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From trees to lumber


The process of making wood products begins with converting trees into lumber.

 

Originally, we make products such as shoji screens and ceilings of Buddhist altars that require thin square lumber, manufactured from straight wood with few knots.

 

The lumber manufacturing process is actually a very time-consuming process.

 

Here, we will explain how trees are converted into lumber, and it can be roughly divided into three steps: Felling, lumbering, and drying.


◆ Felling

 

The first step is felling of trees. Although we do not perform this process, generally speaking suitable season for cutting tree is different depending on the type of tree, so that trees are harvested according to a plan. 

 

In particular, cedar trees are left for a while on the mountain in order to naturally remove sap and moisture, instead of transporting them immediately after cutting. This process is called Hagarashi in Japanese (literally means drying leaves), which not only improves quality, but also makes the wood lighter and reduces transportation costs.


◆ Lumbering

 

How do they cut logs and raw wood that are brought to a sawmill factory?

 

First, the bark is peeled off to check the condition inside and the log is measured to decide how to cut. In Japanese, this process is called “Kidori (lumber conversion)”. Each tree has a different length and shape. Some are straight, some are heavily bent, and some are even scratched. The cutting position should be determined by assessing the characteristics of each tree to obtain the best yield.

 

In most cases, a log is cut into large pieces first, and after drying, the bends are corrected and each piece is sawn further.

Trees are precious natural resources. We do not want to waste anything, so that the process is very important. However, in the lumber manufacturing process, some wastes are inevitable. If you cut lumber with a saw, sawdust will be generated, and some areas with scratches or knots may not be usable. Some designs incorporate scratches and knots in a creative manner, but unfortunately, they are not always usable to avoid making materials vulnerable or susceptible to corrosion.

 


◆ Drying

 

After lumbering is done, you might think that the lumber is ready to be used to create a product, but there is one more process to undergo.

 

The bucked materials still contain sap and moisture. After dried in the air, finally the lumber becomes ready for making products. In some sawmill factories, a kiln is used to dry wood.

At our company, sawn lumber pieces are piled up outdoors with a roof, and finished while being exposed to the wind. The reason for laying them horizontally is to make straight materials without warping. 


It takes at least two years to complete the lumber manufacturing process after harvesting trees in the mountains.

Finally, the lumber is ready and we can start creating products.

 

It's a really long way.


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