This chapter outlines the Commission’s work on national estate forests and the impact of forestry operations on their significance. It addresses a number of related issues: the concept of national estate forests, including the fauna in those forests; the methodology used by the Australian Heritage Commission when assessing the significance of those forests; the implications of the resource security legislation/debate on the long-term survival of the forests; and work of the Commission to investigate and assess the impact of forestry operations on the national estate values of forests. The Commission considers that there are adverse impacts on fauna values arising from forestry operations, with some species particularly vulnerable to forestry operations. However, the paucity of scientific knowledge, particularly about conserving invertebrate fauna, makes it difficult to assess possible impacts accurately. The Commission’s findings indicate there is a need to obtain a more detailed understanding of the biology, habitat requirements and distribution of all forest fauna species to ensure their long-term survival, particularly rare species or species which are considered to be dependent on old-growth forests. Even though the Register of the National Estate contains many places with forest values, including significant fauna values, it is not complete. It is anticipated that systematic work in co-operation with state government organizations will result in an improved understanding of Australia’s national estate forests. Zoologists can also contribute by identifying fauna values of national estate significance in forests and furthering research to enhance knowledge of forest fauna.