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Comment by Maakuth | Hacker News Reader

Even when sawed into boards for construction, quite a big fraction of the mass is discarded during the process: the branches, the bark and the parts of the timber that is leftover geometrically in the sawmill. Then all the shaving, sanding, cutting, drilling, etc. and surprisingly small part of the growing tree ends up as a part of a building.

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But but all the leftovers are not necessarily burned down. Some of it is (that's where most pellets come from I believe), some is left in nature and becomes part of soil, some is reused in particle board.

I don't know about the carbon impact of what goes back in nature, some is decomposed by bacteria, some just stay there, some may act as a fertilizer, I don't think it is bad.

Exposed wood in the ground doesn't last long, if it does become part of the soil the carbon will escape into the atmosphere. The branches in cold climate might take a decade to decompose, but those too will end up releasing carbon quite soon. It is true that nature takes care of it, so it's not a waste problem like plastic is, but carbon-wise this part of wood stops storing not long after the tree is cut.

>Then all the shaving, sanding, cutting, drilling, etc. and surprisingly small part of the growing tree ends up as a part of a building.

It doesn't just get tossed in the trash, though. They do all kinds of things with the off-cut.

Some of it will end up getting burned, but even in that case it's displacing other forms of heat source, albeit less efficiently.

Hmm. I live in a forest. The people who come get logs for lumber mills only take the logs. All the branches, pine needles etc. are burned on-site. They'd never pay to haul that stuff (which is a massive amount of material) off site.

Why burned? In most tree plantations I visited branches were placed in piles for insects, small animals and shrooms to enjoy it. It then degrades over a year or two into some soup of carbon, nitrogen and potassium I guess.

I was under the impression a lot of larger sawmills were using leftovers in engineered wood products now. E.g. *DF and OSB

A lot of that is turned into engineered wood like OSB, LVL, etc.

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