Ash dieback - the next branch of litigation?

  • Étude de marché 18 septembre 2023 18 septembre 2023
  • Royaume-Uni et Europe

  • Casualty claims

According to figures published by the UK government, it is estimated that there are more than 125 million Ash trees in UK woodlands and between 27 and 60 million Ash trees in other areas of the country. It is the second most abundant tree species and plays an important role in the country’s ecosystem.


Ash dieback, caused by the fungus “Hymenoscyphus fraxineus”, was first recorded in the UK in 2012. It originated in Asia and has caused widespread destruction of Ash trees across Europe. Trees are infected with the fungus via airborne spores produced from fruit bodies. These fruit bodies tend to grow on infected fallen leaves at the base of the tree trunk. The spores infect the Ash tree leaves resulting in the fungus growing into the wood. This can create a cycle of infection, ultimately leading to the destruction of the tree.

It is thought that at least 80% of all Ash trees in the UK are infected with the fungus. The symptoms of this include, but are not limited to, the presence of wilted or spotted leaves, and significant leaf loss at the crown. Many Ash trees border public highways and open spaces, and falling trees and branches could cause serious personal injury or property damage. This means that it is a significant risk which needs to be considered by insurers and brokers.

Ash dieback also presents significant challenges for transport operators responsible for maintaining the UK’s railway lines. There are many Ash trees straddling railway lines across the country. Transport operators and local authorities are already contending with the increasing cost of claims resulting from Japanese Knotweed, which is prevalent across many of the country’s railway lines, and operators’ resources for dealing with ecological challenges such as these are already stretched.

As is the case with Japanese Knotweed, the problem is of particular concern to transport operators in Wales. According to Network Rail, there is more than 2,700 miles of railway in the “Wales & Western region” of the network. If Ash dieback is not tackled, many people living in areas bordering this section of the railway network will be put at risk of injury or damage to their property. There is also likely to be increased disruption as more railway lines must be cleared of debris from fallen Ash trees.

Taking action now

Landowners responsible for Ash trees on their land, including transport operators, have a duty of care for those present on the land not to cause damage to their property and/or cause them to suffer personal injury. For this reason, the spread of Ash dieback has the potential to give rise to litigation in the future. It is important that transport operators take action now to ensure they minimise disruption to their services and minimise the prospect of claims in the future.

To minimise exposure to this risk, it is recommended that transport operators owning land containing Ash trees take the following steps:

  1. A systematic survey should be undertaken to the Ash trees for which landowners have responsibility. Transport operators should consider encompassing surveys of Ash trees into any inspections of their network, such as when clearing leaves from the tracks or during track maintenance.
  2. The action to be taken to deal with infected Ash trees should be judged on a case-by-case basis based on the severity of the infection, the amenity value of the tree, and the complexity of its removal. Infected trees should not necessarily be felled. It is thought that a small percentage of Ash trees could be resistant to the disease and removing them may result in the species becoming extinct. 
  3. Action should be taken to remove Ash leaf litter from the ground around the trees in Autumn and winter. The spores carrying the fungus spread to the tree wood via infected leaves and by removing them, its lifecycle is disrupted. It is recommended that the fallen Ash leaves are burned.
  4. If a transport operator is notified of a potentially hazardous Ash tree, steps should be taken as soon as possible to ensure any risk is minimised. Landowners have a duty of care to those present on the land and those within its vicinity not to cause damage or injury. Liability will attach to transport operators who are on actual or constructive notice of such risks but fail to mitigate them within a reasonable period of time.


With the ever-decreasing profit margins in dealing with personal injury claims, claimant solicitors are constantly looking for other sources of work. Ten years ago, it would not have been foreseeable that Japanese Knotweed would have attracted the volume of litigation it does now. It is important that Ash dieback is managed carefully, not only to ensure the proper running of the transport network and to ensure good service for passengers, but also to avoid this becoming a future problem for claimant solicitors to exploit.


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