A million dollars worth fungus

A million dollars worth fungus

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Photo courtesy: youthareawesome.com

For centuries the masterfully crafted Stradivarius violins have been enchanting the world of musicians with their distinctively finer sounds. The instruments, around 650 of them in the world, have been revered and passed on for generations or sold for millions of dollars.

But you might be asking what a Stradivarius violin, viola or cello might have to do with fungi? Let me explain.

In the quest to decipher what exactly made the renowned instruments so special, scientists have several theories. One modern hypothesis is implying that the wood which Stradivari used to make the instruments grew during a period of global cold temperature, the “Little Ice Age”. This period, cca between 1645 to 1750, called Mander Minimum, is associated with unusually low solar activity, thus cooler temperatures throughout Europe. This is thought to have stunted and slowed down tree growth, making the wood less dense and more elastic. The conclusions of their study was published in the journal called “Dendrochronologia”.

Commonly, the wood used to make instruments is treated with substances such as varnishes, primers or minerals to stiffen it. This process increases the density and the vibrating mass, which reduces the speed of sound and the resonance frequencies. Other chemical treatments increase the dynamic modulus of elasticity and decrease the damping factor, but in the end, because the crystallinity of the cell wall is increased, it is considered to be disadvantageous for the wood processing.

So, in order to manufacture instruments that could compete in quality with the reputed Stradivarius, scientists Francis Schwarze and Mark Schubert had an idea which involves the fungus, namely Physisporinus vitraeus. What they want to achieve is superior “mycowood” (wood with fungal treatment) that would provide manufacturers with materials for better-sounding yet cheaper instruments.

Physisporinus vitraeus is a basidiomycete (Polyporales, Meripilaceae) – It can be distinguished by its characteristic decay, a clearly visible white rot. The fungus forms on angiosperms, and seldom on gymnosperms. It can be found in North America, Puerto Rico, Europe and New Zeeland. In addition, studies have shown that isolates of Physisporinus vitraeus have the ability to induce significant permeability changes in the heartwood without losing impact bending strength.

For their study, Schwarze and Schubert chose wood specimens of Norway spruce and sycamore, studying them microscopically, mechanically and physically, before and after incubation.

Incubation of Norway spruce wood with Physisporinus vitraeus caused density loss and cell wall thinning; this means that the partly degraded wood resembled superior resonance wood grown under cold climate conditions. By assessing the specimens, the scientists found alterations in the wood structure which now had lower density and little change in the speed of sound. After 20 weeks incubation, the wood had reduced in density by more than 10% and it was noticed an increase in sound radiation, without any weakening of the structure.

In conclusion, the study proved that treating wood with fungus, making it into “mycowood”, improves considerably the quality of the wood and makes it usable for instruments resembling the Stradivarius ones. This technology is very important in a time when, because of the global warming, it is becoming increasingly difficult to find naturally grown, superior-quality resonance wood.

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A report by Ioana Popescu

 

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