State of the UK’s Oaks

Oak trees are a vital part of the UK’s biodiversity, cultural heritage and economy, supporting more than 2,300 species and contributing environmental, social and economic benefits estimated at £0.7 billion each year.

Action Oak's new State of the UK's Oaks report, funded by Defra, sets out the current state of UK oaks by bringing together key information, monitoring data and a review of existing work, while identifying important evidence gaps. Find out more and download the summary analysis 2026 report below.

Oak trees (Quercus spp.) are among the most iconic and ecologically significant tree species in the UK and yet relatively little is known about them, the threats they are facing, and how they are faring in the face of multiple stressors.

Our new State of the UK's Oaks report provides a summary of what is known about the current state of the UK’s oak trees. It presents evidence on the importance and value of the UK’s oak trees and woodlands, threats to them, and their current extent, condition and diversity. The document also identifies future needs to help safeguard their future.

Action Oak’s values guide our work to be collaborative, innovative, and committed to our evidence-based scientific research.

Our new State of the UK's Oaks report sets out the current state of UK oaks by bringing together key information, monitoring data and a review of existing work, while identifying important evidence gaps. You can read the full report here.

Download the summary report

Action Oak's major new report reveals the UK’s most iconic tree is facing a convergence of threats unseen in modern times, with scientists warning that without urgent action the UK risks losing oak as a defining feature of its landscape.

You can read the full report here

  • “The report’s findings are a stark warning. What we are seeing with oak is not a single threat, but a convergence of pressures acting at the same time. Ageing trees, failed regeneration, climate stress, pests and disease. Each one on its own might be manageable, but together they are pushing the UK’s most important tree towards a tipping point, this could be a slow-burn ecological disaster.”

    – Annabel Narayanan, Director, Action Oak

  • “Oak supports more biodiversity than any other native tree in Britain and stores around 31 million tonnes of carbon. When a species that underpins ecosystems, climate resilience and cultural identity starts to fail, the consequences are national, not local. Long term surveys show fewer young oaks establishing, while mature trees dominate the landscape. Without regeneration, today’s ageing oak population becomes tomorrow’s ecological cliff edge.”

    – Geraint Richards, Head Forester to the King and Duchy of Cornwall

  • “The UK holds Europe’s greatest population of ancient oak and they are disappearing. The loss of ancient and veteran oaks doesn’t just reduce species numbers; it dismantles whole ecological systems that have taken centuries to form. These habitats cannot be replaced by planting young trees, they are ecologically rare and increasingly vulnerable. Once an ancient oak is gone, it is gone for good, you cannot replace centuries of habitat and they need our protection.”

    – Tony Kirkham MBE VMH, former Head of Arboretum, Gardens & Horticulture Services, Royal Botanic Gardens, Kew

  • “Oak leaf flushing now happens up to two weeks earlier than it did at the start of the century. That shift may seem small, but it signals deeper changes in our climate and, in turn, how trees respond to pests and extreme weather. Oak as a species is relatively resilient to climate change, but that doesn’t protect individual trees. When stresses such as drought, soil degradation, disease and storm damage combine, those compound risks can overwhelm even resilient species.”

    – Kate Halsted, Climate Scientist and researcher

  • “Our oak trees are intimately woven into our natural landscapes, our economy and cultural heritage. They support over 2,300 other wildlife species, are hugely important for storing carbon and can produce high value timber. Yet less than 15% of oak timber used in the UK is domestically sourced. Pressures on our oaks from pests and diseases, climate change, browsing by deer and squirrel are increasing. Many of our oaks are in decline and we are not seeing enough young trees coming through to replace them. Protecting and restoring oak isn’t just about conserving an iconic tree – it’s about safeguarding biodiversity, climate resilience and meeting the needs of productive and resilient forestry.”

    – Lisa (Smith) Brooks, Chief Operating Officer of Forest Services, Forestry Commission

  • "Oak trees are a cornerstone of the UK’s landscapes, supporting a wide range of species and enriching our cultural and natural heritage. Yet our native oaks are increasingly under pressure, including from Acute Oak Decline – a complex and serious condition that threatens the long‑term resilience of this iconic species. The 'State of the UK’s Oaks' report provides an important evidence base to help us understand these challenges and focus our collective efforts to ensure that future generations continue to enjoy the immense environmental and societal benefits that healthy oak trees bring."

    – Nicola Spence, UK Chief Plant Health Officer

Could you be a citizen scientist and help us monitor our oaks?

Action Oak’s vision is for a UK where our native oak trees are protected and flourish, both now and in the future. Join us in taking action to protect our oaks.

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Action Oak brings together representatives from charities, landowners and government to develop a coordinated plan to identify and tackle issues threatening our native oak trees.

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Action Oak would like to extend thanks to all those who have contributed to this State of the UK’s Oaks report.