In woodworking, it's important to know about the structure of wood and the different types. If you've got the wrong wood, your project could fail or end up not being what you wanted. In relation to this, people often ask this question: why is heartwood darker than sapwood?
Trees trunk has different layers: the bark, phloem, cambium, and xylem. The xylem includes both the sapwood and heartwood. Before we answer the questions about, let's first define heartwood and sapwood. Then we will talk about the differences between the two and about how you can use them.
Sapwood vs. Heartwood
1. Location and Function
When you cut a tree down, you will notice that the rings of the tree have two distinct colors. The sapwood (or alburnum) is the outer and newer layer of the wood. It’s is essentially the living and working part of the wood because it transports water, nutrients, and minerals up to the leaves.
When new outer layers of sapwood grow, the older and inner ones “retire” and become heartwood. Even though heartwood (aka duramen) loses its transporting function, it still has another purpose.It is stronger than sapwood, thus providing the tree with structure and support.
You can identify heartwood as the darker and inner part of the wood, and sapwood as the outer and lighter part.
2. Appearance: Why is heartwood darker in color than sapwood?
When sapwood turns to heartwood, it stops from transporting water, sap, nutrients and minerals to the leaves of the tree. When this happens, organic matters start to fill up the cell walls and a chemical called extractives. This makes the heartwood darker in color. During the process, the heartwood becomes harder and stronger than sapwood.
Sapwood is also paler because it has high water content. It also lacks the dark staining chemicals that you can find in heartwood.
3. Workability: which do woodworkers prefer?
While high moisture is good for living trees, it is not ideal for woodworking. Wood high in moisture difficult to work with because it shrinks and it’s not stable. That’s why it’s better to have wood that has lower water content, and also why woodworkers prefer hardwood over sapwood.
Even then, woodworkers process their wood to make them stable. You can stabilize both hardwood and sapwood for them to be better to work with. Stabilizing will also make them stronger and more durable.
4. Durability: Which is stronger and more durable?
Heartwood in a living tree functions as structure and support. Since it is strong, it is more durable than sapwood. It also has higher resistance to fungus and other microorganisms, making it a better choice for furniture and other woodwork.
Tips when working with wood
- Take the necessary precautions when using sharp tools.
- Use protective gear such as gloves to have a better grip on your tools.
- Protective goggles can prevent small debris from getting into your eyes.
2. Stabilize wood
Stabilizing wood is a process where the wood is injected with resin to harden and stabilize the wood. You can stabilize any wood, as long as the moisture content isn’t high. The purpose is to make the wood more durable and easier to cut, shape, sand, and turn. A stable wood is also less prone to cracks and warping.
3. Get the right tools
The wrong tools can be counterproductive. For instance, using a dull tool can make your work take so long and you could even damage the quality of the wood. Get yourself off to a good start by using the right woodwork tools.
All wood starts as sapwood. They turn to heartwood when they lose their transporting function. As heartwood retires, it undergoes a process where organic matter fills the cell walls, which includes extractives that stain the heartwood.
It’s important to know a little bit about your wood before you do your woodwork. Otherwise, you might not get the outcome that you desire because your wood is the wrong type or part.
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