Photo: South Wales Fire and Rescue Service/PA Media BETTER land management could be the key to preventing wild fires that blight much of Wales every spring, but firefighters are mystified as to why so many are set deliberately, and without any apparent motive. Last week a deliberately started fire burned on a mountainside at Machen near Caerphilly for at least four days and had to be tackled by a helicopter water-bombing the site as the blaze spread across 50 hectares (around 123 acres). It was just one of around 100 wild fires on grassland or mountainsides across Wales that were burning, or broke out, during a 24-hour period at the beginning of the week following a prolonged dry spell, with the majority in the South Wales valleys.