Influence of understory vegetation on fungal communities and 2,4,6-trichloroanisole contamination in raw cork from standing trees

Cork oak forests are of considerable economic importance, they serve as pastures, and they produce the raw material used by the cork industry. In many instances, the economic value of cork oak forests is closely linked to the demand for cork stoppers used in winemaking, and any decline in cork quality can have significant undesirable consequences. This is particularly relevant for cork taint associated with off-flavours caused by 2,4,6-trichloroanisole (TCA) and formed by microbial methylation of 2,4,6-trichlorophenol (TCP), a precursor that can originate either from anthropogenic sources, such as pollution or pesticides, or from natural cork components. This study compared fungal communities and TCA contamination levels in cork from forests with and without shrub understory, selected to assess the potential influence of understory vegetation on fungal composition and TCA formation. The correlation analysis showed a highly significant relationship (p = 0.005) between understory presence and TCA levels, with a moderate positive correlation (r = 0.26), suggesting that while understory presence contributes only partially to this correlation, it may also influence consequent environmental variables that contribute to TCA variability. These findings suggest that forest management practices aimed at controlling understory vegetation are crucial for reducing cork taint contamination and enhancing cork quality. At the same time, maintaining fungal and plant diversity within cork oak stands requires management approaches that preserve ecological integrity while supporting the economic sustainability of cork production. • Understory vegetation is associated with higher TCA levels in raw cork. • Fungal communities are influenced by the presence of understory in cork oak forests. • TCA contamination may originate from fungi in living cork oak trees. • Understory control may improve raw cork quality.