Maximizing Log Based Shiitake Mushroom Production by Determining Optimal Fruiting Conditions

Project Overview

Project Type: Farmer
Funds awarded in 2011: $12,143.00
Projected End Date: 12/31/2014
Region: Northeast
State: Vermont
Project Leader:
Nicholas Laskovski
Dana Forest Farm
Bridgett Jamison
University of Vermont

Annual Reports


  • Miscellaneous: mushrooms


  • Crop Production: agroforestry
  • Education and Training: farmer to farmer, on-farm/ranch research
  • Energy: energy conservation/efficiency
  • Farm Business Management: risk management
  • Natural Resources/Environment: indicators
  • Production Systems: organic agriculture, permaculture
  • Sustainable Communities: sustainability measures

    Proposal summary:

    Nicholas Laskovski owner/founder of Dana Forest Farm and Bridgett Jamison, Graduate Student at UVM will collaborate to perform on farm research at Dana Forest Farm in Waitsfield, VT. The research will test several methods for determining mycelial colonization and moisture levels within inoculated shiitake logs. This research will seek to provide optimal fruiting times and conditions for the production of log-based shiitake mushroom cultivation. 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 forest, ultimately diversifying operations, creating a more sustainable economic future for farmers of the Northeast.

    Project objectives from proposal:

    Shiitake mushrooms can be produced on either whole natural logs or an artificial substrate often composed of sawdust and agricultural waste products. The latter method produces a greater yield of mushrooms per unit volume substrate, in a shorter period of time. Growing shiitakes on whole logs is more labor intensive and has a lower Biological Efficiency (B.E). However, there has been a resurgence of interest in cultivating shiitakes on whole logs, because of certain small scale advantages. Log based mushroom production is well-suited to a broad range of land management objectives and can be a profitable method of diversifying income using low-value forestry by-products (Bruhn et al. 2009). Compared to sawdust substrate procedures, the log growth method is simpler and less expensive. It requires less energy input and is more environmentally friendly. In terms of product quality, on average log grown shiitake mushrooms contain more high weight molecules proteins (HWMP) like lentinan, which may promote human health (Brauer et al. 2002).

    Despite the advantages of log-based production, growers are frustrated by the lack of standardization. We are specifically interested in investigating the final stage in shiitake production during which growers “shock” logs by submerging them in water in order to encourage fruiting. Variables that have been shown to dramatically impact production rates are: the degree of colonization by mycelium, the difference in water vs. air temperature, and the ratio of water to air in the log following shocking. Growers can estimate mycelial growth through a visual assessment of the log end or by drying and weighing logs to determine changes in dry density. The air to water ratio can only be measured in a laboratory setting. These methods are either impractical or too subjective to be valuable to most growers.

    We propose to investigate how these three variables affect shiitake production by developing a simple method for growers to implement the improved methodology. Measuring the pH of the log may be an easier and more reliable means of estimating mycelium maturity in the field. I intend to test if Bromophenol Blue (BPB) can assess log decay in the field and predict the optimal time to induce fruiting. If successful, this procedure would be very valuable to growers in its ability to providing a method to detect fruiting potential and evaluate flush timing for each log. I also propose using the information from this and other related studies to generate a simple online tool fact sheet which uses variable of log pH, age, tree species, shiitake strain, and decay rate to estimate the appropriate shocking procedure. This will reduce guesswork by growers – a cause of profit loss and continued frustration.

    Experimental Overview
    This will be a random block design study with ten replicates per treatment studying the effect of the two variables [Degree of mycelium colonization (four treatments) and duration of soaking (four treatments)] on shiitake production. It will also investigate the relationship between the age of the log and degree of mycelium colonization as measured by change in density and pH. The goal is to develop a simple and reliable method for small-scale growers to maximize production.

    Inoculation Methods
    In the spring of 2011, I will fell thirty sugar maple trees. I will cut the trees into three-foot length generating 500 three-foot long logs with a diameter between 4 and 6 inches. I will inoculate the logs in the spring following standard procedures. 160 logs will be randomly selected for the experiments. Each log will be labeled with a durable metal tag. Initial log weight, diameter, and length will all be recorded. An increment borer will be used to remove a core sample from each log. Holes from core samples will be filled with a wooden dowel to avoid contamination. The core sample will be weighed and then oven dried at 105 degrees C for 24 hours to determine the gravimetric moisture content. Using this information I can estimate the initial dry weight of the log. Logs will be randomly stacked in my laying yard. I will then allow the mycelium to colonize the log following standard procedures.

    Mycelium Colonization
    Every six weeks during the mycelium colonization period, we will measure the density, weight, moisture, and pH of the each log. Weight will be measured using a portable digital scale. Percent moisture will be determined as the percent weight loss from a 5 centimeter core after 24 oven drying. This true value will compared to the value given by the moisture meter. Density will be determined as the weight of the oven dry core divided by the volume. Analysis will be performed at laboratories at the University of Vermont by graduate student, Bridgett Jamison. pH will be measured in two ways: (1) by applying a dilute solution of BPH to a one square inch area at the end of the log and (2) by using a power-drill to drill remove teaspoon of wood shavings from a random location in the log a spraying them with a dilute solution of BPH. We will photograph the resulting color and record it using the Munsell Color scale.

    Timing of Spawning
    Logs will be randomly divided into four groups. Group will be shocked at six week intervals beginning one year after inoculation (2012). Prior to being shocked, logs will have their density, weight, moisture and pH measured one last time.

    Water Content Post Shocking
    We will attempt to eliminate the air temperature and water temperature by shocking the logs when the air temperature is between 20 and 25 degrees Celsius. We also will standardize the temperature of the water between treatments to 5 to 10 degrees Celsius by adding ice if necessary. Water and air temperature will be continually monitored using waterproof data loggers. Logs will be randomly divided into four groups to be subjected to four durations of soaking: 6 hours, 12 hours, and 24 hours and 48 hours. Upon being removed from the water, they will be immediately reweighed in order to determine the free water content and mass of water absorbed.

    Shiitake Production Efficiency
    Logs will then be stacked for fruiting. Mushrooms will be collected every day at the same time each day. Total mass of mushrooms obtained per log will be calculated. A few representative mushrooms will also be used to determine the mass moisture content of the mushrooms.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.