This week we look at agroforestry - that's farming with trees in the mix. We visit farms using trees for different reasons - including providing shade for livestock, adding nutrients to soil, and providing habitats for useful insect predators.

And the UK's second largest greenhouse - which could replace 7 per cent of the tomatoes the UK imports - has been given the go ahead. Rivenhall Greenhouse near Braintree in Essex will cover 40 hectares and use power from a domestic waste incinerator - burning all the black bag waste from the county.

Presented by Charlotte Smith and produced by Sally Challoner.