Ash dieback was discovered in the UK in late 2012 and since then has been killing many of the UK's ash trees. But it's not the only threat - many pests and diseases are attacking different species which make up our forests and ancient woodlands. Julian Rush asks if our trees are simply vulnerable victims, susceptible to diseases, or if they have the strength to fight back.

He visits Wentwood in South Wales where phytophthora ramorum (PR) has infected larch trees causing the clear felling of over 70 acres, with more anticipated. He asks if this is the only solution and how the loss of the trees will also affect the animals and insects.

As ash dieback also spreads across the UK, Julian visits the scientists working to trace a natural resistance in trees and breed a new stronger generation of trees. The urgency of the situation has forced them to share their findings sooner, open sourcing information and enlisting the help of the public which has already led to new findings and chance developments which might not otherwise have been discovered. Julian asks if enough is being done soon enough and if the scientists or the diseases are winning the race.

With a swathe of other diseases also threatening he asks if we have to learn to live with disease and accept that change in our forests is inevitable. We are also talking to the chair of the committee of the Environment Food and Rural Affairs Committee who published their new report on Tree Health and Plant Biosecurity this week.