Tougher quarantining of plant material and greater investment in tree health science were among calls made at the Institute of Chartered Foresters' tree health conference in Cardiff last week.
International Union of Forest Research Organizations president Professor Mike Wingfield told the audience of 250 tree and forestry professionals: "The UK could improve its quarantining massively. Europe also has very poor quarantining."
He warned: "New pathogens and epidemics will continue to emerge, probably more than ever before. They are giving rise to new and unexpected challenges - we have 'black swan' events such as novel interactions between beetles and fungi. How can you predict that?"
Wingfield said the growth of plantation forestry globally is a big factor in this. "Huge areas are currently being planted but you are taking trees out of their native range and exposing them to new insects and pathogens. Increasing resilience by mixing varieties or species will never happen. The trend is in the other direction - they want uniformity.
"Collaboration between tree health specialists becomes more important. Face-to-face collaboration is essential. Travel is cheap but dealing with disease is expensive. In South Africa we have a big team and we travel, that's why we are successful. But globally we are doing less, not more. Investment in tree health is inadequate and fails to capture opportunities brought by new tools."
John Innes Centre crop genetics project leader Professor James Brown said: "We need to do something very serious to beef up quarantining. We have to stand up to the EU and say: 'This isn't good enough.'
"We need long-term commitment to rebuilding expertise in forest pathology in the UK, but the funding bodies work on a twoto five-year timescale. We only have seven pathologists at lecturer level working on tree diseases in the UK, and they are far too stretched."
Meanwhile, the rapidly advancing power of genomics "vastly accelerates our ability to answer significant biological questions, while the cost is falling by two-thirds each year".
But he warned of ash dieback: "We won't stop it spreading - it's going to get everywhere and we will lose large populations of ash for 200 years. If it recovers in that timescale, we will be lucky."
Forestry Commission chair Harry Studholme said: "We mustn't forget what we already learned from diseases like Dutch elm disease. But tree disease gets a pitiful amount of money and attention compared with things like hospital beds."
US lesson - Ash borer outbreak highlights need for early planning
America's experience of dealing with emerald ash borer (EAB, Agrilus planipennis) highlights the need for early strategic planning, Davey Institute director of technical services Jim Zwack told the conference.
The beetle, which has ravaged trees in central North America since 2002, "takes 15 years to wipe out a tree population, but even by year six you don't see much damage", he said.
"A recurring comment has been: 'We should have started sooner.' In some places it's up to 50 per cent of the urban tree canopy but there is still no national EAB strategy."
There is no "right way" to deal with it and he warned: "Affected trees lose strength quickly - our guys won't climb in them."
EAB is currently spreading westward through Europe from Russia at an estimated rate of 40km a year.