Abstract
Sustainable management of native forest gene pools requires an understanding of the levels and spatial patterns of genetic diversity in tree species. This diversity impacts on numerous management issues including seed transfer guidelines and in situ genetic resource conservation. Our long-term studies of Eucalyptus globulus (Tasmanian Blue Gum) have provided unprecedented insights into the complexity of the genetic variation that can exist in natural populations. We demonstrate that E. globulus comprises a fine-scale mosaic of family groups superimposed on a complex spatial pattern of local and broad-scale adaptive and non-adaptive genetic variation. The high level of genetic diversity observed within forest tree species such as E. globulus, coupled with their flexible breeding systems, provides the fundamental elements for adaptation to futureenvironmental challenges.