Last century the Forestry Commission sparked anger with a mass planting of conifer trees designed to provide a national reserve of timber because the shortages of the first world war had highlighted a national need.  Now a leading expert is calling for similar action again, arguing that if the UK is serious about offsetting its carbon dioxide emissions it must plant tens of millions of trees from imported species on open land. John Healey, professor of forest sciences at Bangor University, says that relying on indigenous species such as oak and beech will make it impossible for the government to hit its climate goals. Britain will have no choice, he says, but to engage with the commercial sector in large-scale planting of imported conifers, despite fears of the impact on habitats and wildlife.