Recently, several friends have been asking about what "raw material," "old material," and "aged material" mean. It seems that some of them, especially those who are new to this topic, still don’t fully understand the distinctions between these categories. In this article, I’ll explain these terms in detail and answer their questions.
Some of the content here is based on information from other authors. Due to time constraints, I can't list all sources individually. Thank you for your understanding!
Before diving into the three types of materials—raw, old, and aged—it might be helpful to first review the basic structure of wood. This will give a better foundation for understanding the terminology we'll discuss next.
The Bark, Sapwood, and Core Material of Wood
In the xylem (the woody part of a tree), the outermost layer near the bark is called the sapwood. It’s usually lighter in color and consists of living, functional cells. The core material, on the other hand, lies deeper within the tree and is darker in color. These cells have lost their vitality over time.
As shown below:
Raw Material
As the name suggests, raw material refers to freshly cut or living wood. Its main characteristics include the presence of bark (sometimes stripped) and sapwood—the white layer we often refer to as “the skin.†This type of material is typically moist, with high moisture content, and sometimes even retains leaves at the top.
We generally avoid using this kind of material because it's prone to warping and cracking during drying. Here’s an example:
This image comes from Baidu Pictures. As you can see, both the bark and the sapwood are clearly visible, which makes it a typical example of raw material.
Why Raw Material Cracks
Thuja wood contains polar hydroxyl groups, which cause expansion and contraction when moisture is absorbed or released. This uneven expansion and shrinkage can lead to instability in the wood, resulting in cracks and warping.
Related reading: Secret wood with English, numbers and other symbols
Chen Huan (Decayed Material)
Before discussing old materials, it’s important to first understand Chen Huan material. This term refers to Thuja wood that has been completely weathered and decayed on cliffs, leaving only the core material behind. Some people call it "weathered material," "de-agglomerated material," or "relic material."
As shown below:
Here, there is no bark or sapwood left. What remains is the gully-like structure that shows the passage of time. This kind of material is highly valued for its endurance and history.
Old Material
Now that we’ve covered the aging process, let’s talk about old material. By definition, old material refers to the stage after the Thuja tree has died on the cliff. It includes the period when the bark and sapwood are gradually weathering away. In other words, old material is the stage where the bark and sapwood haven’t fully decomposed yet.
Here’s an example:
The time span for this process is quite long. I remember a friend once told me that in the cliffs behind his house, there was a dead cypress tree. His father had seen it die when he was young, and now, in his forties, he found the same tree still standing—but the sapwood was still intact! This shows how slow the decay of sapwood can be, often taking decades or even longer.
Lighter supporting facilities, lighter air pump, air pump, water tower, fire-fighting facilities, lighter factory, lighter manufacturer, lighter manufacturer, lighter wholesaler, lighter craft, lighter manufacturing san'jianLighter supporting facilities, lighter air pump, air pump, water tower, fire-fighting facilities, lighter factory, lighter manufacturer, lighter manufacturer, lighter wholesaler, lighter craft, lighter manufacturing san'jian
Lighter Flame Adjusting Machine,Lighter Equipment,Llighter Production Equipment,Lighter Supporting Equipment,Lighter Machine
GuangDong Feituo Automation Technology Co., Ltd. , https://www.feetoolighter.com