Forest farming of shiitake mushrooms – a scientific article

The following article discusses and compares and contrasts yields on oak and maple logs under various management regimes.  It is available from Science Direct for $41.95.  Below we show the abstract and table of contents.

Forest farming of shiitake mushrooms: An integrated evaluation of management practices Original Research Article

Bioresource Technology, Volume 100, Issue 24, December 2009, Pages 6472-6480 J.N. Bruhn, J.D. Mihail, J.B. Pickens


Two outdoor shiitake (Lentinula edodes) cultivation experiments, established in Missouri USA in 1999 and 2000, produced mushrooms in 2000–2005. We examined shiitake production in response to substrate species, inoculum form, inoculum strain, and inoculation timing, using total mushroom weight per log as the primary response variable with log characteristics as covariates. The significantly greater mushroom weight produced by sugar maple logs compared with white or northern red oak was attributable to the higher proportion of undiscolored wood volume in the maple logs, rather than to bark thickness or log diameter. The “wide temperature range” shiitake strain produced significantly greater yield compared with the “warm” or “cold” weather strains. Both the wide-range and warm-weather strains were stimulated to fruit by significant rain events, while the cold-weather strain was responsive to temperature. Inoculation with sawdust spawn gave significantly greater yield than colonized wooden dowels or pre-packaged “thimble” plug inoculum. The second and third full years following inoculation were the most productive.

    Article Outline

Authors’ Conclusions:

“In summary, based upon these studies we can recommend some management guidelines for shiitake growers in the central US focused on natural precipitation-induced fruiting.  Growers should begin by selecting trees with a minimum volume of discolored wood (typically rapidly growing tress or branch wood of larger trees).  Our trials show that sugar maple is superior to either white or northern red oak as a substrate species.  If sugar maple is available, it can be harvested as early as February and stored under shade.  In contrast oak logs can be harvested shortly before early spring inoculation.  Inoculation using a wide-range shiitake strain in the form of traditional sawdust spawn is most likely to provide the greatest yield under the broadest range of environmental conditions.  While larger logs will continue to fruit for at least six years after inoculation, most logs will be most productive during the second to fifth years following inoculation”.

Our Comments:

Note that the authors consider sugar maple to be ‘superior’ to oak based on yield and not on the quality of the mushrooms nor the lifespan of the log. In their analysis the authors attribute this to the fact that the maple logs had a higher proportion on ‘un-discolored’ wood volume (more vulnerable to decay by the shiitake fungus) than the oak logs did and not because the maples have larger conserves of reserve carbohydrates. This seems to indicate that it is important to cut from healthy trees that do not have a high proportion of discolored heart wood.

The authors advise growers in the central US to cut sugar maple no earlier than February and that oak can be cut shortly before early spring inoculation. The authors go on to explain that “of the three host species [white oak, red oak, and sugar maple], only sugar maple productivity was enhanced by early harvest and aging of substrate logs.  We suggest that this effect is due to earlier sap-run in sugar maples than in oaks“.  However, our experience and the experience of other growers tells us that logs of all species can be cut during a wider timeframe – November to March. Furthermore, information from many other sources indicates that logs should be cut after leaf fall in the autumn and before leaf bud in the spring and also that the bark is tighter on the wood when the temperature is very cold (January /February).  Based on this disparate information we, in Canada, recommend:

1. that logs from any species should be cut from healthy trees;

2. that most species, including oak, can be cut any time from beginning of December to beginning of March;

3. that maples should be cut earlier from beginning of December to beginning of February.