Tree hollows in Tasmania A guide - CRC for Forestry

How do hollows form?In Australia, some species of animals (e.g.cockatoos) can help enlarge hollows, but nospecies build hollows from scratch. Instead,hollows are produced by environmentalprocesses that take lots of time.The onset of hollow-formation is dependenton damage to the tree, from fire, fromanimals (vertebrates or invertebrates), orfrom branches dropping. Young and healthytrees can quickly heal after damage. As treesage they become slower at healing, allowinghollow-formation to progress. Termitesand beetles can bore into the wood andhollow out extensive areas. Wounds provideentry-points for fungal spores that can leadto active decay, that eventually rot out thetree. Fire can help enlarge hollows createdby other processes (although fire can alsodestroy hollows). Trees less than 100 yearsold are unlikely to contain hollows. Treeswith hollows suitable for use by animals aregenerally more than 150 years old.6Key factors for hollow formation are:• physical damage• fire• fungi• invertebrates (e.g. termites and beetles)• time.A hollow partially formed byfire (top);fruiting fungal bodies near abasal hollow (bottom).