One of the visual modification of wood is the formation of dark zone lines (ZLs) via interaction of fungi. The result is called spalted wood, which has hitherto been produced mainly in small batches. The main goal of the present study is to further develop techniques for rapid formation of ZLs in hardwoods. Various white rot and brown rot fungi were tested to this purpose. Initially, interactions of 148 combinations of 17 basidiomycetes in malt extract agar were evaluated and their antagonistic interactions were characterised in order to identify fungal pairs capable of rapidly forming high-quality ZLs. Six types of interactions were observed, among others; antibiosis and inhibition in contact, which differ in terms of variables including mycelial overgrowth and zone line formation. Furthermore, 23 pairs of ZL forming fungi on malt extract agar were identified. Then the interactions of five selected pairs of fungi grown on the hardwood species Acer pseudoplatanus L., Betula pendula Roth. and Populus nigra L. were examined to assess their utility for controlled mycological wood modification, also in terms of a possible substrate dependency of their interactions. The results indicate that Lentinus tigrinus fungus is one of the best and quickest producer of ZLs in mycological wood modification.

To obtain special wood properties for various technical applications, fungi with their broad spectrum of activity can make a contribution. The foundations for today's mycological wood modifications were laid by researchers who wanted to increase the yield of edible mushrooms. They noticed the changed properties of the wooden substrate by the progressive wood degradation. Controlled use of fungi and an eye for the technical benefits of mycologically degraded wood revolutionized the fundaments of wood modification, primarily biological. In this context, the so-called Myko-Holz (myco-wood) plays a unique role and influences the current research for pencil wood, tone wood or even spalting.