 During the Great Depression, a severe and prolonged fall in the prices of wool and cereals due to rising volumes of imports from the British Empire was accompanied by the Wet Years - a six-year period of cold, wet weather with little sun.In the Second World War, the South Downs were commandeered for military training, only fringe farms being left to produce milk for the towns.Sheep farming declined further after the war, although it is now being encouraged again through the designation of the downland as an environmentally sensitive area, and the restoration of arable land to sheepwalk.