Relationship between climate, expansion rate, and fruiting in fairy rings (‘shiro’) of an ectomycorrhizal fungus Tricholoma matsutake in a Pinus densiflora forest

Abstract

Abstract Tricholoma matsutake is an economically important fungus in Japan. Its basidiocarps occur in groups called shiro. Little is known about the relationship between the expansion rate of shiro and the number of basidiocarps or meteorological factors. When data from an 18-yr survey were analyzed using a hierarchical Bayesian framework, the expansion rate was estimated to be 0.17 ± 0.01 m yr−1. Positive correlations were found between the expansion rate and the number of basidiocarps, mean air and soil temperature, and total precipitation. Similarly, there was a positive correlation with an index of accumulated warmth, termed WI20, especially in the pre-emergence season. The Akaike information criterion (AIC) of linear models decreased when precipitation was excluded as an explanatory variable. Furthermore, mean air temperature and WI20 showed positive correlations with the number of basidiocarps. These results suggest that the effect of temperature in the pre-emergence season is greater than that of precipitation with respect to the expansion rate of shiro, which in turn affects the numbers of basidiocarps.