Mixed Forest is a type of Cool Temperate Rainforest, where rainforest trees grow as an understorey amongst old-growth giants. It is very rare, only occurring in places that have not had fire for a very long time.
The Mixed Forest definition used by the Department is as follows:
Definition
"Mixed Forest is Wet Forest which has an overmature or senescent eucalypts (usually Shining gum, Mountain Ash, Cut-tail or Alpine Ash) with crown perimeter cover of 10% or more AND a closed understorey (projected foliage cover of greater than 70%) of which more than 50% is contributed by one o rmore of the following species: Southern Sassfras, Black Olive-berry, Banyalla, Gippsland Waratah, Privet Mock-olive, Mountain Plum Pine, Errinundra Pepper and Blackwood, (provided this species comprises less than 50% of the rainforest character species contribution to the cover in tis stratum).
Prescription
Stands of Mixed Forest of 0.4ha and linear strips of at least 20m wide and at least 100m long are to be protected from harvesting and disturbance.
Mixed Forest stands are to be protectde by a 20m buffer."
Mixed Forest stands at Dingo Creek were declared "not rainforest" by the DNRE, as the size of the stands were less than 0.4 ha. This is despite the East Gippsland Management Plan claiming that small stands "too require protection". It is also illogical, as most Mixed Forest stands are less than 0.4 ha; they represent a young, emerging rainforest, which are known to kill eucalypts by allowing saturation of the soil. Counting rings on the stumps of the Sassafrs trees cut down at Dingo Creek showed they were 120 years old. Stands that develop over 0.4ha become pure rainforest.

Seen above, the pointed trees are Sassafras, a rainforest tree, growing as an understorey. You can see the stand is 100% Sassafras, fulfilling the species mix requirement, and that the edges of each tree touch, fulfilling the canopy density requirement.
You can see clear sky above the stand of Sassafras, and that they continue under the canopy to the right. This is typical; the rainforest grows in a sink; a local depression that has wetter soil, and continues under the eucalypt canopy as Mixed Forest.
This particular stand was abut 1km from the nearest flowing stream and recognised stand of rainforest.
The debri in the foreground is the logging operation in progress, which went on to demolish this stand of Mixed Forest.