Why it’s important to purchase trees that are sourced and grown from the UK

Protection from exotic pests and diseases

Purchasing trees from the UK is among the simplest and most effective strategies to shield them from pests and diseases. When new species are introduced from abroad, our native trees lack natural defences against them, compounded by the absence of their natural predators. Consequently, pest and disease outbreaks can wreak havoc on our forests and woodlands.

The magnitude of this threat is underscored by the fact that nearly all native tree species in the UK have grappled with introduced pests or diseases over the past three decades. Exotic pests and diseases infiltrate the UK primarily through inadvertent movement within the trade of plants, timber, and wood products, hitching rides on intentionally imported goods. For instance, ash saplings carrying ash dieback were unwittingly circulated across Europe during the 2000s.

How do diseases get into the UK

The incidence of serious pest and disease introductions into the UK has surged since 1990, mirroring the rise in plant and tree imports from the EU and beyond.

Despite early signs of trouble with the oak processionary moth in northern Europe in the early 2000s, the UK continued to import oak, resulting in multiple inadvertent introductions of the moth since 2007, including a notable discovery at the Chelsea Flower Show in 2016. The moth has since proliferated throughout London.

Current border controls for plant pests and diseases fall short in preventing the entry of known threats, let alone unidentified ones, rendering detection virtually impossible.

What about climate change?

The anticipated depletion of trees caused by imported pests and diseases is staggering and poses a substantial obstacle in combating climate change. Meeting our climate targets necessitates the addition of at least 1.5 million hectares of woodland by 2050, presenting a daunting challenge just to maintain our current status quo. Should new pests or diseases infiltrate the UK, the endeavor to expand tree cover will become increasingly arduous and costly, requiring intensified efforts merely to prevent regression. The UK faces the grim prospect of losing millions of trees to exotic pests and diseases, exacerbating the urgency of proactive measures to safeguard our arboreal ecosystems.

How is nature affected?

The loss of millions of native trees to imported pests and diseases would profoundly affect the native wildlife dependent on these trees. Oak and ash, as pivotal species in woodland habitats, provide crucial support for numerous species. For instance, ash sustains 44 species that cannot thrive on other tree species, while oak supports 326 such species. Additionally, many other species rely on these trees in conjunction with others.

If ash and oak experience significant declines, the species depending on them would suffer as well. This decline in biodiversity could have extensive ramifications for nature, reverberating across ecosystems and posing significant ecological challenges.

The most straightforward approach to mitigate the risk of new pests and diseases entering the UK is to plant trees that have never ventured beyond our borders. Ideally, trees destined for planting in mainland Britain should originate and grow within the same region. This measure significantly diminishes the likelihood of pests and diseases infiltrating shipments of saplings or seeds imported from overseas. This principle extends to plants, including beloved horticultural varieties, as pests and diseases possess the potential to spread to diverse species. For instance, Xylella fastidiosa, a pathogen affecting olive trees, lavender, and rosemary plants, also poses a threat to certain broadleaf trees like oak, magnifying the peril to our native woodlands.