HARDWOOD logs destined to rot on the forest floor are proving a suitable host for one of the world's most popular mushrooms.

Shiitake mushrooms are being grown in logs harvested from the Otway Ranges in southwest Victoria.

    AT A GLANCE
  • Who: Rob Wertheimer and Matt Armstrong
  • What: shiitake mushrooms
  • Why: adding value to logs
  • Where: Wongarra

The logs are about a metre long and 8-15cm in diameter and have holes drilled in them to hold dowels containing mycelium and then sealed with beeswax.

They are then stacked away for nine to 12 months in controlled conditions, in readiness for the first crop of mushrooms.

Traditionally grown in Asia on oak logs from the shii tree (shiitake means oak mushroom), shiitake mushrooms are highly prized for their rich  flavour and health-giving properties.

Otway Forest Shiitake, at Wongarra, is run by Rob Wertheimer, Matt Armstrong and Mike Edwards, members of the Otway Forest Network with a common interest in agroforestry.

Rob said the group was looking for innovative ways to make growing trees on farms more profitable.

"We realised our thinnings from hardwood had potential value for growing shiitake," Rob said.

The trio is the only commercial producer of fresh shiitake grown on logs  in Victoria.

They were introduced to shiitakes by Parsuram Sharma-Luital a former extension officer in Bhutan who is now working in Australia.

Parsuram developed the first commercial-scale log-grown shiitake enterprise in Australia and sold mushrooms directly to the wholesale markets as well as to restaurants.

He teamed up with senior fellow in forest science at Melbourne University, Rowan Reid, to demonstrate that some farm-grown eucalypts could be as productive as oak.

The pair produced a booklet detailing the methods, yields and prospects for log-grown shiitake mushrooms in Australia.

Rob said their initial interest was sparked by Parsuram in a workshop organised by Rowan.

"Parsuram has been incredibly generous with his support and information, as have Rowan and the network," he said.

Matt said Otway Forest Shiitake started shade-house trials in 2008 and was now going to full commercial production.

"We are building a facility to grow shiitake year-round by reproducing a forest environment in polyhouses," Matt said.

"Shiitake are not hard to grow but they must be controlled to produce good commercial yields - too wet and you will get competing fungus, too dry and you will kill the fungus."

The group has found that while mushrooms will basically grow on any hard wood, some woods, such as shining gum and sugar gum are better than others, such as spotted gum.

Rob said it all depended on the moisture content of the bark.

"If the bark is too thin they dry out too quickly and if the bark is too thick the pinning of the mushroom can't get through," he said.

Rob said they were getting about four harvests a year.

"The mycelium spawn must run through the log so it needs that time to grow and inhabit the whole log," he said.

"Then we induce the fruit by dunking the log in cold water for 24 hours - the Japanese sometimes beat the logs as it emulates the dropping of the dead limb on to the forest floor, and they are also supposed to respond to lightning, thunder and rain, which induces fruiting."

After sealing, the logs are placed vertically on racks for ease of harvesting and to produce a better-shaped mushroom.

Depending on conditions the crop is ready  in one to three weeks,  and after the mushrooms have been harvested the logs go back on to the stack for another three months, when the process starts again.

While shiitake production from eucalypts is still in its infancy, Matt said they were confident they had a great product.

"The challenge is to make it profitable, as we want to make a living from it," he said.

"The ease of growing shiitakes in sawdust is why everyone does it, but we came to this through the agroforestry connection and that's what excites us as we also have a very strong interest in promoting trees on farms.

"In Japan sawdust-grown shiitake is seen as a cheaper product with consumers paying $20-$30/kg, but for taste they go to the log-grown which brings $100-$200/kg." .

Matt said they were producing about 30kg of shiitake a week, however this would increase as more logs reached the production stage.

"We are mostly marketing through restaurants as chefs appreciate the taste difference of the log-grown shiitakes," he said.

"As for returns, at present it is just too early to tell, however we are encouraged by the positive acceptance of the product so far."