Implications of the rapid loss of large old hollow-bearing trees in Victorian Mountain Ash forests

Large old trees are keystone structures in many ecosystems around the world. They are termed keystone structures because of their disproportionate ecological value relative to the area they occupy.1 They are characterised by features not found in smaller, younger trees like hollows, large lateral branches, buttresses, and extensive canopies with large numbers of flowers. Large old hollow-bearing trees provide vital habitat for cavity-dependent animals such as Leadbeater’s Possum and other species of arboreal marsupials. They also play a critical role in the structure of Mountain Ash forests of different ages, including influencing the amount of carbon that is stored in these forests, and in key ecological processes like nutrient cycling (e.g. storing large amount of carbon). This Fact Sheet focuses on the many ecological values of large old hollow-bearing trees in Mountain Ash forests in the Central Highlands of Victoria, where populations of these key structures are declining rapidly.