Staving off the threat to forests from strange diseases and climate change

It was a significantly more virulent strain than one which had been recorded a few decades earlier and as it spread across the country, it cut a devastating path.

Reacting like a falling row of dominoes, as the outbreak spread from the South to the North and from east to west, it was only when people began to notice chainsaws being taken to tree-lined avenues that, it stopped being just a concern of conservationists.

Dutch elm disease became front page news and such was its notoriety there was even a Trivial Pursuits question about it. By the 1990s, 25m of Britain’s 30m mature elms had been killed by the fungi. The worst case scenario had been realised, but according to those responsible for monitoring the threat of alien diseases, those figures could yet be dwarfed by a new set of outbreaks.

“I recently saw a timeline of different diseases and it’s fair to say they have increased dramatically over the last few years,” says Nigel Rylance, planning forester for the Forestry Commission in the North York Moors. “It’s partly due to the rise in world trade which means we are importing more goods from more places around the globe and that brings its own risks. Climate change also plays a part and the real problem is that once these diseases are here, there’s very little you can do to get rid of them.

“The only thing you can do is be vigilant and once you spot a diseased tree make sure the fungi doesn’t spread through things like controlled felling.”

Elsewhere, experts are keeping a close watch on the movements of the eight-toothed European spruce bark beetle. The bug, described as the most aggressive in Europe, has yet to arrive in Britain and in Yorkshire it’s two diseases with less obviously worrying names which are the cause of most concern.

A fungus known as phytophthora ramorum, named after the Greek for plant destroyer, and another called red band needle blight have the potential to wreak havoc across the county’s woodland.

The former caused widespread damage in California in the 1990s and was first found in the UK 10 years ago. While its main focus is rhododendrons, it also attacks trees like beech and larch.

The latter disease causes the needles of Corsican and Scots Pine to fall off and year on year weakens the tree until it eventually dies.

The Forestry Commission, with the support of Defra, has already set up the Biosecurity Programme Board to look at how best to protect the nation’s forests and 
a blueprint being drawn up by Nigel could prove an integral part of the plans to protect the country’s woodland for future generations.

“There is very little we can do about preventing the outbreak of new diseases,” he says. “But what we can do is identify the species most likely to be at risk and keep a close eye on them. It’s also about identifying other species we perhaps should be planting which may well be more resilient in the future.”

It’s not just the threat of alien invaders. For the last few months Nigel has been sitting in front of a computer, using a state-of-the-art software, alongside aerial photographs, wildlife and archaeological records, and the latest thinking on Yorkshire’s future climate to pull together a 50-year plan which will ensure Broxa Forest on the North York Moors can flourish in the second half of the century.

“This isn’t an exact science, but we do have projections of what kind of scenarios we are likely to face in the forest between 2050 and 2080,” he says. “We know, for example, that in general we will have more drought-like conditions.

“I know when I say that after the weeks of rain we have had recently that some people will roll their eyes, but that’s the difference between bouts of extreme weather and climate.

“In those drier conditions we know that larch struggle and at some point their numbers will drop off a cliff.

“We need species that are more resilient and before we hit crisis point we need to be looking at planting trees like the Macedonian pine which are more suited to those conditions.”

Broxa’s ancient woodland status means it dates back to at least the 1600s, but like many areas it was heavily planted with 
conifers following the Second World War to ensure Britain wouldn’t be reliant solely on imports for wood.

Many would like to see them removed and replaced with 
native species, but as anyone 
who has worked in forest management knows for every action there is often an unintended reaction by the flora, fauna and wildlife.

“Broxa forest stretches across 750 hectares, which is only about five per cent of the total land the Forestry Commission looks after on the North York Moors,” says Nigel.

“It might not be the biggest forest, but it is a really complex place and everything we do potentially has a knock on effect.

“Our aim is to restore part of the area to ancient woodland, which means removing some of the conifer, but if we are going to do that we really need to improve the access and that in itself brings it’s own problems.

“The River Derwent runs through Broxa which is home to the white-clawed crayfish, otters and kingfishers. Clearly we don’t want to disturb those populations or do anything which might effect the quality of the water. We are currently talking with the North York Moors National Park Authority, but before we push ahead with anything we have to be sure that it won’t have an adverse knock-on effect elsewhere in the forest.”

Broxa has been used extensively for woodland research and not just because its steep gills, open heathland and mix of tree species mean that it has a variety of habitats. This small corner of Yorkshire also boasts 30 scheduled ancient monuments and almost 200 historic features, including Bronze Age dyke networks, medieval quarries and 18th-century boundary stone markers.

“Broxa really does have everything and if we can get the plan right here, it will be really useful in ensuring we can get it right elsewhere,” says Nigel. “Our own staff have a vast resources of knowledge built up over many years of working in the area, but we are also incredibly lucky in that there are lots of other people who want to get involved.

“We have experts in archaeology, in wildlife and plants who all feel a sense of ownership of the place. If they come across something unusual or think there’s something we should know about, they will give us a call and their ideas and observations will ultimately all feed into the blueprint.

“This isn’t just about the Forestry Commission it’s about everyone who uses and enjoys the woodland.”

Ultimately, the plans being drawn up by Nigel and his team are also designed to protect the future of the area’s timber industry. Of the £4m made by the Forestry Commission in the area, £3.5m is generated from the industry.

“Conifers may be thought of by some as a bit of a blot on the landscape, but they are incredibly important and will become even more so as people switch to more sustainable fuel,” he says.

“It’s always easy to say if we could wind back 50 years we would have done things differently, but we have to work with what we’ve got.

“Like many forests up and down the country, Broxa has to serve a multitude of needs. It’s there to give the public access to the great outdoors, it’s there to be a habitat for wildlife and it is also there to make money so we can reinvest in protecting these forests in the future. The timber we produce is all part and parcel of that.

“Forest management is always a juggling act, but it definitely makes life interesting,” said Nigel.

The vital part forests play

Only 12 per cent of the UK is woodland, compared to an 
average of 44 per cent 
in other parts of 
Europe.

There are about 50 species of native trees and shrubs in the UK.

In the last 100 years, 46 broad-leaved woodland species have become extinct in the UK.

In 1980, native species accounted for only five per cent of trees planted in the UK. By 2000, this figure had risen to more than 40 per cent.

Between 2010 and 2011 8,000 hectares of new woodland was created in the UK.

The country’s forests help to counter carbon dioxide emissions by removing more than 10m tonnes of carbon dioxide from the atmosphere each year.