Document ID: chunk:federal_register_of_legislation:F2024L00270:body:0:p22
Version: federal_register_of_legislation:F2024L00270
Segment Type: other
Provision Reference: 
Character Range: 60224–63145

ash forest, Leadbeater's possum occurs at highest densities in multi-aged forest containing several age classes of eucalypts, including live and dead hollow-bearing trees, together with a dense midstorey of wattles (notably A. dealbata, A. obliquinervia, A. melanoxylon or A. frigescens) (Lindenmayer et al. 1990a; Lindenmayer et al. 1991b; Smith and Lindenmayer 1992; Lindenmayer et al. 1994b). They also regularly occur at the eucalypt forest – rainforest ecotone and in montane riparian thickets along gullies embedded within montane ash forests (D. Harley unpublished data; DEECA unpublished data).
In these tall forests, the occurrence and density of Leadbeater's possum is strongly associated with hollow availability. There is a significant correlation between the incidence and abundance of Leadbeater's possum and the density of hollow-bearing trees on a site (Lindenmayer et al. 1991b; Lindenmayer et al. 1994b), although this relationship is less pronounced in reporting of results from recent years (Lindenmayer et al. 2011b; Lindenmayer et al. 2014b). The absence or low abundance of resident Leadbeater's possums on sites with few potential nest trees is thought to be due to competition for hollows from other species, a requirement by individual colonies of Leadbeater's possum to use more than one nest tree and because of their specific hollow requirements (Smith and Lindenmayer 1988; Lindenmayer and Meggs 1996; Lindenmayer et al. 2018). However, the species may show some flexibility in its selection of nesting sites where there are low numbers of hollow-bearing trees by using a wider variety of types of hollow-bearing trees (Lindenmayer et al. 2011b).
In the montane ash forests, the abundance of suitable nest trees is tightly correlated with disturbance history (Lindenmayer et al. 1990b; Lindenmayer et al. 1990c; Lindenmayer et al. 1991a; Smith and Lindenmayer 1992; Lindenmayer et al. 2016). For the dominant mountain ash trees, hollow formation does not start until the trees are about 120 years old, and the hollows with large internal cavities that are preferred by Leadbeater's possum typically do not form until the trees reach 190–220 years old (Smith and Lindenmayer 1988; Lindenmayer et al. 1991c).
Peak densities of Leadbeater's possum occur in regrowth forests (15–50 years after bushfire), in which stags may supply abundant tree hollows (depending upon the age of the forest at the time of disturbance), and there is a high biomass of wattles (20–50% of stand basal area) and eucalypt regrowth (Smith and Lindenmayer 1988; Lindenmayer et al. 1990a; Lindenmayer et al. 1991b; Lindenmayer et al. 2000). Dense regrowth after timber harvesting can also provide suitable foraging habitat if there are sufficient suitable nesting sites within the regrowth or in adjacent areas (Smith et al. 1985; Nelson et al. 2015; Keith et al. 2016; Nelson et al. 2017). A recent study reported that