6 Wood Discoloration

240 9 Positive Effects of Wood-Inhabiting Microorganisms
in Asia. The name Shii-take means “Pasania-fungus”, because the mushroom
was grown on the “Shii-tree” (Castaneopsis (Pasania) cuspidata, Japanese chinquapin).
For the cultivation of this excellently tasting mushroom (compared
to the Shii-take, the commercially produced agarics taste like nothing) as “natural
log cultivation”, originally in China, and later in Japan, logs and branch
sections were exposed to natural, passive inoculation by wind-borne spores
and were stacked in the forest for fruit-body formation. About 300 years ago,
the Shii-take was cultivated by farmers for extra income to be sold on local
markets. The bark surface of logs, particularly from Quercus serrata or other
fagaceous trees, was broken with an axe to improve the chances of inoculation.
Since the 1920s, pure spawn culture was placed (“spawning”) into holes
drilled into the logs. For the colonization phase of the substrate by mycelium,
the inoculated logs were first placed as stacks in the forest or in greenhouses
until the mycelium grew out. The colonized woods were then set up individually
or stacked crosswise in the forest (“growing yard”) or in greenhouses for
fruit body formation. Eight to 12 months after inoculation, there is the first
flush of mushrooms, and cropping of logs occurs over about 5 years. Since
the 1970s in Taiwan, Japan, and China, the Shii-take is produced commercially
on chopped wood (chips) and wood waste like sawdust under controlled
conditions such as defined substrate composition, temperature, light conditions,
relative humidity, and wood moisture content. The big breakthrough
for sawdust substrates was the use of plastic bags, in which the substrate can
be compressed, sterilized, inoculated, and grown out (Fig. 9.1). The woody
substrate is supplemented with amendments (bran, whole meal, urea etc.),
watered for a suitable moisture content, and inoculated with special isolates.
In this “bag” or “artificial log” culture, the mycelium knits the substrate into
a solid block. The methods for Shii-take production have been recently summarized
by Miller (1998). In the local experiments (Schmidt and Kebernik
1986; Schmidt 1990), different wood wastes such as chips (Fig. 9.1), sawdust,
Fig.9.1. Shii-take (Lentinula edodes)
fruit-bodies grown on wood waste chips
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