I really am not sure, the Sugar Gum Plantation down by the ranger station was sown between 1939 and 1947 to provide firewood for the Greenvale Hospital, so those trees are 75-80 years old, but I’m guessing many of the very large old red gums would be hundreds of years old.
Woodlands Historic Park 
How old are the big dead trees n the big guns that are struggling to survive
I really am not sure, the Sugar Gum Plantation down by the ranger station was sown between 1939 and 1947 to provide firewood for the Greenvale Hospital, so those trees are 75-80 years old, but I’m guessing many of the very large old red gums would be hundreds of years old.