Australian Log-Grown Shiitake Mushrooms

The cultivation of shiitake mushrooms on oak logs (Quercus spp) has been practiced for centuries in China and Japan. In fact, the word Shiitake literally means Oak-Mushroom . The fungus colonises dead timber then fruits in response to moisture. Field based production of Shiitake on logs is now relatively common practice amongst North American forest owners. Inoculated logs are stacked in the forest to rest then repeatedly treated to stimulate fruiting. A single oak log can be produce mushrooms for up to 4 to 5 years.

I was introduced to Shiitake production by a past student, Parsuram Sharma-Luital. Parsu came to Australia from Bhutan to study for his Masters in Horticulture but is now an Australian resident. Parsu has brought with him a wealth of knowledge, skill and enthusiasm. Back in Bhutan he'd worked with farmers growing mushrooms, including Shiitake.

Research undertaken in the northern hemisphere suggests that Oak (Quercus spp) is the most productive and resilient species for log-based mushroom production. Other species that have been successful include Alder (Alnus spp) and Birch (Betula spp). The fungal mycelium spreads under the bark and throughout the sapwood of the logs. Characteristics that appear to be important are the ability of the log to retain moisture, the bark type and its persistence, and the starch content of the sapwood. There are reports of Shiitake being grown on eucalypts in South America but we know of no examples in Australia .

Parsu with oak logs

With many landholders now establishing and managing plantations for sawlog production there is clearly interest in the potential for using eucalypt thinnings. If this can be done cheaply, on-farm, shiitake mushrooms may provide a useful early commercial return for forest owners growing sawlogs. At CERES we are trialling the production of Shiitake on English Oak (Quercus robur), Shining Gum (Eucalyptus nitens), Sugar Gum (E. cladocaylx), Poplar (Populus hybrid spp), Common Alder (Alnus glutinosa) and Blackwood (Acacia melanoxylon). What follows is a report on our early observations.

Production method

During the winter of 2006 hundreds of fresh logs (approximately 10-15 cm in diameter and about 1m in length) of six different tree species were harvested from two agroforestry farms in Victoria . The logs were stored for short time prior to inoculation in late winter/early spring with Lentinula edodes spores sourced from overseas. The inoculation involved drilling holes into the sapwood (at approximately 10cm intervals) and inserting of an infected wooden plug. Bees wax was poured over the hole to provide a seal and wax painted on the ends of the logs to reduce drying. The logs were then stacked in a shade house and regularly watered over the summer months.

In mid autumn the logs were soaked for 24 hours to stimulate fruiting then stood up in racks. Within 4 or 5 days small growths appeared on some of the logs. This process is called “pinning” and signals the formation of mushrooms which then develop over the next few days. Once they are fully open the mushrooms are picked and sold fresh into the CERES market or to the local restaurant.

Whilst Oak has proved the most productive, yields from other species are encouraging. One Alder log produced more than 20 mushrooms! Shinning Gum and Sugar Gum look promising but there is a risk that the bark will be less persistence than the Oak and may crack open exposing the mycelium to dry air. Although Blackwood has a tough oak-like bark, the mycelium growth and mushroom production appears to be slower than for Oak.

Once fruiting is complete the logs are stacked again to rest. It is expected that it will be possible to repeat the process of soaking and fruiting every 2 months for up to 4 or 5 years. We will monitor the performance of all the species over the next year or more.

The trial has certainly demonstrated that it is possible to produce marketable Shiitake mushrooms on logs in Victoria and that it may be feasible for farmers to set themselves up for small scale production. All that is required is a supply of logs, a cool-shaded area under a canopy or shade cloth, and the ability to regularly spray the logs to keep them moist. Whilst this final point may be wishful thinking for many during a drought many farmers have moist areas on the properties where they might be able to recycle the water.

Eucalyptus nitens (Shining Gum)

The future

Parsu and I are keen to explore the potential of farm-based log production systems in Australia . We want to test a range of strains on the logs of other tree species and production methods. Based on our experience and production overseas, we believe there is potential for log-based Shiitake production to be viable in both temperate and sub-tropical areas..

We also hope we can get funding for a major research trial that includes the provision for training and networking with growers. Shiitake production has the potential to develop into a large and diverse industry the feeds into local, state and international markets. There is much to learn.

In addition to suitable logs, growers need access to water and be able to regularly monitor the logs and harvest the produce. The higher the humidity the better suggesting that up the east coast farmers with dense forest cover maybe able to set up production areas in existing forest using local native timber species Readers who are interested in learning more are welcome to contact us. We'll add you name to an email list to provide regular updates and information. If there is sufficient interest in your region we may be able to run a training day for growers.

For details contact me on rfr@unimelb.edu.au

Acknowledgment

The Shiitake been grown by Parsu in Melbourne are part of the CERES Organic Mushroom project which is an AMES-CERES social enterprise involving new migrants from the Karen (Burmese) Community and supported by Victorian Government funding. The CERES Community Environment Park is in Brunswick : www.ceres.org.au