Ash dieback was first noticed in the canton of Basel in 2008 but has since spread to all cantons, a meeting of federal environment and cantonal forest inspectors was told on Thursday.
The disease is caused by a fungus called Chalar fraxinea which causes leaf loss, damages bark and kills branch tips.
Officials at the meeting in Olten in the canton of Solothurn said there was currently no effective way of combatting the fungus, although there are options for replacing ash trees with disease-resistant varieties.
“We must not abandon the ash,” Ueli Meier, chairman of the conference of cantonal forest inspectors said, according to a report from the ATS news agency.
“We do not have a replacement in Switzerland.”
Meier said the spread of ash dieback among stands of young trees was “particularly dramatic” and showed no sign of improving.
Ash is used to make tools, and sports equipment including archery bows, and also makes good firewood.
Officials said the propagation of cloned trees that are resistant to the fungus is one solution.
Planting disease-resistant elm trees is another option, as well as targeted surveillance, ATS reported.
Experts say the planting of more ash trees should be avoided and the status of diseased stands should be regularly controlled and reevaluated.
Ash dieback disease is being increasingly found in countries across continental Europe after cropping up in Poland in 1992 and was first discovered in the UK in 2012.
According to the UK’s Forestry Commission, evidence from continental Europe shows that older mature ash trees “can survive infection and continue to provide their landscape and wildlife benefits for some time”.
However, it said the fungus, spread by wind, can kill young ash trees quite quickly.