The studied Quercus robur trees were oaks protected as monuments of nature (200-350 years old) and oaks growing in forest stands (200-300 years old).The most visible symptoms occurring in aboveground organs included defoliation (25-75%), dying of twigs and branches.Discoloured heartwood, Clip Set obtained with an 80-cm Pressler borer, differed in colour intensity from normal wood and was divided into two groups: stained brown and dark brown.
The brown-stained heartwood was a more active site, Handbag considering the number of fungi and their ability to produce enzymes (phenoloxidase, pectinase and cellulase) in comparison with the dark-brown-stained heartwood.This brown-stained heartwood contained also statistically more Ca, Mg and Mn.