Linkages between climate, seasonal wood formation and mycorrhizal mushroom yields

- Relationships between climate, wood formation and mycorrhizal fungi were analysed.
- Climate signal varied among tree ring features and fungal functional guilds.
- Mushroom yield mainly depended on summer water availability in the driest sites.
- Latewood formation is linked with mycorrhizal fungal yield in dry sites.

Fungi provide important forest ecosystem services worldwide. In Mediterranean pine forests, predicted warmer and drier conditions could lead to a decline in mushroom yields. Climate is a key factor regulating both tree growth and fungal yields, particularly in drought-prone Mediterranean ecosystems. However, the responses of forest growth and mushroom production to climate depend on the differences among tree and fungal species and functional groups (e.g., mycorrhizal vs. saprotrophic), forest types, as well as depending on site conditions. Here we investigate how climatic conditions drive seasonal wood formation (earlywood −EW− and latewood −LW− production) and mycorrhizal mushroom production, to disentangle if growth and fungal yields are related. This assessment was done in Mediterranean forests dominated by four pine species in two areas located in Catalonia (NE Spain) representing mesic and xeric conditions and encompassing wide ecological gradients. The data consisted of 7-year to 13-year long inventories of mushroom production. EW production was favoured by cold and wet climate conditions during the previous fall and winter, and during the current spring and summer. LW production was enhanced by warm and humid conditions from spring to early fall. Mushroom yield was improved by wet late-summer and fall conditions, mainly in the most xeric area. This study confirms the ample differences found in tree growth and fungal production along ecological and climatic gradients. Clear relationships between mycorrhizal fungal yields and tree growth were mostly observed in specific sites characterized by severe summer drought. Specifically, latewood production seems to be the tree-ring variable most tightly linked to mycorrhizal fungal yield in drought-prone areas.