“breathing in carbon dioxide and breathing out oxygen” – that’s the first advantage when we think of trees.

Many of us, including me, will think there are millions of cells and holes inside the branches, which enables the wood can release oxygen and absorb water.

So I believe that many people would think wood is porous since trees need to inhale and exhale.

Is that true? Let’s give it a closer look.

Is wood porous?

Yes and no. The answer may sound surprising to some people, but the truth is some woods are porous and some woods are not.

You may be wondering: “how come is wood non-porous? Are you talking about fake wood?”, you will be explained in a minute.

First, let’s take a look at the definition of porosity:

So what is porosity exactly?

When we say something is porous, normally we are saying that it can be penetrated by water or air.

That is to say, if water or air can pass through the object, we will consider it as porous. Or else, it’s non-porous.

In most of the cases, wood is porous because trees have pores to get moist and air.

But some woods with dense quality are semi-porous (You can see them in the next part), that’s why density is also the key that wood can float on water.

The less dense the wood is, the more porous it is. So some woods seem non-porous because they are too dense.

What’s more, with a special finish on the surface, wood can also be non-porous from porous.

Now we have our conclusion:

If you are seeking the answer to “is wood porous”, we can say that wood usually is porous, but not 100%.

What Wood is Non-porous?

We’ve mentioned that dense wood can be semi-porous or even non-porous to some degree, but no wood can be 100% non-porous. Otherwise, it can not be alive.

If we are saying the wood is non-porous, we probably say that it is dense and doesn’t have many pores and vessels in its wood fibres so that water and air will not soak through it quickly.

So normally dense woods like ebony and ironwood are less porous than others.

But we do have methods to make wood non-porous.

For example, with a special finish or process, like varnishes or lacquers.

The wood can be completely sealed and there is no way water and air will pass through its body.