How to Create a Climate-Resilient Woodland in the UK

Mighty ash trees ravaged by dieback are now an all too familiar part of our landscape – the Woodland Trust estimates that 80% will eventually be affected by Hymenoscyphus fraxineus, a wind-borne fungal disease. One day, ash trees may be the stuff of memory – changing the country’s landscape beyond recognition. So how to tackle the loss of these trees and, with it, their timber crop? “It is increasingly challenging to find trees that don’t have some sort of pest or disease,” says Mark Townsend, head of woodland management and arboriculture at Savills. “We need to make sure there is variety in our planting.”

Ash dieback is just one of many diseases and pests threatening our native and woodland trees – at least 20 are new since 2000, according to the Woodland Trust. And climate change looks set to make the situation worse. Acute oak decline and the oak processionary moth are menacing our noblest species; phytophthora pathogens affect a wide range of trees, including oak, larch, juniper and chestnut; and cankers and blight also attack our chestnuts and oaks.

Thankfully, says Townsend, there is a solution. “On estates where we have a lot of ash that has been taken out, we have replanted with hornbeam, whitebeam, sycamore – a good replacement for ash, because of the wildlife that can live on both – beech, hazel, oak, hawthorn, blackthorn and holly,” he says. “You have your big tree species and your shrub layer, things like holly and hazel.”

What about the much-maligned conifers? “We try to introduce an element – up to 20% – as a lot of them are evergreen, and provide roosting and shelter in winter. The ‘broadleaf good, conifer bad’ approach needs to be banished – it is not that simple. If you prefer native species, you could plant Scots pine or juniper, or it might be Douglas fir, spruce or western red cedar if you want exotic species. Conifer is a good nurse crop, too, so you are using it to help the others grow up nice and straight.”

Conifers can also pay off in financial terms. “If you are growing at scale and have a conifer element, you might start to see a financial return in years 15-30,” Townsend explains. “With broadleaves, you wouldn’t be getting any firewood until years 30-40.”

Sourcing seed from a wider genetic pool can boost diversity and climate resilience. “If you want to go native, traditionally you would plant from your own geographic area because it protects your local genetics,” Townsend says. “There is a school of thought, however, that you should be planting seeds that are sourced from several degrees south of where you are.

“In Scotland, for instance, you might want to plant seeds from the south of England, then, in 100 years’ time, your trees will be better able to cope.” For southern England, it might even be best to get seed from the south of France to build up that genetic resilience.

Nature has great powers of recovery: one of the reasons there is so much ash in the south of England is that it grew quickly in the gaps caused by the storms that ravaged parts of the UK in October 1987, blowing down about 15 million trees. Some of our ash trees are up to 200 years old, and Forest Research, part of the Forestry Commission, encourages landowners to leave them standing unless there are public-safety concerns, in the hope that they may develop some resistance.

There is another glimmer of hope for the ash tree, too. As a result of dedicated breeding programmes, several disease-free varieties are now available. Our landscapes may once again be dotted with these magnificent trees in years to come.

More advice on managing England’s woodlands in a climate emergency and woodland tree health grants is available at gov.uk

Pictures from top: looking up into a canopy of oak (unsplash); the grounds of St George estate in the Channel Islands; a tree-lined pathway at St George; and a glimmer of hope for the ash tree (Getty)