Saving the world’s tallest flowering plant with seedbanks

Victoria's ash trees are the giants of Australia’s forest landscape. 

Mountain ash (Eucalyptus regnans) is the tallest flowering plant on the planet, reaching heights of 50 metres within 35 years of germination, and over 100 metres if lucky enough to survive a few hundred years.

The luckiest ones live up to 500 years! Even after death their skeletal remains can persist in the ground for a further 75 years. Mountain ash forests evolved over a period of over 20 million years.

Alpine ash (Eucalyptus delegatensis) is cousin to the mountain ash and, given the right conditions, can reach heights of 90 metres. Victoria’s ash forests include valleys of ancient Gondwanan rainforest, snow gum plateaus, and the remains of extinct volcanoes. They're home to threatened marsupials like the southern greater glider.

The significance of Victoria’s ash forests cannot be overstated. The ash forests sustained First Nations peoples and even today, mountain ash forests provide water to over five million Melbourne residents and provide a place of culture and beauty for people to visit and reconnect with nature.

Victoria’s forests are precious natural assets, with many social, economic and environmental benefits. These include conservation of threatened native species, natural carbon sequestration, and unique cultural and social experiences. 

When the 2019–20 Black Summer bushfires tore through eastern Victoria, the alpine ash forests were decimated. The Bushfire Risk Assessment and Modelling of the Alpine Ash Forests of the Australian Alps National Parks and Reserves Report published by the University of Melbourne estimate 140,000 ha for alpine ash was impacted in the 2019-20 Black Summer bushfires. 

It takes about 20 years for ash trees to mature and produce seeds for regeneration, and with increasing frequency of fires it is becoming challenging for these trees to reach maturity in time.

This is where seedbanks can play an important role in conserving Victoria’s threatened plants. The donor-funded Victorian Conservation Seedbank (VCS) is Victoria’s primary facility for conservation of the state’s most threatened plants. It stores the seeds and spores of native Victorian plants, particularly endemic and at-risk species. These form the basis for their research into effective, long-term germplasm storage, germination characteristics, and the propagation of recalcitrant native species. 

The VCS, supported by associated laboratories and plant propagation nurseries at Royal Botanic Gardens Victoria, forms part of the Gardens’ Bushfire Plant Recovery and Care Unit, which aims to support the restoration of fire-damaged landscapes and ecosystems. The VCS currently holds over 2,200 collections covering 1,500 taxa. 

“Since the Black Summer of 2019–20, the Victorian Government has worked alongside private agencies to help collect, bank and sow seeds, to regenerate some of the lost mountain ash forests before it’s too late.”

Alastair Robinson, Manager Biodiversity Services at Royal Botanic Gardens Victoria

Find out more about seed banking: 

• Science insights give seeds and seedlings a helping hand