Acute oak decline

Acute oak decline (AOD) is a disease that infects oak trees originally described in the UK. It mainly affects mature oak trees of over 50 years old of both Britain's native oak species: the pedunculate oak (Quercus robur) and the sessile oak (Quercus petraea). The disease is characterised by the trees bleeding or oozing a dark fluid from small lesions or splits in their bark. Unlike chronic oak decline, acute oak decline can lead to the death of trees within 4 to 5 years of symptoms appearing. The number of trees affected is thought to number in the low thousands, with a higher number of infected trees being found in the Midlands.