Acorns and the Oak Trees they eventually grow into are iconic images associated in the English mind with nature and national image. The Woodland Trust has issued a warning that they may be under threat like never before due to climate change.
Last year was a ‘mast’ year, meaning more acorns than usual were produced, this is part of a natural ‘boom and bust’ cycle well known to scientists. Drawing on evidence from their Nature's Calendar Survey The Woodland Trust report data suggesting the acorn crop this year is the worst for twenty years.
Is this cause for concern? In an article published on their website Lorienne Whittle suggests that it is, she writes: ‘Whilst the lack of acorns this autumn is in part due to a natural cycle, unfortunately our cherished oak trees are facing a myriad of threats. These are not only causing harm to individual trees but will also impact future generations of oak if less acorns are produced’.
Nature's Calendar is a long running citizen science project supported by the Woodland Trust containing 2.9 million records going back to the eighteenth century, the data gathered is used by experts worldwide to track the effect of climate and weather on wildlife.
Oak trees flower from April to May and the number of acorns produced is influenced by weather conditions. This spring saw the UK experience unusually late frosts, this can damage oak flowers, May this year was also, according to Met Office data, the wettest since 1862. The summer that followed was unusually dry with lower-than-average rainfall, if a tree is suffering water stress it will produce fewer acorns.
A changing climate in the UK featuring drier summers will have a damaging impact on oak trees, with many possibly succumbing to ‘oak decline’, a disease that occurs when individual trees are under stress and can make them more susceptible to pests and disease. As a result, a healthy tree could die off in as little as five years.
Action is needed to protect these iconic trees for future generations and to support their continued role as part of our ecosystem. Lorienne Whittle writes ‘If we want future generations to revere oak trees in the way we have for so many centuries, we need to support our native oak trees’.
The decline of oak trees in the UK feeds into global concerns about deforestation, since 1990 420 million hectares of tree cover have been lost through human activity such as farming and logging. This contributes 4.8 million tonnes of carbon dioxide to the atmosphere every year. At the COP26 summit more than 100 countries pledged to end deforestation by 2030, but matching actions to words has proved problematic.
INPE, the space research agency for Brazil, one of the countries that signed the COP26 pledge, published data in November showing that deforestation in the Amazon was at its highest level for 15 years, with 13,235 sq km being lost in 2020/21, the largest amount since 2006.
Last year Greenpeace and other campaign groups identified links between UK supermarkets and restaurants and deforestation in Brazil and other South American countries. This is something the companies concerned have taken pains to keep from their customers, many of whom think they are buying environmentally friendly products [5].
Speaking in November 2020 Chiara Vitali of Greenpeace UK told the BBC Radio One programme Newsbeat "Trees are basically one of our best defences against climate change, leaving them standing can really help reverse the effects of climate change and draw carbon back out of the atmosphere”.
Adding that when trees are “destroyed” it “makes climate change worse”.
The UK government has announced plans to plant 260,000 trees and to restore declining biodiversity described by Sir William Worsley, chair of the Forestry Commission as “inspiring initiatives that will help to stem the tide of biodiversity loss and promote resilient tree growth and management across the UK, whilst helping to futureproof our natural world amidst a changing climate”.
For all their size and majesty oak trees are only a small part of the wider ecosystem, their image though has a powerful resonance in the British imagination. Perhaps seeing them under threat will help to raise awareness of the much wider threat to human and animal life presented by climate change and spur government and individuals to act instead of making empty promises.
Scientific experts have though expressed concerns that the UK is not doing enough to meet the commitments it made at the COP26 summit and may even contribute to a disastrous rise in global temperatures if it does not change course.