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Comment by ZYinMD | Hacker News Reader

Could you please explain where will the wood eventually go? Wood (which contain all the CO2 they absorb over the years, if other readers haven't thought about it) have 3 possible destinies: #1 stay as live trees. #2 Die or get cut, then decay. #3 Get cut, made into timber, then used by human, e.g. furniture or construction.

#1 can't do much, because land is finite. #3 seems unlikely for your company, because it's hard to imagine inventing a new type of tree which happens to make more competitive wood than traditional trees, also because you didn't mention it. #2 seems your goal, because you did mention "slow decay", but slow decay is still decay, it doesn't matter whether a tree takes 25 years or 50 years to decay, all the CO2 it absorbs will eventually release back to atmosphere, which makes 0 net change. Could you elaborate on that? Thanks.

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Good questions! The end use of the wood depends on the location of the pilot project and how close it is to a mill. Given the duration of our pilot projects, the trees will be too large to be used for anything outside of saw timber for furniture of construction. We don't allow for our seedlings to be used for pulp / paper in our landowner agreements. Decay can also refer to the decay of wood products etc.

One of the biggest issues with forest carbon in general is the duration in which the CO2 can be stored before it is released back into the atmosphere. While trees have the benefit of being able to be planted right now at scale, climate change is a problem of relative rates. Currently, trees do lack the ability to store carbon for thousands of years underground. Of course you can coppice and keep replanting them post harvest but there will be some carbon returned to the atmosphere even if all your timber goes to wood products that have a long lifespan. Trees can't solve climate change on their own but they can quickly remove carbon in a low cost way buying ourselves more time to scale up other types of CDR solutions.

> #2 seems your goal, because you did mention "slow decay", but slow decay is still decay, it doesn't matter whether a tree takes 25 or 50 years to decay, all the CO2 it absorbs will eventually release back to atmosphere, which makes 0 net change. Could you elaborate on that? Thanks.

Not OP, generally skeptical, but will point out that delay is actually not a Bad Thing. It gives us time to consider what to do and look at other technologies that could make a more permanent dent in CO2 production/consumption cycles. Time is apparently a Big Deal for the fate of the planet and human race, and having a little more to see if there are other ways to mitigate damage seems good.

In the future carbon capture will be cheaper. By delaying the release of carbon after the maximum CO2 concentration it doesn't increase top temperature but instead just slows the recovery to the CO2 concentration our childrens children will decide they want.

Also temperature increase is roughly proportional to the integral of excess CO2 emission (actually more like a convolution with the life time curve of CO2 in the atmosphere) meaning delaying CO2 release means total peak excess energy will be lowered resulting in less worse ecosystem damage and maybe less feedback loops triggered.

Tying up the carbon for 25-50 years reduces CO2 levels now and thus immediate greenhouse impacts while allowing for energy production and industrial carbon sequestration methods to catch up. Think of it as a carbon mortgage, if you will, or the various peak-flattening mitigations at the start of the pandemic. We need more creative approaches like this to dampen the impact of climate change, especially while our energy is still dirty.

Remember that all those trees need to get planted and grow first. At best this will slow down the process, but not instantly shift it.

> #3 Get cut, made into timber, then used by human, e.g. furniture or construction

Option 3 is the best, especially for non-steel building construction, because it is real carbon capture into the frame of a habitable structure, of course barring a fire

If this would could be used for Cross Laminated Timber construction, that would be great. It can be used in mid to high rise buildings.

Don’t forget “burn up in forest fires”. I’m also curious if “decay” functionally implies a 100% carbon release rate or if some percentage is functionally sequestered.

If a tree is high in heavy metals and burns up, do the metals become airborne or are they heavy enough to remain in the ash?

Relevant: "Despite their destructive appearances even intense forest fires do not actually consumer much biomass. Only 0.1%–3.2%, since the larger trees and thicker branches that make up most of the biomass in a forest are good at resisting fires"[0]

[0]https://twitter.com/wrathofgnon/status/1503583221510184962?s...

You can also gasify woody biomass into syngas, which can be used for energy production. The gasification process can be optimized for biochar (carbon) production which can be introduced into the soil (terra preta) for nutrient absorption and carbon sequestration. It's estimated that biochar is inert in the soil for approximately 10,000 years. So reverse mining of carbon.

You seem to be suggesting extracting the hydrogen to use as fuel, leaving behind the carbon in solid form. Instead of just burying it, it might be more usefully made into fibers to mix into and strengthen concrete.

Yes, this is also an option, although biologically derived char-ash is more than just pure carbon, there are a number of other minerals (calcium, magnesium, silica) that would normally result in ash locked up with the carbon. It would not be impossible to remove these, in a separate step, either before or after gasification.

Note, pure hydrogen is not produced in Syngas, it is instead a combination of Hydrogen, Carbon Monoxide, Methane and other higher order burnable gases (if full pyrolysis and reduction is not completed). Not to mention inert gases such as Nitrogen, Argon, etc. if air is used during the partial combustion phase.

All that being said, the biochar that is left behind is super useful as an additive to soil, as it acts as a sponge for nutrients, a matrix for keeping beneficial bacteria alive, and often contains volatiles that stimulate plant growth (as it mimics the volatiles given off after a forest fire).

If they can get carbon credits and payment for cleaning up tox sites, #3 becomes more possible.

Well if it goes to buildings or paper, then to landfills, I think the carbon sequesters better? Is that correct?

Some of it must sequester, I'd guess most oil is actually dead plants.

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