Complexity of biodegradation patterns in spalted wood and its influence on the perception of US woodturners

Abstract

Figured woods (wood with frequent grain deviation) and spalted woods (wood with internal coloration from wood-decaying fungi, whether white rots, brown rots, or soft rots) are prevalent in both historic and modern woodworking. Both materials present a machining challenge, spalted wood in particular due to the decay caused by the inhabiting fungi. Despite the structural issues, the material remains in high demand in certain sections of the woodworking/woodturning communities. The exact reason for why woodworkers value spalted wood, and the methods through which they ascribe value to this material, is unknown. This research categorized types and amount of spalting on a given set of blocks and, through surveys, determined that the complexity of the spalted patterns (more visual indication of fungal colonization through more lines or color) was the driving force of the appeal. Increases in visual complexity significantly increased the value ascribed to the sample and the potential strength issues associated with spalted wood did not affect its value. Of the types of spalting surveyed, zone lines were found to be the most appealing, closely followed by pigmentation. Blue stains and white rots were not generally found to have value. The results from this study offer, for the first time, a window into how and why spalted wood is valued by woodworkers, and how this material, despite its many mechanical flaws, has stayed within the craft and art sphere.