As treescapes go, you can’t get much more special than Moor House National Nature Reserve in Upper Teesdale, Co Durham. It may be the only place in England where you can feel as if you’re walking through a vast sea of juniper. This rare species, one of only three native conifers in the UK, grows low and spreading across the hillside, with venerable specimens that must be two to three hundred years old.
How devastating, then, that this concentration of juniper is the latest victim of what seems to be a never-ending list of new pests and diseases threatening the UK’s trees. Phytophthora austrocedrae (P. austrocedrae) is a fungus-like pathogen that often kills its host. Until recently it was almost unknown here, but has recently been found causing die-back of juniper in Teesdale, and on specimens of cypress trees in Scotland.
There are only around 400 hectares (ha) of juniper woodland in Britain, most in Scotland; the site in Teesdale is the largest area in England. Juniper itself has declined in the last quarter of a century, especially in the uplands, yet it is of key importance for biodiversity, supporting a specialised group of insects, fungi and lichens.
As yet, nobody knows how the infection reached this remote location, though it is thought the disease is spread by water and contaminated soil and plant material. Natural England staff, and the Food and Environment Agency are looking at how best to deal with it, without spreading the disease further.
At Moor House, the juniper wood is just one element in a magical landscape. It is England’s largest National Nature Reserve, also designated as a SAC, and by UNESCO as a biosphere reserve. The waterfall at High Force tumbles over an outcrop of the Great Whin Sill, and unusual sugar limestone supports a rare array of arctic-alpine plants, like the spring gentian, found nowhere else in England.
In fact, the reserve is a bit like the land that time forgot, hosting plants that colonised the area after the last Ice Age and survive there still. The 8,800 ha reserve incorporates a huge range of rare habitats: limestone grassland, upland hay meadows, heaths and blanket bogs, as well as the juniper woodland.
Much studied, and now a leading site for research into the effects of climate change, this landscape is incredibly special. It is worrying that even somewhere so valued and well-cared for, and so remote, is not immune to the invasion of a potentially devastating disease.
In the State of the UK’s Forests report, published at the end of the last year, the Woodland Trust and others highlighted the challenges facing our woods and trees, and the need to build resilience. The number of new pests and diseases seems to be increasing, and researchers and policy makers recognise that this may be exacerbated by climate change. We have already seen the effects of Phytophthora ramorum, which has hit commercial stands of larch, concern is growing about Acute Oak Decline - affecting oaks across central England and Wales, and sweet chestnut blight has now been found in Britain.
We need the Government to take these threats seriously. Certainly, the development of a plant health strategy is a step forward, but there must be sufficient funding in future for research into new pests and diseases, and resources to tackle them. If the potential effect of this latest disease on a truly unique landscape is not a wake-up call, I don’t know what is.
Sian Atkinson, Conservation Communications & Evidence Adviser