As we all know, besides the origin and variety, the shelf life of wood is also an important factor in measuring material value. However, many people, including some masters and seniors, may have misunderstandings about the fundamental reason for shelf life. In the forum, I found that people usually say how many years the material has been air dried to show their attention to material quality. Of course, it is an undeniable fact that the longer the storage period, the more stable the material becomes. However, I would like to remind you that the storage period is not actually for drying wood. This is smaller than the moderator, who is a professional master after all. I remember he also mentioned the real reason in the video, but it was not clear enough.

get down to business. Imagine, if it were to dry wood, there are many drying technologies available now. If placed in a drying room, it can achieve several years of dryness in just a few days. I think Master Pang is very boastful about his wood moisture meter, and I think he is one of the typical qin making masters who have fallen into the trap. Haha~

 

So what is the purpose of placing wood for? The real purpose is to degrade hemicellulose. To clarify this issue, I have initially learned that there are three main components of wood: lignin, cellulose, and hemicellulose. Additionally, there are some resins. Many friends may classify hemicellulose into resin, but there is still a significant difference between the two.

Cellulose is arranged in an orderly manner in plant cells, serving as a skeleton and providing the tensile flexibility of wood. Hemicellulose is also the main cellular material that is interspersed and filled in the middle of cellulose in a discrete and non fixed form, providing support for living organisms. Lignin is the hard cell wall that constitutes plant cells, and in wood science, it seems to be a hard shell material, which means it must be relatively hard but relatively brittle.

Hemicellulose can be broken down into sugars, probably similar to starch. During times of famine, the main source of energy for eating tree roots and bark was hemicellulose, while lignin and cellulose were difficult to digest. Ha!

 

Then I finally figured out that the main contributors of wood as an engineering material should be lignin and cellulose, similar to steel reinforcement and cement. Cellulose is steel reinforcement and lignin is cement. Lignin is hard, while cellulose is flexible. For violin, both the elasticity of material vibration and the rigidity of the material acting on the air as a whole to produce sound are important!

 

However, hemicellulose is actually a highly hygroscopic substance. Once it absorbs moisture, it is difficult to breathe, and the biggest problem is that it is distributed between cellulose fibers. When wood is dried, it will randomly shrink and polymerize, causing uneven stress and easy deformation and cracking of the wood due to the presence of hemicellulose. This will help me understand why I see violin wood merchants' material warehouses usually stack wood in a very regular manner, relying on gravity and pressure to overcome deformation and cracking during the drying process.