>You can't grow more iron ore

Steel is perfectly recyclable, but even then there is plenty of iron on earth. We won't be running out of iron.

Edit: Of course, steel is just a name of class of alloys - some of the steel types have a rarer elements like Mo, Ti, V...

Wood also requires heavy equipment to cut, mill, process. Not to mention, it needs a heck of a lot of land area. In addition to whatever process is involved in "hardening" this wood.

Plus, steel is entirely recyclable. And it has some natural properties that make is relatively easy to recycle. It can be sorted with magnets, and it has a higher melting point than most impurities.

The big advantage to wood though, is that while it's growing it's a carbon sink, and once hardened that carbon is likely stored forever.

you can achieve the same effect by making plastic with captured co2 [1]. Carbon would stay in plastic for very long time.

This way you get to reuse all the (enormous) existing infrastructure, as well.

[1] https://www.mdpi.com/2227-9717/9/5/759/pdf

Steel can be recycled/reused pretty easily. Just melt it down on an arc furnace and recast it. Can the same be said for hardened wood?

Indeed, steel is so recyclable that people will pay you for it regardless of condition. Contrast that to any kind of wood/pulp product.

> You can't grow more iron ore (though there is a lot of it lying around).

We live on a thin crusty shell around a ball of iron.

The ball of iron would be Earth's core, and between the thin crust on which we live and the iron core there is the very thick mantle.

Nevertheless, the mantle is made of a mixture of iron oxides, silicon dioxide and magnesium oxide, with small quantities of the other elements, so under the thin crust, even if there remain thousands of kilometers until the iron ball, there is nonetheless what is essentially a huge amount of iron ore.

> ball of iron

... which is way beyond our reach.

The iron in the universe is increasing over time.

On earth it replenishes too via meteorite strikes and by nuclear decay. I'm not sure was decays into iron, but I'm sure it's most things, given its name as the most stable element

Mind you, rust is quite similar to iron ore

Considering that the graphic references basswood, my guess is that the primary component of the final product, by mass, is not wood.