Beyond Bunya Dieback

Spencer and Karen Shaw, Brush Turkey Enterprises

In writing this, we acknowledge the Traditional Custodians of Bunya Country, the Elders past, present, and emerging and their biocultural connection with this country. This relationship has prevailed for tens of thousands of years, through ice ages, sea levels rises, and invasion. This connection always was and always will be.

Bunya is an English language interpretation of Bonyi/Bonyee/Bonye, the name given by the Traditional Custodians of Bunya Country – the Jinibara, Kabi Kabi / Gubbi Gubbi, and Wakka Wakka Peoples. The region we are referring to as Bunya Country is centred on the Blackall and Conondale Ranges (Sunshine Coast Hinterland, Queensland) and the surrounding catchments and then west to the Bunya Mountains – Bonye Biar.

Brief Bunya Backstory

Bunya, Araucaria bidwillii, is one of twenty surviving species from the family Araucariaceae. This Family is made up of three Genera, Araucaria (e.g. Bunya, Hoop, Norfolk Pine etc), Agathis (e.g. Kauris) and Wollemia (the Wollemi Pine). These trees have existed as an evolutionary lineage for 150 and up to two hundred million years. Current populations of Araucariaceae are only located in the Southern Hemisphere – Australia, Papua New Guinea, SE Asia, New Zealand, New Caledonia, and South America (in Chile, Argentina, Uruguay, and Brazil). However, the deep time archaeological record of fossil Araucariaceae records their presence across the globe. Interestingly the gemstone ‘Jet,’ collected from Whitby on the north coast of Yorkshire, England, is derived from the semi-fossilised timber of an Araucaria that appears to be closely related to Araucaria bidwilli.

Bunya only exists naturally in Queensland, with two tiny populations in North QLD, just inland from Cairns, and a scattered but larger population in SE QLD. These are the only ecosystems on earth where the Bunya still occurs naturally – a family of trees that were once widespread across the earth.

The Depressingly Dire Disease – Dieback

Healthy Bunya forest at the Bunya Mountains pre Dieback

Dieback is a global problem and widespread in Australia. It is a blanket term given to the mass death of trees and other vegetation from a variety of pathogens and other factors. Pathogen-based Dieback in Australia is often ascribed to one or more exotic/imported Phytophthora species. The word Phytophthora is derived from Greek ‘phyton’ plant, and the ‘phthora’ – destroyer, a rather apt scientific name. These organisms, although previously thought of as fungi, are in their own order of Water Molds. Phytophthora require water, wet soil/mud to complete their lifecycle and this is also how they can be spread – by mud or soil on feet, tyres or in water flow.

Plants impacted by Phytophthora species that you may be familiar with include Phytophthora infestans – Irish Potato Famine, Phytophthora agathidicida – Kauri Dieback, Phytophthora cinnamomi – many Australian natives and exotic fruit trees such as Avocado, Phytophthora multivora – Eucalypts in WA, Wollemi Pine in the Blue Mountains, and Bunya at the Bunya Mountains. Phytophthora’s mode of action is to enter the living tissue of plants, feed on and kill infected tissue, generally the roots and lower trunk. Due to root damage, the infected flora becomes more susceptible to climate change such as rainfall and temperature changes, and other pathogens such as fungi e.g. Fusarium. As a result of this infection, the whole plant can weaken and die rapidly.

Grove of Bunya progressively dying over a 2-4 year period

Bunya dieback was first recorded in SE QLD at the Bunya Mountains National Park, approximately 10 years ago. The harsh drought that ended at the beginning of 2020 saw the death of many ancient trees, some believed to be older than 800 years. As discussed already Phytophthora causes root damage and trees may appear quite healthy if rainfall is regular, however when dry weather occurs trees can no longer draw enough water and quickly die.

It appears Phytophthora multivora was introduced into this forest a decade or two back by movement of soil on shoes, vehicle tyres, and feral pigs. To address this issue, wash down stations to disinfect and remove soil from footwear and mountain bike tyres are now located at all track entrances. However, this could be argued as being a little too late as Phytophthora is now already present within and along tracks. On a positive note, hopefully these hygiene practices will educate the public and reduce the potential for the introduction of other pathogens in future. Raised boardwalks, or at least well drained tracks, and effective feral pig control will be needed to effectively address the spread and tree deaths caused by Phytophthora.

Closer to home for us on the eastern end of Bunya Country (Blackall Range and Sunshine Coast Hinterland) we first noted and recorded the presence of Bunya Dieback five years ago, with hundreds of trees dying over the last 5 years. In this region, death of Bunya is primarily occurring in remnant or planted trees in paddocks or rural residential land. For now, our forest trees are looking good, which leads me back to the other factors that are contributing to the demise of our Bunya.

