New figures released today by Government show the scale of the UK’s reliance on cheap tree imports, putting the nation’s woods and trees at serious risk, warns the Woodland Trust.

The statistics, which reveal a near doubling in the value of tree imports since 2016, come a day after the Forestry Commission announced that a new tree disease - Phytophthora pluvialis- has been found in Cornwall, the first time it has been identified in Europe.

Figures show the total value of imported trees rose from £52 million in 2016 to £100 million in 2020, a 92% increase. Imports of outdoor plants, which are often alternate hosts for tree diseases, have also significantly increased from a low point of £19 million in the 1990s to £90 million in 2020.

The country’s increased reliance on imported trees has led to at least 20 serious tree pests and diseases being inadvertently imported into the UK since 1990, resulting in the loss of tens of millions of trees.

Nick Phillips, principal policy advocate for the Woodland Trust warned:

“It is not yet known how Phytophthora pluvialis arrived in Cornwall, but yesterday’s discovery is a reminder of the vulnerability of the UK’s trees to deadly pests and disease. This news, coupled with today’s figures revealing our dependency on cheap tree imports, must serve as a wake up call for tough new Government policy or risk losing tens of millions more trees.”

More than 100 million ash trees are expected to be lost to ash dieback at a cost of over £15 billion. This comes at a high price for nature too, with more than 900 species found on ash trees - 40 of which cannot be found elsewhere.

Mr Phillips continues:

“We know current policy isn’t working. In 2019 alone, oak processionary moth – which not only damages oak trees but is harmful to human health – was missed and imported more than 70 times into the UK!”

The charity warns that without tough new biosecurity policy, the Government also risks jeopardising its own targets of reaching net zero carbon by 2050 given tree planting is an integral part of its plans. Since leaving the EU, the Government has been drawing up new biosecurity legislation which is currently out for public consultation.

Mr Phillips warned:

“Our trees and woods face a growing threat from imported pests and diseases. Whole ecosystems are in the firing line unless the Government gets serious about biosecurity.

We need investment now in UK nurseries to enable them to grow the trees required for government tree planting targets and avoiding importing more pests and diseases.

“We need millions of new trees to help tackle climate change. This is hard enough, but by importing diseases that attack existing trees, we're making this challenge even harder and damaging important habitats in the process.”

The charity today launched a campaign to encourage the public to respond to the Government’s Plant Biosecurity Strategy consultation before it closes on November 30. Councils and private landowners face huge financial burdens of managing pests and diseases.

Mr Phillips adds:

“If more diseases took hold, landowners would be expected to foot the bill of managing or removing affected trees. We are already aware of the financial burden on landowners of dealing with ash dieback.”

There are at least 127 tree pests and diseases that are considered high risk to the UK. If imported into Britain, 47 of these could cost over £1 billion each to tackle and wipe out millions of trees.

In order to ensure that the trees that the Woodland Trust plant and sell are not imported, the charity established its own assurance scheme, known as UK & Ireland Sourced and Grown (UKISG).

This enables the Trust to work with UK nurseries to ensure a secure supply of trees that have been produced within the UK and Ireland (required for planting projects in Northern Ireland). The charity now urges Government and others to specify UKISG trees to help reduce the risk of importing new pests and diseases.

To take part in the consultation to demand more robust policy to protect the UK’s trees and woods, visit


Other key stats from today’s report:

  • Imports of outdoor plants, which are often alternate hosts for tree diseases, significantly increased from a low point of £19 million in the 1990s to £90 million in 2020.
  • In 2020, 344,000 tonnes of plants were imported - broadly consistent with the level from 2016.
  • By value, 83% of plants and planting material imported were from the EU, and 17% from the rest of the world.
  • In 2020/21, over 2,800 consignments of controlled material were notified to the Forestry Commission.

Case study

Oak Processionary Moth – a cautionary tale

The risks and consequent impacts from imports is exemplified by oak processionary moth. The caterpillars can defoliate oak trees, but most serious is the severe allergic reaction that contact with their hairs can cause in people and animals.

The UK continued to import oak, and inadvertently this pest, many times, with 1.1 million oak trees imported between 2013 and 2015. A nest was even discovered at the Chelsea Flower Show in 2016, and the moth is now widespread throughout London.  

Despite its known impact, considerable financial investment to manage this pest, as well as new legislation, the pest was once again imported in 2018/19, this time to more than 70 sites across the UK, from southern England to northern Scotland. Most of these trees were traced by plant health authorities and destroyed, but some were not.  

In 2019 alone the pest was transported into the UK at least 70 times. For such a well-known pest to be repeatedly imported demonstrates that border controls for plant pests and diseases (particularly those that are hard to identify) were not sufficient to keep out known threats, let alone unknown pests and diseases. This is particularly concerning because oak is a native species and could be grown within UK tree nurseries if investment was made in the production process. 

Notes to editors

For further information contact or, or phone 07977 184022.

The Woodland Trust is the largest woodland conservation charity in the UK. It has over 500,000 supporters.

The Trust has three key aims:

  1. protect ancient woodland which is rare, unique and irreplaceable
  2. restoration of damaged ancient woodland, bringing precious pieces of our natural history back to life
  3. plant native trees and woods with the aim of creating resilient landscapes for people and wildlife.

Established in 1972, the Woodland Trust now has over 1,000 sites in its care covering over 29,000 hectares. Access to its woods is free.


Plant Health – international trade and controlled consignments, 2016-2020, published by Department for Environment, Food and Rural Affairs

Agriculture in the United Kingdom 2020 Produced by: Department for Environment, Food and Rural Affairs (see page 75)