100,000 young ash trees were destroyed in Northern Ireland in an attempt to combat the disease.
Trees could be protected from the devastating ash dieback disease with the help of a natural soil treatment, researchers have claimed.
A newly developed "enriched biochar", which combines a purified form of charcoal with fungi, seaweed and worm casts could help ash trees resist the Chalara disease, according to research by tree and shrub care company Bartlett Tree Experts.
A study by the company's research labs on 2,000 established ash trees over three years in Essex found that while a third of the established trees monitored have become infected with Chalara, none of the 20 trees which had enriched biochar applied to their roots were hit.
Chalara ash dieback, which could kill millions of ash trees, was first identified in the UK in 2012 and experts fear it could have the same devastating impact on the country's woodlands and landscape as Dutch elm disease in the 1970s.
It has been found on around 100 sites in Northern Ireland.
All those sites were planted with imported saplings, some of which had the infection.
Dr Glynn Percival, head plant physiologist at the Bartlett Tree Research Laboratory, said: "While we cannot claim this to be a cure for ash dieback, we are clear that it has a beneficial impact.
"We will need to run further trials to be clear on its qualities to prevent the disease taking hold, but this is an important discovery and we believe using enriched biochar could help improve the survival prospects for the UK's ash trees."
He added that the biochar, which has been developed by company Carbon Gold in collaboration with Bartlett, could also have positive benefits for protecting trees from other significant diseases.
The study, funded by Bartlett and the University of Reading, originally aimed to evaluate enriched biochar as a natural boost to tree health.
The Woodland Trust, which is involved in studies to find natural resistance to Chalara in ash trees as part of its work against the disease, said the results from the biochar trial "seemed promising".
Nick Atkinson, conservation adviser for the Trust, said: "European ash is an important native species in the UK and we could see the loss of many millions of individual trees over the coming years, which will have a huge impact on the wildlife they support.
"Whilst there is hope that some trees will prove to be naturally tolerant to the ash dieback fungus, anything that can help stack the odds is welcome and these findings do seem promising.
"We would welcome further research to build on Dr Percival's work, in particular to look at the effect of biochar soil amendments on mature trees, which play host to many species and cannot simply be replaced overnight."