Trees are at the heart of the British landscape. From the oak woodlands of the South West to the beautiful native Scot’s pines of the Highlands, they shape our scenery, support wildlife, and help combat climate change. Yet these vital ecosystems face growing threats, from pests, diseases, and invasive species that can spread rapidly and cause lasting damage.
This is why biosecurity matters.
What Is Biosecurity?
Biosecurity means taking measures to prevent the introduction and spread of harmful organisms,such as pests, pathogens, or invasive plants, that threaten our environment, agriculture, and economy. In the UK, it plays a critical role in protecting our trees, forests, and Sites of Special Scientific Interest (SSSIs), many of which contain irreplaceable habitats.
A Growing Threat to Tree Health
In recent decades, the UK has seen a sharp rise in tree pests and diseases, many arriving through international trade and travel. Ash dieback has already killed millions of ash trees across the country, altering landscapes and ecosystems for generations. The oak processionary moth weakens native oaks and poses health risks to people and animals. Meanwhile, pathogens such as Phytophthora ramorum continue to devastate larch and other species.
Once established, these threats are extremely difficult to eradicate. Trees take years to mature, and their loss affects not only the landscape but also the wildlife that depend on them.
Why Our Vulnerable Habitats Need Protection
Britain’s SSSIs, National Nature Reserves, and ancient woodlands are among our most treasured environments. Many of these areas support rare plant and animal species that rely on healthy trees and undisturbed woodland ecosystems.
However, their ecological value also makes them fragile. Diseases can spread quickly in these connected habitats, and invasive species can permanently alter their structure and diversity. Rhododendron ponticum, for example, forms dense thickets that shade out native plants and change soil chemistry, while pests introduced through imported plants or timber can silently spread across woodland boundaries before being detected.
Protecting these sites is not only about preserving beauty or heritage, it’s about safeguarding biodiversity and ensuring ecosystems remain resilient in the face of climate change.
The Wider Impact
Tree and habitat health are deeply linked to the UK’s wider environmental and economic wellbeing:
- Biodiversity: Healthy trees provide nesting, feeding, and shelter for countless species. Their decline can trigger cascading losses in wildlife.
- Climate resilience: Trees store carbon, reduce flooding, and moderate temperatures, services we lose when woodlands are degraded.
- Cultural value: Iconic species such as ash, oak, and beech are part of Britain’s identity. Their loss reshapes our countryside and communities.
The cost of poor biosecurity is high, both environmentally and financially. Prevention is always more effective and far less expensive than dealing with outbreaks after they occur.
Strengthening the UK’s Biosecurity
The UK government, through DEFRA, the Forestry Commission, and the Animal and Plant Health Agency (APHA), leads on national biosecurity measures. These include import checks, surveillance programmes, and rapid-response teams to manage emerging threats. Initiatives such as the Tree Health Resilience Strategy aim to improve early detection, promote research, and encourage better planting practices.
But the success of biosecurity depends on shared responsibility. Everyone who works with, manages, or enjoys the countryside has a part to play.
Simple Actions That You Can Do That Will Make a Difference
- Clean boots, tools, and vehicles before and after visiting woodlands to avoid spreading
soil-borne pathogens. - Source trees and plants responsibly, using UK-grown stock wherever possible.
- Be vigilant, report unusual signs of pests or disease using tools like TreeAlert or through
local authorities. - Respect site restrictions and follow advice when visiting sensitive habitats or SSSIs.
- Learn and share, raising awareness of biosecurity helps build a culture of care and
prevention.
Biodiversity Goals: Looking Ahead
The UK is expanding its tree cover to meet ambitious climate and biodiversity goals. However, as we plant more trees, it is crucial that new woodlands are created with resilience in mind. This means diversifying species, ensuring planting material is pest-free, and monitoring tree health throughout the supply chain.
Good biosecurity is not about limiting access or discouraging planting, it’s about protecting what we value most. By embedding biosecurity into everyday decisions, from garden centres to national policy, we can ensure our woodlands and SSSIs remain healthy and thriving.
Biosecurity may sound technical, but its purpose is simple: to protect life. Every tree in a hedgerow, park, or forest plays a role in sustaining the landscapes and wildlife that define Britain. The threats they face are real, but so is our ability to prevent them.
Through awareness, responsibility, and cooperation, we can keep our trees, the special places they create, safe for future generations.