Large old trees are keystone structures in numerous ecosystems globally. They play a wide range of critical ecological roles and therefore quantifying the factors influencing their distribution and abundance therefore has significant management implications. Yet, there are few ecosystems worldwide for which quantitative statistical models of the factors affecting large old tree distribution and abundance have been produced. We constructed a suite of such models using cross-sectional data on the occurrence of large old hollow-bearing trees gathered in 2015 on 166 sites, each of 1 ha in size within the montane ash forests of the Central Highlands of Victoria, south-eastern Australia. Our analyses included two broad groups of models, those for: (1) the overall abundance of large old hollow-bearing trees at a site, and (2) the abundance of large old hollow-bearing trees in four different morphological states of decay. These were large old living trees, large old hollow-bearing trees deemed potentially suitable for marsupial gliders, large old hollow-bearing trees deemed potentially suitable for non-gliding marsupial possums, and large old collapsed hollow-bearing trees.