Oaks face 'slow burn' disaster
British oaks are facing multiple threats which could spell “disaster” for the country’s most important tree and the wider natural world, experts warn.The head of the Action Oak partnership of charities, landowners, research organisations and government bodies, says Britain must pay attention to the “warning signs” about the state of oaks, as the organisation releases a new report on the situation.Action Oak’s director Annabel Narayanan said the emblematic trees were facing a litany of pressures including acute oak decline which can kill a tree in three to six years and “we cannot allow what has happened with Dutch elm disease and ash dieback to happen” to oaks.StrippingBritain’s two native oak species, sessile oaks and pedunculate oaks, support more wildlife than any other native tree, playing host to more than 2,300 species, including 326 species that depend entirely on them for their survival.The country’s 170 million oak trees also store carbon, provide an important hardwood resource and are a key natural icon in British culture.Britain and some of the north of Ireland has more than 250,000 hectares (600,000 acres) of oak woodlands, much of it in England, as well as in hedgerows, parkland and standing sentinel in fields as remnants of old hedges and wood pasture.Hundreds of thousands of oaks are found in London, while tens of thousands grow in cities such as Belfast and Cardiff.But, a new report from Action Oak warns, the country’s oaks are facing pressures from climate change bringing higher temperatures and extremes such as drought, diseases and pests including invasive and non-native species, damage from deer browsing and grey squirrels bark stripping.WildfiresSome woodlands are also under threat from infrastructure, housing and business developments, with large areas of oak woodlands set to be destroyed by the HS2 rail route.The most prominent threat is acute oak decline, an interaction of several native bacteria and a native beetle, against a backdrop of environmental stress such as drought.The condition, which can be seen with weeping lesions and cracks in the bark with dark fluid seeping out, can kill trees that would live for a thousand years in a handful of years making it a “serious condition that threatens the long term resilience” of oaks, says chief plant health officer Nicola Spence.As of 2023, there were 394 sites recorded with acute oak decline. While oaks appear to cope relatively well under climate change scenarios as a species, research suggests, individual trees and woodlands may be stressed by drought – making them susceptible to disease – while rising temperatures will reduce growth and increase the risk of wildfires, the report said.WildlifeOther threats include oak powdery mildew, the knopper gall wasp which was introduced to Britain in the 1960s and the oak processionary moth which was introduced into the UK about 20 years ago and has spread through London and the South East. And new threats such as the oak lace bug could be coming to the UK, the report says.
