Early detection of heartwood rot caused by Fistulina hepatica in Castanea sativa productive coppices through low-invasive resistance drilling

Chestnut Red Stain (CRS) is a heartwood discoloration that widely affects Castanea sativa Mill. productive coppice stands in the northeast of Spain. At the early stages of infection, the structural properties of the wood are not affected, but still its economic value drops up to 70% due to the rejection of this wood. This disease is caused by the fungus Fistulina hepatica (Schaeff.) With. and causes uncertainty to forest managers since the fungal infection is virtually impossible to detect before felling. The objective of this work was to develop an efficient detection method to evaluate the presence of F. hepatica in early stages of productive periods. A total of 72 chestnuts were analyzed through molecular methods to determine the presence of F. hepatica and with an IML resistance drill to characterize their wood. Thirteen wood quality indices were calculated and their correlation with the presence of the pathogen was evaluated using linear mixed models. We found clear differences between healthy and infected trees in four indices. A new specific index (Chestnut Red Stain Danger index) was designed to estimate the probability of infection by F. hepatica. The results support the hypothesis that the early presence of F. hepatica is detectable through inexpensive and fast mechanical methods early in a rotation. The results of this work will help forest managers evaluate the incidence of CRS, as well as it establishes a novel methodology for further development of resistance drilling techniques for heartwood rot detection.