Maximizing Log Based Shiitake Mushroom Production by Determining Optimal Fruiting Conditions
Nicholas Laskovski, owner/founder of Dana Forest Farm and Bridgett Jamison, Graduate Student at UVM have collaborated to perform on-farm research at Dana Forest Farm in Waitsfield, VT.
The research goal will seek to provide optimal fruiting times and conditions for the production of log-based shiitake mushroom cultivation.
In the first year (2011), our research tested several methods for determining mycelial colonization and moisture levels within inoculated shiitake logs (aka bolts).
In 2012, we continued our colonization research as well as created time trials for full water immersion of logs (aka shocking) to ‘force fruit’ shiitake from incoulated logs. By trying to understand exact length of time for shocking (0 hours, 6 hours, 12 hours, 24 hours, 48 hours) farmers will be better able to manage their shiitake laying yards and optimize timing for efficient production and market availability.
Ultimately, our goal is to determine conditions which will allow for increasing shiitake yields. By increasing yield, our research will allow current log based shiitake farmers to save time and money while increasing farm revenue. New or upcoming shiitake farmers could justify adding or increasing log-based shiitake cultivation to their current farm or forests, ultimately diversifying operations, creating a more sustainable economic future for farmers of the Northeast.
In the spring of 2011, I felled thirty sugar maple trees. Trees were cut into three-foot lengths generating 500 three-foot long logs with a diameter between 4 and 6 inches. The bolts were inoculated on either 4/17/11 or 5/1/11 following standard procedures. 100 logs were randomly selected for the experiment. Each log was labeled using a durable metal tag. Initial log weight, diameter, and length were recorded. 2011 sampling dates and summary are provided in the 2011 Annual Summary.
We sampled these logs again on May 20th and August 11th, 2012.
Time trails for shocking began at 12:00 on September 1st, 2012 (48 Hour Shock). Subsequent shockings occured at; 12:00 September 2nd(24 Hour Shock), 23:59 September 2nd (12 Hour Shock), 06:00 September 3rd (6 Hour Shock), and 12:00 September 3rd (0 Hour Shock). All logs were removed from our pond between 12:00-12:15 on September 3rd and placed in fruiting stacks under the same shaded conditions.
Because of colonization and timing, we were only able to provide one shocking treatment for our experimental logs. Results are provided in the attached graph. It is known that Year 2 and Year 3 produce higher volumes of shiitake than year 1. Post inoculation, the same logs are able to bear shiitake mushrooms for up to 5 years with repeated shockings – usually 2 shockings per year. (I have personally seen logs fruit shiitake mushrooms up to 10 years after inoculation).
• Sampled logs to determine log weight and tricoderma severity on May 20th, and Aug 11th. Samples from each log were dried for 72 hours and re-weighed to determine moisture content and density.
• Logs were randomized and shocked on September 1st-3rd. We tested four commonly employed shocking durations (0 hr, 12 hr, 24h, and 48 h).
• Sections of each log obtain from the August 11th sampling event were treated in a 1% solution of Bromophenol Blue (BPB). The proportion of log stained blue was contained against the proportion of log stained yellow using digital image analysis (DIA) (ImageJ Software). Using this information, we calculated the percent of shiitake mushroom colonization on each log.
• Mushrooms were harvested on September 15th from each log. The number of shiitake mushrooms produced by each log and the fresh weight of the mushrooms were recorded.
There was no relationship between the amount of shiitake mycelium colonization estimated using digital image analysis of the BPB treated sections and the shiitake production. Therefore, we can conclude that a BMP treatment cannot be used to predict when a log is ready to fruit (See Figure “BMP Treatment and Shiitake Production (Correlation)”. Interestingly, the amount of shiitake mycelium colonization estimated using digital image analysis of the BPB treated section could be used to successfully predict the log density. Therefore, we know the BMB treatment can accurately measure the rate of mycelium colonization. (See Figure “DIA and Density”)
We determined that the duration which a log is soaked/shocked impacts the shiitake production. Logs dunked repeatedly by never soaked produced significantly less shiitake mushrooms that logs soaked for 24 hours. The greatest yields of mushrooms were on log soaked for 24 hours. (See Figure “Shocking Duration and Production”)
By tracking the change in log density over time, we were able to estimate the rate of mycelium colonization over time. Our results showed that the rate the bolt density change was not correlated to production. We also plotted the total percent change in density over two years against the shiitake production. There was no relationship (See Figure “Percent Loss and Production”.) These results indicated that shiitake production is not related the rate of mycelium colonization.
During the beginning of the study, we measured the diameter of each log. We used this information to calculated the surface area of the end of the log. We plotted this information against the shiitake production in order to determine if there is a correlation between log size and production. Our results showed there was no relationship between log diameter and total shiitake mushroom production (See Figure “Diameter and Production”)
- BMP Treatment and Shiitake Production (Correlation)
- Shocking Duration and Production
- Percent Loss and Production
- Diameter and Production
- DIA and Density
Impacts and Contributions/Outcomes
One more season of shocking logs (essentially two more times) would strengthen shocking data and provide more samples to add significance. The costs for the extension would be minimal and would only add for time. As mentioned above, Year 2 and Year 3 logs post inoculation produce more mushrooms than Year 1 logs. This is known to be because of mycelial colonization, being greater in the older logs. We believe stronger fruitings coupled with more trials will show us more significant results and provide a better analysis for farmers.
Outreach and publications, primarily to Northeast Mushroom Growers Network.
Summarize data for final reporting.
University of Vermont
Burlington, VT 05405
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