Insights into the dynamics of Boletus edulis mycelium and fruiting after fire prevention management

Abstract

Boletus edulis Bull. is among the most valuable mushroom species worldwide. Cistus ladanifer L. scrublands host an extraordinarily high production of this profitable fungus. Its fructification varies greatly among years depending on factors such as stand age and density along with climatic variables. Important information is missing, however, on the dynamics of this species, particularly at the below-ground level and its correlation with sporocarp production. We sought to improve understanding of the ecology of this species that could allow prediction of B. edulis production using faster and less expensive procedures under forest management scenarios.Under the hypothesis that fire prevention management influences the presence of Boletus edulis mycelium and thus, the production of sporocarps, different management treatments were performed. These consisted of different levels of fuel reduction: (controlled burning, total clearing, 50% clearing, and uncleared), established in scrublands of different ages/origins (young-fire, young-cleared and senescent). To analyse B. edulis mycelium in the soil, soil samples were taken at three different times during the year, quantifying B. edulis DNA by real-time PCR using specific primers and Taq-man probes. To analyse B. edulis production, all sporocarps were collected and weighed on a weekly basis during the autumn season.Our results confirmed that management significantly influence quantities of B. edulis mycelium in soil and sporocarp yields that were highest in the uncleared plots and lowest in total clearing plots. Fifty percent clearing plots showed a significant recovery for both mycelium quantity and B. edulis yields after three years.Concerning the origin of the stand, young-fire plots had the highest amounts of B. edulis mycelium in the soil. A positive correlation was detected between B. edulis fresh weight production and the amount of mycelium in the soil suggesting the ability to predict B. edulis yields using faster and less costly methods than weekly inventories carried out for several autumn seasons.