Everything about this park seems ancient. From the towering Mountain Ash trees to the moss-covered rainforests. This is a heartland for some of our nocturnal possums and gliders. Bring a torch and see if you can spot a Greater Glider or Yellow-bellied Glider in the tall trees but be sure to watch the ground for grumpy wombats.

The forests of the Yarra Ranges are thought to be among the last strongholds of the critically endangered Leadbeater's Possum. This shy animal needs a particular mix of trees of varying ages to thrive and has suffered from habitat loss due to bushfires and logging. You are unlikely to see a Leadbeater's Possum, but it is nice to know that one might be resting in the hollow of a tree as you walk past.

In all, around 40 native mammals are known to occur in the park. The large areas of undisturbed old and mixed-age forests are particularly important for the conservation of hollow-dwelling species including bats, owls, parrots and the Leadbeater's Possum.

The park provides habitat for 120 species of native birds. Hollow-using species found here are the Sooty Owl, Powerful Owl and Barking Owl. Other important species include the Pink Robin, Yellow-tailed Black Cockatoo, Australian King-Parrot and Grey Goshawk. Crimson Rosellas are common.

The park features tall Mountain Ash forests, with an understorey of tree ferns, and gullies of cool temperate rainforest. Large pristine areas of these and other vegetation types are of national and state botanical significance. Damp river valleys are home to stands of Myrtle Beech festooned with mosses, ferns and lichens.

The highest elevations, such as Lake Mountain and Mount Donna Buang, are characterised by sub-alpine vegetation, and receive regular snowfalls over the winter months.

Fourteen plant species occurring in the park have been identified as being rare or threatened, including the Slender Tree-fern and Tree Geebung.