds or areas of damaged bark

Decay in trees

Decay in trees can begin above or below ground.

Above ground, fungal fruiting bodies are often found on stems or branches, especially where the tree has been damaged or where dieback has started. This decay can then move downwards towards the roots.

Below ground, decay can begin in individual roots or within the central root plate. Once established, it may move upwards into the buttresses, stem and crown of the tree.

The level of risk depends on the type of decay, the tree species, the amount of sound wood remaining, the tree’s location and the likelihood of failure causing harm.

Common fungi found on trees

There are several fungi commonly found on trees. Some may indicate serious decay, while others need to be assessed in context before deciding what action is required.

Common examples include:

• Armillaria mellea, honey fungus – often found around the base of trees and roots. Depending on severity, it can be serious and may lead to instability or failure.
• Fomes fomentarius, hoof fungus – often associated with beech and silver birch, affecting stems and larger branches.
• Ganoderma applanatum, artist’s fungus – commonly found around the base or buttress area and can affect the strength of the tree over time.
• Inonotus hispidus, velvet fungus – commonly found on ash and plane trees, but can also affect sycamore, apple, sorbus and walnut.
• Kretzschmaria deusta, previously known as Ustulina deusta – often found on beech, maples and lime, usually around the lower buttresses and roots.
• Meripilus giganteus, giant polypore – often associated with beech trees and root decay.
• Polyporus squamosus, saddle fungus – commonly found on broadleaved trees such as sycamore, horse chestnut, lime and beech.

Why professional diagnosis matters

Fungal decay does not always mean a tree has to be removed. Some trees can stand for many years with decay present, while others may become unstable with very few visible warning signs.

A professional assessment helps identify the likely issue, the level of risk and whether the tree should be monitored, pruned, reduced, supported, dismantled or removed.

Where a tree is close to a building, road, footpath, public area or other target, it is especially important to understand whether the defect presents a safety risk.

Tree health and safety recommendations

Depending on the findings, recommendations may include monitoring the tree, removing deadwood, reducing selected limbs, carrying out a crown reduction, improving clearance with crown lifting, or removing the tree safely where the risk cannot be managed.

For trees affected by serious decay, poor structure or significant instability, controlled sectional dismantling or felling may be required.

Professional pest and disease diagnosis by Norfolk Trees

Norfolk Trees was established in 2002 by Ashley Barnes and operates throughout Norfolk and East Anglia. Our tree surgeons are fully qualified for the work they undertake and have experience across all aspects of tree care.

Our work includes dismantling, felling, crown lifting, crown reductions, dead wood removal, formative pruning, tree surveys to BS5837, tree hazard reports, pest and disease diagnosis, bat inspections, stump grinding or treating and tree planting.

Clients can be confident in the quality of our work. Norfolk Trees holds £10,000,000 public liability insurance and all work is carried out to BS3998:2010.

In addition to domestic tree work, we undertake commercial work for local authorities, parish councils and other organisations, including the Borough Council of King’s Lynn and West Norfolk, Breckland Council, Serco, South Norfolk Council, Broadland Council, NCC Highways, KierMG and Anglian Water, along with numerous other clients.

We are also approved by the Norfolk County Council, and are CHAS Accredited through the Contractors Health and Safety Assessment Scheme.