Researchers from the Australian National University released a study on Tuesday, based on 35 years of research of the forest.
Lead researcher Professor David Lindenmayer said in a statement: “Wildfires and over-logging have tipped the Mountain Ash forest very close to collapse – populations of animals living there have halved, and in some cases have declined by more than 65% during the past 20 years."
The study claims to provide the first empirical evidence that the forest is facing imminent collapse. It found that a primary cause was the loss of half the population of large old cavity trees, which animals depend on, during the last 20 years.
“Since 2004, there have been significant declines in almost all species of tree-cavity reliant bird species including the Laughing Kookaburra and Crimson Rosella.”
If a collapse were to take place, then the Mountain Ash trees, which grow to a height of 100 metres, would be replaced by Acacia shrubs, changing the ecosystem.
“If we don’t act quickly to turn this dire situation around, we will have a crisis on our hands,” Prof Lindenmayer said.
“Not only does the Mountain Ash forest in Victoria generate nearly all of the water for the 4.5 million people living in Melbourne, it also stores large amounts of biomass carbon and supports timber, pulpwood and tourism industries.”
Prof Lindenmayer said replacing the lost cavity trees would take 50 years, and the trees that remained needed to be protected.
“We urgently need major changes to forest policy to rectify this situation, especially greater protection for large old trees,” he added.