Natives and continentals in clash of the ash

EYE ON NATURE:THE FIRST REAL gales of autumn set the acre a-whirl with leaves – and began to paint in the world around us pixel by pixel, as it were.

Mountain and hillside fields have been re-emerging gradually between the branches whipping and creaking about the house. In summer, the trees close in to muffle the passing traffic, leaving us a vista of sea and shore only moderately circumscribed by the ash outside the window, but now most of its long-fingered leaves, too, have shredded and flown, showing us more of the morning reach of sun across the dunes.

In one way that’s a pity, since an ash tree in autumn can be lit up by a rising sun in a breathtaking aureole of glowing lemon and greengage (there was one at a bend in the Maam valley the other morning, all ablaze above its ivied trunk, that I have done my best to recall in the drawing).

But our ash is just as striking when stripped to the skin, its smooth, supple arms springing from the trunk in powerful, knobbly sockets, like a Belfast boxer.

The branches form a balanced candelabra unusual on a coastal hillside where most trees are shaped so severely by ocean winds: perhaps the late budburst of the ash saves it from the desiccation of its windward shoots. But it is still, of course, a tree to horrify a forester. Its crown begins to spread not much above my head instead of far aloft on a single, straight stem at least six metres high. But you get straight timber from crowding ashes at the recommended 3,300 plants per hectare, so that they must reach for the sky.

At least our tree’s hard winter buds are positively velvety black, which marks it as a proper Irish ash (filched as a seedling from a path through old forest near Cong) and not one of the alien breed from Continental Europe that are threatening the genes of the native common ash Fraxinus excelsior.

Back in 1992, when substantial grants began for planting hardwoods in farm forestry, the shortage of native stock meant that a lot of ash plants and seed were imported from European countries where the common ash has hybridised with a sibling species, Fraxinus angustifolia. This narrow-leaved ash is a big, vigorous species from southern Europe and western Asia, and with rugged mature bark and dark-brown winter buds, is thought decorative enough for city parks.

The European stock, planted in Ireland up to 2000, looked fine to begin with, but within about five years, trees in some plantations began to show “very bad stem form”, as foresters say – that is, getting distinctly wiggly the taller they grow). The potential pollution of native ash germplasm through hybridisation is a serious concern, especially as climate change, with its impact on flowering dates, could well increase the risk.

Botanists from Teagasc, Trinity and the University of Paris have been touring Irish ash plantations to assess the spread of the crooked trees and the chances of their cross-pollination with native ash. In nine suspect plantations, most of the trees sampled were hybrids, and most in two closely-studied Leinster plantations showed the typical mid-winter flowering of Fraxinus angustifolia that overlapped spring flowering of the native species.

So the hunt is now on for the more obvious aliens before they can flower again, though I don’t know what that says about the various decorative varieties of angustifolia that have been blooming for many decades in arboreta such as those at Birr Castle, Co Offaly, JF Kennedy Park in Co Wexford, and other big Irish gardens.

One can see how the miscegenation could matter. Ash is a really important hardwood tree for the future of Irish forestry. Never mind the hurleys – the whole market for them can be supplied by around 50 to 60 hectares a year – but furniture, boats and tool handles create a constant demand for ash of high quality produced by industrial methods matched to nice straight trunks.

There are, of course, other, more beguiling, things you can do with ashes as they grow. In his lovely book Wildwood: A Journey Through Trees, the late Roger Deakin gave his final chapter to the ash, and in particular to a woven bower he created as a kind of folly at the top of his long meadow in Suffolk. Planted some 20 years ago, it consisted of “a double row of lively ash trees bent over into Gothic arches like a small church”, their branches grafted together and pollarded over the years. “In the summer heat it is a cool, green room roofed with wild hops and the flickering shadows of ash leaves. I sometimes sling a hammock inside.”

Just one more idea I’ve learned too late.