Experts are warning that forests in Wales will face even more problems from pests and diseases because of climate change.
Trees here have been hit by recent outbreaks affecting ash and larch and more problems are expected in the future.
A project team called IMPACT has been set up to come up with ways of tackling outbreaks without having to use pesticides. It has European funding and involvement from Swansea University.
It follows one of the worst years on record for destruction in Welsh forests, with thousands of trees having to be felled.