In this review of pollen data from the South Swedish uplands, evidence is presented of colonisation and strong agricultural expansion during the 11th to 13th centuries, followed by farm abandonment and land use change during the 14th to 15th centuries. The latter is associated with the Black Death and the late medieval crisis. Pollen data show that abandonment in the uplands resulted in the regrowth of woodland, but also in land use change from cereal growing to grazing. Similar cycles of agricultural expansion and decline are identified also from earlier periods during the Iron Age, which highlights the sensitive character of upland agriculture and settlement.