Ash dieback signs emerge in UK woods
12 June 2013 Last updated at 12:36 BST
The Forestry Commission says a whole generation of ash trees will die with the unstoppable spread of the ash dieback disease.
It is a year since it was first discovered in the wider environment and ancient woodland. Now the trees are in leaf, the impact of the disease is starting to become evident.
Here, the BBC's Jeremy Cooke speaks to Austin Brady from the Woodland Trust at Pound Farm in Suffolk, which was one of the first places in the UK where the disease was found.