Monitoring for Myrtle Wilt in Nothofagus cunninghamii populations, Tasmania


19 April 2023




Nothofagus cunninghamii is an Australian endemic species and a dominant tree in the cool temperate rainforests of Victoria and Tasmania. Like many other species of Nothofagus, it is threatened by logging, fire and climate change, but in addition to these threats, N. cunninghamii is the only known naturally-infected host of the fungus Chalara australis which causes Myrtle Wilt disease. Risk to N. cunninghamii is greatest on sites of forest disturbance and increased global temperatures and human activity are causing increased stress and mortality of this species, which has recently been globally assessed as Vulnerable.

An important new project has been launched by Inala Jurassic Garden to monitor for Myrtle Wilt on Bruny Island, Tasmania, Australia. The project, run in partnership with Wakehurst (Royal Botanic Gardens, Kew) and funded by BGCI ArbNet Partnership Programme, will monitor an in situ population of Nothofagus cunninghamii (Myrtle Beech) and collect genetic and reproductive material for storage and research.

It will involve both ground surveys and aerial surveys, the latter carried out by a drone, over a one-year period to assess whether populations are affected, and to what extent. This study is an important pilot study for further broader, long-term monitoring over the species’ range.

This fungal pathogen was first recorded as a disease that infects and kills mature Myrtle Beech in cool temperate rainforests in Victoria by Howard in 1973 and was formally described by Kile & Walker in 1987. Research by Packham (1994) outlined a suitable monitoring technique for the health status and damage to Myrtle Beech in 28 sites within Tasmania, but there has been very little published since this time. Long-term research in the southern forests of Tasmania indicates a concerning increase in death of Myrtle Beech over the past decade (T. Wardlaw, pers. comm.)

This pilot project has the support of a large range of stakeholders, including the Tasmanian Seed Conservation Centre, Royal Tasmanian Botanical Gardens, the Australian Native Plant Society (Hobart Tasmania branch) and researchers at the University of Tasmania. Volunteers from the local community will conduct the surveys under the leadership of Dr. Tonia Cochran (Curator and Collection Manager Inala Jurassic ) following survey techniques first developed by Packham (1994) to monitor the health and damage to this species.

Olivia Steed-Mundin (Wakehurst, Coordinator for the GCC Nothofagus): ‘given the importance of Nothofagus cunninghamii to the cool-temperate rainforest ecosystems in Tasmania and Victoria, reports of Myrtle Wilt symptomatic trees are concerning. It will be very valuable to gather data that will add to our understanding of the current threat from this disease. We are extremely pleased to partner with Inala Jurassic Garden, whose exceptionally proactive approach, expertise and links with local stakeholders are central to the success of the monitoring programme. The project also provides a great opportunity to develop a methodology that may be replicated in other locations if required’. 

Dr. Tonia Cochran (Curator and Collection Manager Inala Jurassic Garden): ‘we are delighted and proud to partner with Wakehurst, RBG Kew and appreciative of the support of BGCI/ArbNet who have recognised the importance of monitoring the health of in-situ populations of these ancient Gondwanan relicts. This project also provides a great opportunity to raise awareness of this issue and involve stakeholders at the local community level’.

Dan Crowley (GCC Manager): ‘given the troubling disease impacting Nothofagus cunninghamii in the wild, it is important to gain more of an understanding of the state of populations to inform conservation efforts for the species. In this and other projects, Inala’s contributions to plant conservation are an inspiration for smaller gardens, and their involvement in the GCC for Nothofagus is greatly appreciated’.

Jo Wenham (Curation Manager Wakehurst, and Coordinator of the GCC Nothofagus): ‘this important data collection and monitoring work provides a real practical kick start to the work on Myrtle Wilt and its effects on Nothofagus cunninghamii. Vitally, it emphasises the importance of in country partners, species stewards and affiliates to Global Conservation Consortia thus ensuring the success of these collaborations. We are excited to be working so closely with such a passionate partner in Inala Jurassic Garden in Tasmania’.















Nothofagus cunninghamii, Myrtle Wilt infection likely causing death of tree: Olivia Steed-Mundin