New Roundup Study, Ash Dieback Research, Brecon Beacons National Park

A new study shows liver disease in rats which have ingested very low levels of glyphosate. But is the science robust enough to re-assess one of the most widely-used weedkillers in the world?
Ash trees have been threatened by the dieback fungus, but sequencing the ash tree genome has now shown the UK ash trees are distinctly different from their European and Scandanavian cousins, and are less susceptible to the disease than previously thought.
All this week we are hearing stories from Britain's National Parks. Today, we're exploring the Brecon Beacons in South Wales.

Presented by Anna Hill and produced by Beatrice Fenton.