The West Vic volunteers planting 30,000 trees a year to bring koalas back to their rivers

Each year, landholders across western Victoria plant tens of thousands of trees along the Moorabool and Barwon river corridors, rebuilding koala habitat devastated from decades of clearing.

The work is being led by Bacchus Marsh’s Koala Clancy Foundation, focusing on revegetation along fertile river flats to help koala populations survive hotter, drier conditions.

How it started: Foundation president Janine Duffy told the Brolga the program began in 2015 after steep declines were observed in local koala numbers, largely linked to drought, heatwaves and long-term habitat loss.

• The organisation now runs planting events, with about 30,000 trees added each year and a long-term target of 300,000 plantings by 2030.

🗣️ “We officially started that target in 2020 so it's only the sixth year, and we're well above half,” Duffy said, noting the group recently passed 190,000 plantings.

How it’s going: Duffy said the foundation is seeing hard evidence of its work already.

🗣️ “At Lethbridge, we planted a good number of trees, in that year we did audio recordings when we first planted the trees, one year later we got a three times increase in the number of koalas calling,” she said.

🗣️ “We had one project we planted in 2021, we went out there last year to just collect tree guards, and we found a koala on that day, and the landowner turned around to me, and said, ‘we did it’. We both bawled.”

Heat hits hard: Climate extremes are already having a direct impact on koala survival, even when conditions don’t appear particularly devastating on paper.

• Research conducted by the University of Sydney earlier this year found adult koalas were at a higher risk of death once seven-day maximum temperatures were higher than 27 degrees.

• Koalas were 1.5 to 3.5 times more likely to be hospitalised or die when exposed to temperatures above 30 degrees compared to 25 degrees.

🗣️ “These animals are already on a knife’s edge of survival. They're skinny, their immune system's low, they're not getting enough to drink or eat,” Duffy explained.

What’s affecting populations? A combination of historic land clearing and more recent climate change impacts has left koala populations increasingly reliant on narrow riverine corridors.

🗣️ “They need homes, not highways,” she said, describing how koalas are often forced to move along thin strips of remaining riverside vegetation without stable habitat to settle and breed.

Where do they plant? The planting work takes place on private land, which Duffy said is essential due to soil fertility and their closeness to waterways.

El Niño worries: Duffy said the Bureau of Meteorology’s recent El Niño declaration reinforced the urgency of careful, targeted planting rather than slowing restoration efforts.

🗣️ “If landowners get behind this, it could mean the difference. We've got this really short window, five, maybe 10 more years we can do it and actually really make a difference for koalas.”

Rethinking the work: Laura Hollingsworth joined the foundation’s project earlier this year and hosted her first tree planting event at her 11-acre property at Maude, near Bannockburn, on the weekend.

She explained she had concerns that drier conditions created by El Niño and climate change could slow the growth of newly planted trees.

🗣️ “I've seen that happen in the eight years that I've been living on the property, but that's because we've had good rains, that made all the difference to the tree planting that I did, they're 20 feet high now.”

🗣️ “Whereas if we have this El Niño, we have to manage what we decide to plant … but our climate and our weather events shouldn't shape our actions necessarily, they shouldn't stop us from trying to do that great work in our environment.”

How many koalas are in West Vic? Data on koala numbers in Victoria has not been updated since 2023. 

• Results of the Great Victorian Koala Survey  were meant to be published in 2025 as part of the state government’s new Koala Management Strategy. 

• Victoria’s most comprehensive koala monitoring project is meant to provide a clearer picture of koala populations after the region’s recent drought and bushfires.

• The results are yet to be finalised.

Header image credit: Koala Clancy Foundation, Vic / Louisa Jones