This fact sheet written by John Woinarski and Brydie Hill presents the key findings from the Land & Water Australia managed project: Defining successional patterns and biodiversity values of north Australian eucalypt forests. Overall, this study provides major new insights into the dynamics of these important tropical eucalypt forests, particularly allowing comparison with the dynamics of temperate eucalypt forests. The study has important management implications. It is now possible to provide some explicit quantitative criteria for the delineation of "old-growth" in these forests (relating particularly to the incidence of larger trees, and the consequential abundance of hollows and hollow-associated fauna). For regrowth vegetation, it is now possible to justify regulatory controls; although we recommend that if there is a need for choice, it is better to (re-)clear regrowth than to clear intact forest, better to clear younger than older regrowth, and better to clear isolated regrowth than regrowth that may form connections between otherwise isolated intact forest patches.