Date released
14 December 2022

Australia has exported its acacia and eucalypt tree germplasm around the world, with plantations  providing valuable incomes for smallholder farmers across South-East Asia and Africa. Acacias, and now eucalypts, also provide the foundation for large-scale commercial plantations in countries such as Indonesia.

ACIAR-funded research is helping partner countries plan for and respond to biosecurity threats, which in turn helps Australia improve its own biosecurity preparedness, as Australian species adapt to new environments – and those environments adapt to
the introduced trees.

ACIAR has two major projects underway in South-East Asia to improve forestry biosecurity practices and build capacity. Another project in Ethiopia has moved to quickly assess a devastating new threat wiping out an acacia species that has become integral to community life.

Risks in South-East Asia

The University of Tasmania is leading the project ‘Managing risk in South-East Asian forest biosecurity’ to improve the tools and technologies available for good forestry biosecurity practices in the region. Indonesian and Vietnamese researchers and plantation stakeholders are collaborating on this project.

The project aims to improve knowledge of pests and pathogen risks, increase disease tolerance through tree breeding, and evaluate technology and other resources to improve surveillance for pests and diseases.

Technological resources being evaluated include the use of uncrewed aerial systems to detect symptoms of pests and diseases in plantations. It also includes modelling that examines the effects of climate change on host species and the distribution of its pests and diseases.

three men in a eucalyptus plantation in cambodia
Forest surveillance in a eucalyptus plantation in Cambodia. Photo: University of the Sunshine Coast

Working on the project in Indonesia is Dr Anto Rimbawanto, at the Research Center for Plant Conservation, Botanic Gardens and Forestry, National Research and Innovation Agency. He said the ACIAR-supported project is highly valuable because of the emphasis on improving scientific capacity and the impact of research on the community and smallholders.

The cross-disciplinary research has helped to create strong partnerships between the public and private sectors.

‘Industry partners are a crucial part of the project,’ said Dr Rimbawanto. ‘The ones facing the problem head-on are the plantation managers. They have a very good team of forest pathologists to help solve this problem, and the ACIAR-supported project helps reinforce the capacity of their team.’

This will also be important to smallholders, as the industry will need to introduce the knowledge obtained from this project to smallholders to strengthen the country’s capacity to respond to biosecurity threats to plantations.

Breeding for resistance

Indonesia has one of the biggest pulp plantation industries in the world, and for many years has relied heavily on Acacia mangium plantations.

However, a major infestation of the fungal diseases Ganoderma and Ceratocystis devastated both large and small plantations of Acacia mangium across the country within a few years. Acacia plantations in Vietnam also suffered significant losses to Ceratocystis.

As the vulnerable Acacia mangium was replaced with another Australian species, Eucalyptus pellita, the current project includes tree breeding as part of a preventative approach.

Dr Jeremy Brawner, University of Florida, leads this part of the project, working to identify existing diseases to which eucalypts may be susceptible in Indonesia, Vietnam and Laos.

landscape photo of green and yellow crop fields in ethiopia
Acacia mearnsii agroforestry plantings in Ethiopia. Photo: University of the Sunshine Coast

‘This consists primarily of setting up trials with partners across South-East Asia to work towards an understanding of the pathogens’ limits and which eucalypt populations are most affected. Getting that network organised has been a big part of the project,’ said Dr Brawner.

Knowing what diseases are out there allows his team to test the susceptibility of Eucalyptus pellita and other species before outbreaks occur, and to identify germplasm with resistance that farmers can use in future plantations.

Building networks

This risk management project feeds into another ACIAR-supported project, ‘Building an effective forest health and biosecurity network in South-East Asia’, which focuses on building capacity more broadly across the region. Project leaders are Associate Professor Simon Lawson and Dr Madaline Healey at the University of the Sunshine Coast.

It follows previous ACIAR-supported forestry projects with partners in Laos, Thailand, Vietnam and Cambodia over the past decade that identified the value of a collaborative approach between countries in controlling invasive insect pests and pathogens.

Dr Healey explained that although there are trans-border biosecurity protocols for some agricultural produce, such as rice and vegetables, there have been few formal processes related to forestry biosecurity risks. ‘The idea is to connect with and expand on these existing agricultural biosecurity protocols and resources in a joined-up approach.’

man in front of a pile of black wattle sticks
Charcoal production in Ethiopia has been threatened by a disease affecting Acacia mearnsii. Photo: University of the Sunshine Coast

‘Sharing information, resources and technical capacity allows these countries to be prepared for what pests might turn up in their forests,’ said Associate Professor Lawson. ‘Collectively, they can then share their capacity to contain or eradicate any pests or pathogens that come in.’

The project research team initially analysed the capacity of the 6 partner countries (Cambodia, Indonesia, Laos, Malaysia, Thailand and Vietnam) to identify where help may be needed, such as in the diagnostics or policy fields. Ground surveillance and trapping is also underway to get a better picture of existing pests and pathogens.

Dr Quang Dao Ngoc, Forest Protection Research Centre, Vietnamese Academy of Forest Science, is the project coordinator for Vietnam and said his staff are building their skills through involvement in the surveillance program.

‘They are able to identify high-risk sites, and improve their sorting, triaging and diagnostics skills. We benefit from project outputs such as increased awareness of invasive forest pests and diseases and their negative impacts on forest industries and the environment, and also obtain protocols for pest and disease management,’ said Dr Dao Ngoc.

Disease diagnosis in Ethiopia

Diagnostics has been central to an ACIAR-supported project in Ethiopia, where the introduced Australian Acacia mearnsii has established itself as a species of significant ecological, economic and social importance. In recent years, it has been devastated by a disease that has wiped out smallholder plantations.

Dr Nora Devoe, ACIAR Research Program Manager, Forestry, said when the outbreaks were reported in 2021, ACIAR initiated a project to help local organisations identify what they were dealing with to better plan their response. This project was also led by Associate Professor Lawson and Dr Healey.

‘We were contacted by our colleagues in Ethiopia who said there’s some disease happening and it’s almost decimated the whole value chain of acacia,’ said Dr Healey. ‘That includes the farmers who grow it, to the people who use it for charcoal production, to the transport workers who transport the charcoal, to women who now have to walk much further to try and find firewood.’

In Ethiopia, Acacia mearnsii has become known as ‘black gold’ or ‘black sesame’ due to its many uses, as forage feed for livestock, as charcoal and fuel wood, and as a soil improver that helps to fix nitrogen. It also provides local economic and job opportunities, reducing the need for regional migration.

After being introduced from Australia in the 1990s, it grew relatively untroubled for many years, before its pests and diseases also began to find their ways to Ethiopia.

While trying to identify the disease, researchers also realised that the imported tree species had been misidentified as Acacia decurrens. Through collaboration between the Ethiopian Environment and Forest Research Institute, and the Forestry and the Agricultural Biotechnology Institute, based in South Africa, it was re-identified as Acacia mearnsii. This helped to diagnose the disease as Uromycladium acaciae, a type of wattle rust.

Associate Professor Lawson said the next steps for Ethiopia will include biosecurity initiatives to prevent the spread of disease and assessing management options in affected areas, along with preparation of management strategies to counter other invasive pests and pathogens. 

ACIAR PROJECT: ‘Managing risk in South-East Asian forest biosecurity’ (FST/2018/179), ‘Building an effective forest health and biosecurity network in South-East Asia’ (FST/2020/123), ‘Management of Acacia decurrens Pests and Diseases in Ethiopia’ (FST/2021/162)