Work carried out by Watkins and Lavers (1998) has produced a database of the cohort of ancient oak trees surviving within the remnants of Sherwood Forest, Nottinghamshire. The database shows that around 35% of the cohort of ancient oaks is entirely dead and large sections of many of the live oaks are dead (Clifton 2000a; Clifton 2000b). This dead wood resource is of enormous nature conservation and historical importance (Lott 1999; Watkins 1998), yet little is known about when the trees died, how long largely dead trees may remain alive and how long the dead wood is likely to survive before rotting away. This project uses tree ring data from 92 trees to estimate the date of death or likely longevity of surviving ancient trees. This information is important in determining the future management of the remaining fragments of Sherwood Forest in Birklands and Bilhaugh cSAC. Factors influencing tree death are also explored. This information provides a basis for the development of management strategies to ensure the long-term supply of old oak trees.