Multicausal Malady

We know with ourselves, that if we are feeling run down or suffering from a poor diet, that we may be more susceptible and vulnerable to disease. It is the same with anything in nature, including trees. For example, on the Blackall Range, Bunya that are showing visible symptoms or have succumbed to Dieback are limited to trees in rural or rural residential areas. Bunya have evolved as a forest organism, and although through the lens of western society we tend to view all organisms as separate entities, they are of course intrinsically intertwined with the life they have evolved and co-operate with. In the case of Bunya, this has been over 100’s of millions of years. Just as we are learning the importance of gut health as crucial to our overall health, soil health is crucial for plants. So, it is with Bunya that are surrounded by lawn or paddock, that they find themselves in a situation that they have not evolved in, their overall health is reduced, and because of this they are more vulnerable to disease. Mown lawns and paddocks reduce top-soil depth and can become compacted.

What can we do about Phytophthora-induced Bunya Dieback?

  1. Hygiene. Reduce and prevent pathogen movement to new areas. This can be done by cleaning soil from your boots, tyres of vehicles and bicycles, particularly when you have accessed an area known to have dieback trees. After cleaning and removing soil the next step you can take is to apply a disinfectant such as methylated spirits and water (70:30) or household bleach (5% active ingredient) and water (20:80). The most crucial step is soil removal. If you skip this step and just apply disinfectants, this will not prevent pathogen movement.
  2. Even better than good hygiene, the best way to reduce soil-based pathogen movement is to reduce or eliminate access to areas with dieback or areas that may be vulnerable to infection. In Aotearoa – (the Māori name for New Zealand) where they are dealing with a similar pathogen causing dieback in Kauri Agathis australis, Māori communities instigate a temporary or long-term restriction of access that is called Rahui. This practice allows forests time to rest and prevent further spread. That said, access can be intrinsic to land management, so engineering works may be required, such as hard surface tracks, drainage, and boardwalks to permit all weather access, so as not to create or spread mud and soil.

  3. Paddock trees

    Soil Health. Soil health is rarely discussed with regards to dieback management in natural areas but is crucial in best practice management of Phytophthora in horticulture and agriculture. Most, if not all, the hundreds of Bunyas that have died on the Blackall Range over the last 5 years are located on rural and rural residential properties. Soils in these areas are often low in humus and the soil life that can boost the immunity of trees and keep them healthy and resistant to disease. Key steps here are to reduce access for vehicles and livestock during wet weather to prevent soil compaction; maintain high levels of organic matter in and on the soil e.g. leaving the ‘annoying’ prickly leaf mulch produced by Bunya under the trees. Mowing under trees removes this mulch and damages roots, further increasing risk of infection. Natural mulch/leaf fall should be maintained, and the addition of composted mulches could be trialled, as this is best practice management in Avocado Orchards to manage Phytophthora presence.

  4. Last, but not least, research and communication about the causes of dieback and best practice land management, hence our project Beyond Bunya Dieback.

‘Beyond Bunya Dieback’ Project… so far

In 2024 Brush Turkey Enterprises initiated a project called Beyond Bunya Dieback which is a platform to bring together Traditional Custodians, Bush Regenerators, Scientists, National Park Rangers, local Council and Utility Project Officers, Landholders, and Politicians. Our goal is to share knowledge, research, and management of Bunya Dieback, and more importantly Bunya Health. Why the name ‘Beyond Bunya Dieback’? Well, we drew inspiration from Tiakina Kauri, in Aotearoa, who refer to their Dieback management program as Kauri Ora (Kauri Wellbeing). As such we decided to give our project a name that focuses not so much on the disease, but on how we should focus on Healthy Country as the best way of managing this issue.

Karen and Spencer opening the 1st Symposium

 

So far, our activities have included the Beyond Bunya Dieback Symposiums in 2024 and 2025, with over a hundred people in attendance at each event. Knowledge holders from across Australia, Aotearoa/New Zealand, and California have shared their research about, and insights into how they are addressing their respective Dieback issues. The Symposia have achieved national media coverage and given us a platform to advocate to all levels of government with regards dieback issues in SE QLD. Stay tuned for the 2026 Symposium (planned for Friday 27th February 2026).

More recently we initiated and undertook pathogen testing at multiple Bunya Dieback sites on the Blackall Range, with the Jinibara Freshwater Rangers. Although Phytophthora multivora had been identified as the primary cause of Dieback in the Bunya Mountains by Department of Primary Industries (Queensland), on our sites neither Phytophthora multivora nor Phytophthora cinnamomi were identified in the first round of samples. Instead, two other exotic Phytophthora were identified, but these two species are not known (as yet) to be Bunya pathogens, so a lot more testing and research is needed.

More than ever, we need to look to First Peoples’ knowledge and wisdom and adopt wholistic management practices that focus not just on the problem e.g. weeds, feral animals, and pathogens that are eating away at ecosystems, but instead adopt practices that prioritise the regeneration of ecosystem health, whether that be biocultural burns or management of other degrading processes such as soil compaction, fragmentation, key stone species loss and so many more. For me, the death of iconic flora such as the Bunya is indicative of these wider ecological degradation issues. Bunya have been here for many millions of years, let’s make sure this species and thousands more don’t disappear on our watch.

Dead Bunya from above – Kim Herringe