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Comment by thisisit | Hacker News Reader

"The production of cement, one of the main ingredients in concrete, generates an estimated 5 percent of the world’s carbon emissions. Trees, in contrast, capture CO2, helping offset emissions produced by a typical building process."

If I am reading this correctly it's the trees and not timber, laminated or otherwise, which capture CO2. So what kind of advantage does timber offer in form of CO2 emission? Specially considering the tree is now gone and this article doesn't cover if there is re-plantation - something like sow a 5 plants of each tree used for timber.

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Timber is carbon that a tree has pulled from the atmosphere.

As long as it stays in a building, it's not going back in the atmosphere.

Planting trees and turning them into timber is a form of carbon sequestration. As long as it doesn't burn or decay...

Also France forests are ones of the most well managed in the world. We consistently have more trees growing than being cut.

That's also true in the US. We have way more trees today than we did 100 years ago. https://www.mnn.com/earth-matters/wilderness-resources/stori...

It’s interesting, you could say that trees grow out of the air, not the ground.

Indeed, most of the mass of a tree comes from the air. Even the water was in the air not so long ago.

Yep, and when you (or any animal) lose weight, you're exhaling your body mass.

Richard Feynman on this very subject: https://www.youtube.com/watch?v=ifk6iuLQk28

The CO2 captured by the tree when it grows is captured in the biomass; the wood itself chemically contains carbon, which stays trapped until the wood is burned. (cf the carbon-neutral cycle of biofuels.) Basically an organic form of carbon sequestration that happens to produce useful building materials.

The issue of replanting is addressed at the end of the article, when they talk about sustainability - specifically in the context of having enough forest space that wood can be grown fast enough to keep up with demand.

> when they talk about sustainability

Problem is two-fold:

- Trees take quite a long time to grow

- Humans are notoriously bad at planning for the long term

What could go wrong? If the demands picks up the most likely outcome is an increased pace of deforestation.

> Humans are notoriously bad at planning for the long term

Quite the opposite in fact. Humans are better than any other living things on the planet at planning over extremely long durations in relation to their life expectancy. Few other living things can even plan beyond a very, very short duration to begin with.

We do 20, 50, 100 year business & government agreements.

We build power grids that last decades or a century. We also frequently plot out power supply / generation for our grids that extend over many decades.

We put up buildings that last centuries.

We create water systems that last centuries.

We implement government structures and programs that last decades or centuries by design.

We create places of education, such as universities, that last centuries.

We frequently plant renewable forests that require planning over decades.

We regularly choose careers and life pathways (eg marriage, children) meant to last decades.

When it comes to this planet, we're extraordinary at long-term planning, even though we're also obviously not perfect at it.

It's possible to be simultaneously bad at something and still the best. I think the idea that we're bad at planning comes partly from the fact that we fail to meet our expectations very regularly.

Still we have less and less rainforests. Maybe some of us are good in planning, but the questions is what's in focus. Money or sustainability. I think nowadays it is still money.

Can I disagree with some of your statements?

> We put up buildings that last centuries.

Not true anymore, Most modern constructions don't last very long. And this is survivorship bias as well, since most of what remains from previous centuries is just what was strong enough to withstand time. The large majority has disappeared and you just don't see it.

> We implement government structures and programs that last decades or centuries by design.

Look at the political map 100 years ago vs now, nothing lasts for very long. Look at currencies 100 years ago and now, you'd be surprised how much has changed as well. Political systems are by far the most unstable ones of your examples. You'd be lucky to be in a country for you whole lifetime without a drastic political or economic change.

> We frequently plant renewable forests that require planning over decades.

Yet we don't take care very well of ancient forests that were there for hundreds of millenia before us. Look what's happening in South America.

> We regularly choose careers and life pathways (eg marriage, children) meant to last decades.

The rate of divorces, single-parent families in modern times seems to indicate we are pretty bad at making such choices. They are "meant" to last decades but they usually don't.

> When it comes to this planet, we're extraordinary at long-term planning

We have also found ways to completely destroy and pollute our environment in a very short time, while the footprint of other species is much lower than humans overall. Overfishing has emptied fishes from many seas around the world. Numerous species are disappearing as we destroy their habitat. That's certainly not the signs of "species that plan well".

>> We regularly choose careers and life pathways (eg marriage, children) meant to last decades.

> The rate of divorces, single-parent families in modern times seems to indicate we are pretty bad at making such choices. They are "meant" to last decades but they usually don't.

This is mostly a "don't want to", not a "can't". Being married "only" once in your life (or having children...) is apparently considered boring, old-fashioned and backwards by many.

If there's a need, we're able to plan ahead. For example:

"On Visingsö you find Europe's largest oak tree forest. The oaks were planted here by the Swedish government in the 1830s to be used by the navy's ship builders. When the oaks were ready for harvesting in 1975 they were offered to the navy, which declined to buy them."

Excuse my poor translation, full article in Swedish here:

https://www.sydved.se/skogsagarliv/fran-vara-skogar/ekarna-s...

Industry consumes lumber like people breath air. Renewability of forests has been under serious consideration literally for centuries.

I think I read old rainforests and the like are actually carbon neutral because of this. Since the biomass is already at peak capacity, the carbon release from decomposition is equal to the carbon sequestration from growth.

As long as some of the old trees end up underwater in swamps each year they could bind CO2 for a few thousand years.

That said I agree that your basic argument sounds reasonable.

A lot longer than that. Coal is carbon from ancient trees.

Edit: I feel slightly stupid now.

That might often be a good sign I think :-)

IIRC that was before wood eating molds evolved. After that biomass hasn't accumulated long term so much anymore.

We are eating spoils.

Bogs can be wet enough so you can have airless conditions for moss that becomes peat and maybe ultimately can become coal under pressure but it's a really really slow process.

Coal deposits took a long time to be created, so it's hard to tell if they are still being created.

Are forests net sequestering 1/1,000,000 of an inch per year of carbon? That would produce a lot of coal over the next 300 million years. Remember, roots can go 100+ feet underground.

Opinions differ on that point. I'm familiar with the lignan/rot hypothesis. Another view is that major coal beds, including those of Appalachia and Europe, formed in subducting marshes at the margins of a rising mountain range. Fossil evidence of decay suggests lignan-persistence alone wasn't sufficient to explain accumulations.

I don't know which model is more likely, just sharing the info.

http://www.pnas.org/content/early/2016/01/13/1517943113

https://www.economist.com/news/science-and-technology/216887...

The lignin/rot delayed evolution hypothesis is just wrong.

There were molds that could digest lignin in that period. Furthermore, most of the plant mass didn't depend on lignin.

See http://phenomena.nationalgeographic.com/2016/04/06/getting-t...

That references the same PNAS article I'd posted FYI.

https://en.wikipedia.org/wiki/Tree_farm#Tree_farming_and_cli...

> Because tree farms are managed to enhance rapid growth, a tree farm tends to sequester carbon more quickly than an unmanaged forest, considering only the sequestration side of the equation and not the carbon release due to rot, fire, or harvest.[10] The fact that managed woodlands tend to be younger and younger trees grow faster and die less contributes to this distinction.[11]

> While tree farms absorb large amounts of CO2, the long-term sequestration of this carbon depends on what is done with the harvested materials. Forests continue to absorb atmospheric carbon for centuries if left undisturbed.

It’s also known that after cement sets, it begins to draw in significant amounts of CO2 from the air. I wonder if this was taken into account?

Most construction timber comes from plantation forests, where trees are replanted after harvest.

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