The relationship between the wood properties and decay levels of Pecan logs

Peiyao Zhang, Gereald Riskowski


The objective of this research was to find a solution for how to define and determine the decay levels of Pecan logs. Ultimately this information could be used to determine the preferred decay level of Pecan logs for Auricularia auricular-judae (wood ear mushroom) growth.  Previous research had found some relationship between densities and C/N ratio of hardwood boreal trees in Canada. In this research, the physical (density, moisture content, penetration depth, etc.) and chemical properties (carbon, nitrogen and C/N ratio) of logs were measured from pecan logs at different levels of decomposition. First, the traditional visual method was used to define the decay level and they were compared to the log physical and chemical properties to find relationships between them. There was a negative relationship between log densities and decay levels. The more decayed logs had lower densities than new, fresh logs. Densities could be used as a basic standard to represent log decay levels. When the densities of logs were less than 430 , the negative relationship was significant between penetration depth and densities of logs. The relationship between C/N ratios and densities of logs was not significant, except for logs that already had mushroom fruiting residue present. Therefore, there was some relationships between log properties and decay levels. These log properties can be useful as parameters to determine the decay level and select the logs with the right decay level for Aricularia mushroom growth.


Auricularia auricula-judae, Pecan logs, wood decay level, carbon, nitrogen

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