A plan to reverse the destruction of elm trees in Ireland by Dutch Elm disease, which has left the country with only a tiny number of healthy mature trees, is being put in place by Teagasc.
Once as common as ash or oak in Ireland, the elm trees were killed off by a fungus which is carried by flying beetles which eat elm leaves.
A report in the current edition of Teagasc's T Research magazine, says the disease has been found in all counties and most populations of mature elm trees have been killed.
"Elms were once to be found in every Irish townland and were as known to people as ash or oak. Finding a mature elm today in Ireland is not easy," according to Dr Gerry Douglas.
"A healthy elm is something rare, to be valued as part of our genetic resources and most trees were wiped out by a world pandemic," said Dr Douglas, principal research officer at Teagasc's Kinsealy Research Centre.
"A few mature individual trees remain in a healthy state in places such as Leitrim, Longford, Meath and Louth and small groups of elms can be found in coast counties such as Cork, Mayo, Donegal and Galway, as well as on Inis Mór," the report says.
Scientists believe that individual trees that remain may carry a higher level of resistance to the disease and this may also be true for elms in coastal counties.
The Teagasc conservation plan involves locating, conserving and promoting the planting of elms derived from remnant Irish trees.
Scientists are seeking out species for which sexual reproduction is a significant means of producing offspring in the main species in Ireland, Ulmus glabra (Wych elm) and Ulmus minor of which there are many forms.
Seed production by elms and natural regeneration of elm through seed was generally erratic. However, in 2006, a group of trees at Ardee were identified with abundant seed that germinated to produce 15,000 saplings when grown at the Coillte nursery in Co Wicklow.
The conservation work is now concentrating on propagating mature tress and on making a collection of as many mature elms as possible.
"To maximise biodiversity within the elm collection it is important that we have as many different genotypes as possible," the report by Dr Douglas says. "So far we have located over 80 mature elm trees in Ireland, all apparently healthy. So far, 3,000 cuttings have been taken from the elms and the rooting rate was 10 to 77 per cent depending on the elm tree. These plants are now being grown to sapling stage and will be returned to the owners. For longer term conservation of elms, it is appropriate and useful to grow the collected elms in the field and to maintain them in the form of a hedge.
"Elm beetles are most attracted to trees over 1.5 metre in height, so trees in the form of hedges are safe from infection. We plan to establish such a conservation collection at an Irish arboretum, such as the National JFK arboretum at New Ross, Co Wexford," the report says.