Will 2019 be make or break time for forests?

Woodlands are disappearing at a faster rate than ever before because of tree disease, writes Martin Hesp

IN some corners of the West Country you’d hardly know there was a war on – in other parts, you will see the sylvan version of Armageddon. Tree disease is sweeping the UK and, in some of the worst-hit zones, massive clear-fell operations have been executed as a way of dealing with the problem.

For example, in the north-facing combes of the Brendon Hills, in Somerset, hardly a tree is left standing in areas which – just two years ago – were covered in thousands of acres of forest.

The steep, 1,000ft slopes around the hamlet of Comberow looked like a West Country version of Canada just 18 months ago; now, they’ve been laid bare, mainly because of tree disease creeping into the forests.

One forestry owner in the area said he had been the first person in the UK to detect Phytophthora ramorum in the open countryside, at a site in the Brendons more than a decade-and-a-half ago. The disease is more commonly known as ‘sudden oak death’ because different strains of the pathogen have been causing havoc among North American native oak and tan oak species for many years.

On this side of the Atlantic, we can all give thanks that it does not affect our native oaks, but it has been sweeping through other tree species, including larch.

Thanks to that fungus-like pathogen, ramorum disease has hit these forests big time. Indeed, they are forests no more.

Vast swathes of larches on the steep-sided valleys have been felled and turned to mincemeat.

Not long ago, walking on the top of the Brendon escarpment near the upper end of the forests, I came across some men operating gigantic mulching machines – they were passing huge tree trunks into a maw of noisy, scrunching blades. The fine wood chips coming out the other end were blasted into the sealed trailer on an articulated lorry.

“Thank God for wood-chip boilers,” said one of the men. “The infected timber can be used to make pel- lets which incinerated.

“Otherwise, it has to go through an expensive treatment process.”

The Forestry Commission website says the disease is spread by “rain splashing on infected needles and leaves; wind, wind-borne mists and water courses; movement of infected plants; movement of contaminated soil, leaves or needles from infected trees and shrubs stuck to footwear, clothing, timber, vehicles and equipment”.

The website also states: “The main precaution is for everyone to ensure that footwear is first cleaned of all soil, needles and plant debris and

are

going

to

be then disinfected before entering or leaving a control site.” None of the ex-forests I walk through had any signs to tell you this but, if you look at the Forestry Commission’s latest UK map pinpointing ramorum outbreaks, you see that the West Country peninsula is by far the worst hit area, along with South Wales.

Indeed, large swathes of eastern England remain untouched by the disease, but west of the River Parrett you are unlikely to be more than ten miles from an outbreak.

“The damage to our trees, woods and forests from insect pests and organisms such as bacteria and fungi is significant,” said a spokesman from Defra.

“The rapid increase in movements of goods and people between countries has increased the risk of spreading pests and diseases.

“They can travel hidden in plants, plant products, packaging, wood, vehicles and holidaymakers’ luggage – even in the soil carried on shoes.

“Some of these pests and diseases do little harm in their native environments, where predators, environmental factors and co-evolution with their host plants keep them in check.

“However, they can cause significant damage to trees and plants in other countries where those limiting factors are not present.”

Brexit may or may not sort out the UK’s political and economic relationship with the EU and other areas of the world, but it seems that nature has other ideas when it comes to international borders. The Forestry Commission lists no fewer than 22 tree diseases that are currently threatening woodlands around the UK. They range from sudden oak death to oak wilt, from horse chestnut bleeding canker to sweet chestnut blight.

It also lists 18 tree pests, such as the Asian longhorn beetle, the elm zigzag sawfly, the oak processionary moth and the Siberian coniferous silk moth.

In terms of human migration, there is an issue that can, presumably, be negotiated and sorted – but when it comes to harmful pathogens coming in from overseas, the nation is under siege.

The Forestry Commission lists 22 tree diseases that are

threatening woodlands in the UK

Larch trees are among those affected by disease, changing the face of the landscape