In the autumn of 2012, when Ash Dieback was first found in the wild in the UK, Dr Anne Edwards, who also works at the John Innes Centre, took a piece of wood from a sick ash tree in Ashwellthorpe Lower Wood to the centre. Other scientists there took a DNA sample from it and confirmed that it contained the pathogen Chalara fraxinea. A cross-section of wood with Ash Dieback shows what resemble ink blots on top of the concentric rings. Windblown spores of Chalara fraxinea infect leaves. The fungus grows down the leaf stem and into the core of the tree. Trees with Chalara fraxinea are more susceptible to other pests and pathogens, such as Armillaria fungi or honey fungus.
Research into Ash Dieback aims to find out how the pathogen is getting into the trees. The work has been accelerated by the use of crowd sourcing, which enables people from around the world to make contributions. Whereas before Dan would have had to prepare a paper and wait for a conference, through crowd sourcing, or publishing results straight away, he receives feedback almost immediately. He is helping to build a map of the areas in the ash genome – the complete set of genes present in each cell of an organism – where susceptible trees differ from those that are resistant. Dan is a member of the Nornex Consortium, headed by Professor Allan Downie, leading the investigation into Ash Dieback, made up of various partners, which include the Sainsbury Laboratory, the universities of Edinburgh, York, Exeter and Copenhagen, Forest Research, the Food and Research Agency, the Genome Analysis Centre, and the Forest and Landscape Institute, Norway. Nornex Group scientists are working with Danish scientists who identified the so-called Tree 35, which has low susceptibility. If they can identify the unique genetic features that reduce its chance of being infected by Ash Dieback, it will help them to breed an ash resistant to Ash Dieback in Britain. Perhaps the tree contains an enzyme that inhibits the disease. Maybe its bark is thicker. They are trying to find the answers to these questions because Chalara fraxinea is such a virulent fungus.
Identifying resistant trees could speed up the process of replacing those ashes that will probably die of disease. In their search for sources of resistance, the task of scientists at the John Innes Centre and Sainsbury’s Laboratory is made harder by the fact that there is almost free movement of plants: our border controls expose our native plants to exotic diseases because security is less tight than it should be. Dan confirms that saplings are grown in Europe then brought to these islands, which makes it difficult to monitor their provenance.
Early in August, Dan and his colleagues release the ash game Fraxinus on Facebook. In its first six months it attracts an overwhelming number of players, who score points by putting together sequences of coloured leaves on their computer screens, matching them to genetic data that scientists working on Chalara fraxinea have found. Scientists may use the data the game produces to help analyse the susceptibility of a certain tree to the disease or to probe genomic DNA.
At the end of August 2013, Antony Milek, a student, sets up a vigil to guard an ash just over his garden fence in Kitson Hill Road, Mirfield, in West Yorkshire. It is in danger of being felled because the rest of the mature trees close to it, nearly thirty altogether, have gone: workmen believed that permission had been granted for the land to be sold to developers. He attracts the attention of the local papers, who report on his activities. Antony sits in the shade of the tree, which has been there all his life, at the bottom of his garden: as he is so close to it, the workmen cannot risk felling the tree. The land in question was once a refuge for birds and small mammals. The ash towers over the fence; it has two trunks, and appears to be in perfect health. A protection order should have been placed on it because Chalara fraxinea threatens ash trees.
On 5 June in Arkon, Ohio, a woman is arrested for sitting in an old ash tree that developers are waiting to chop down. This is the culmination of a week-long protest by local people and supporters who have occupied the tree in an attempt to persuade the local council and the land owners not to fell it. The ‘irony’, the local paper reports, is that it is only a matter of time before the Emerald Ash Borer, which has already eaten billions of America’s trees, will probably destroy this one too. Yet surely that provides a stronger argument to protect the tree for the duration of its life. The protesters are asking only to be allowed to enjoy the tree for as long as it lives, but the council and landowners have decided that, if its life is limited, they may as well remove it at their convenience. During the week of protest, the owners change their argument from strategic planning to health and safety: they claim that the tree’s roots are raising a sidewalk, thereby presenting a potential hazard.
Financial gain is placed above human wellbeing. Clearly local people feel that the tree is an important focal point for their community. The furore surrounding its fate shows the intense connection that people feel for it and the stories that will be lost when the tree has gone. For a time it will be missed. Ash trees in Britain will be mourned, too, but let us hope that the John Innes Centre, and others like it, are successful in their endeavours to develop a variety of ash that is resistant to Dieback.
In high spring Colt Park Wood still has a wintry aspect. It is a ghost wood in appearance and history, since it is all that remains of a much larger ashwood that originally enveloped the foot of Ingleborough, one of the Yorkshire Three Peaks, in the north of the county. It is believed to date back to prehistoric times, and is comprised mainly of ash, but includes a few other tree types too. Clinging to the lower north side of the peak, at a height of 350 metres above sea level, the trees form a long narrow strip of silver in the sunlight, the only visible woodland in the area. Their bark is bleached the palest grey, as if sucked dry of moisture. The spirits of the people and beasts who have lived in and around the wood linger here. Deforestation and its reduction to its current size has occurred gradually over the last five centuries, due to grazing by livestock, which eat seedlings and strip back the bark, and the felling of trees to clear space for fields.
It is the third week in May 2013 when I drive up the steep track from the Ribblesdale road to the Ingleborough National Nature Reserve with my friend Graham Mort, the poet. I doubt I would have found it if he hadn’t known where to go. I knock on the door of the warden’s barn, an enormous stone structure in a sea of meadow grasses. It is a dry and breezy day, good weather for looking round the wood, Colin Newlands tells me. He is the senior manager at Ingleborough National Nature Reserve so he knows a thing or two about Colt Park. The wood and the adjacent meadows and pastures, including Park Fell, are owned by Natural England. On wet days it is too dangerous to go into the woods because it is too slippery, Colin says. I walk through the meadows, which are dotted with the bright yellow heads of field buttercup and celandine, in sharp contrast to the grey trees. I follow the line of the fence until it stops at a wall where some rough steps, overarched with ashes, lead us down between two arms of the wood.
At the end of the path a flock of sheep scatters downhill. A bracelet of limestone embraces the terrace of wood, a cliff that in places reaches a height of four metres. In the rest of Yorkshire the ash has been in leaf for at least a week but, here, no leaves are in sight: the only green is on the occasional rowan sprouting from the rocks. One grows at a right angle out of the shallow rock face, its trunk as thick as a human thigh.
There is no entrance to the wood, as such, but there are a few places where you can gain a foothold and lever yourself up to the trees. Gaining access to it is not easy for people or animals, because when the Nature Conservancy, a predecessor of Natural England, took it over in 1962, it fenced the wood to preserve it as a sanctuary for rare flora and fauna. Colt Park Wood is shielded