What is the Chalara ash dieback tree fungus disease?

A deadly fungus is spreading "more quickly and lethally" through the UK's ash trees than experts had anticipated, BBC Wales has learnt.

Millions of diseased trees near buildings, roads and railways will have to be cut down.

Natural Resources Wales (NRW) warned of a "very significant impact" on the landscape.

So how does ash dieback behave?

  • Wales