Economically profitable post fire restoration with black truffle (Tuber melanosporum) producing plantations

Cultivating black truffle (Tuber melanosporum Vittad.) is highly profitable in sites suitable for its development. Land use history is an important factor when choosing suitable habitat, and lands with non-ectomycorrhizal host species are recommended when introducing T. melanosporum-inoculated seedlings in order to reduce competition from native, soil-borne ectomycorrhizal (ECM) inoculum. Nearly every year Mediterranean wildfires cause the loss of forested lands where soil and climatic characteristics are suitable for truffle cultivation. Introducing T. melanosporum-inoculated seedlings in these sites could promote reforestation with a native ECM fungus and, in addition, may provide economic incentives. We tested the viability of burnt forest lands for truffle cultivation by introducing T. melanosporum-inoculated Quercus ilex seedlings in burnt forest sites with and without resprouting forest species which act as repositories for native ECM fungi. We also evaluated the role of the ECM host plants, which resprout after a forest fire, in the maintenance and dynamic processes of the ECM fungal community. The study followed a factorial design with two levels: (1) T. melanosporum-inoculated and non-inoculated Q. ilex seedlings and (2) presence and absence of ECM host plants resprouting after the fire. We established 10 experimental plots with 360 holm oaks. After four and a half years, the truffle-inoculated holm oaks maintained 36 % of their root tips colonized with T. melanosporum, and 10 years after plantations, 26.2 % of the surviving inoculated holm oaks displayed a "truffle burn" area. A greater ECM morphotype richness was associated with seedlings planted in plots with the presence of ECM host plants, whereas the T. melanosporum mycorrhizal ratio was constant. These results suggest that reforestation with T. melanosporum-inoculated seedlings can be successful following forest fires and highlights the competitiveness of this fungus within the ECM community in these soils.