Carbonized wood (shou sugi ban)
A method that has been practiced and passed down for centuries yet rarely been discussed. It is something that has been used by Japanese fishermen to make their houses withstand harsh weather conditions, and seawater damages. This process is often compared to roasting. It is similar in a way as it requires high temperature, however, carbonizing is on another level.
Carbonizing to put simply, is changing the material to carbon removing moisture in each cell structure making the wood more resonant, lightweight with improved hardness. Doing so will change the properties of the material including its limitations and weakness. For musical instruments such as neck and fretboard, doing such will still require flexibility so determining the ideal spot between roasting and carbonizing plays the important role to make this work.
As a result, a more stable, durable material that display such dramatic grain with inordinate resonance.