https://natural-resources.canada.ca/stories/simply-science/e...

Interesting. I would have guessed that any kind of forests have quite limited cap how much carbon it could retain in dead wood, and that this cap will be pretty much fixed. Unless something will stop natural decay processes releasing the carbon back to the atmosphere I don't see how existing grown forest could increase its capacity, since I suppose it is already at its equilibrium.

(Unlike peatlands, where most of accumulated carbon remains underwater, so it presumably has much larger capacity.)

Simply said, without "burying or sinking wood mass" I see no easy way to prevent carbon from returning into the atmosphere. Basically if we need to take carbon from the atmosphere, we should ideally put it back from where we have been mining it for last couple of centuries.

efficiency of photovoltaic - 20%

so photovoltaic is 15 times more land efficient then burning biomass. so we absolutely need trees to provide ecological functions. but in era of 5kwp PV array paying itself in 5-6 years(and still working afterwards), to heat water... its is ridiculous to cut trees and burn them to have hot water. 80% of time Canadian citizen can have 100% solar hot water (PV), less then 100% rest of the year.

Get some fast growing plant like Japanese Knotweed or bamboo, grow it out for a year, harvest and dump the biomass into a decomissioned mineshaft to minimize contact with the atmosphere. Rinse and repeat.

One way humans can improve on this is by making charcoal out of wood and burying it or just spreading it on soil. This drastically improves the fertility of the soil improving the rate that that soil can sequester carbon by growing trees even faster, and, as long as the charcoal is mixed in soil and not in a huge dry pile on top where it might burn, this process need never reach an equilibrium and can keep accumulating more and more carbon, more and more fertility and water retention capacity, more and more abundance of food production. This is what the ancients did in making terra preta in South America and similar charcoal-infused soils that have been found all over the world.

We do this where I live in California. It's a way to reduce forest fuel load while increasing carbon sequestration and fertility. Only cost is labor. It's theoretically possible to do at large scale with machinery instead of people, though the attempts I've seen have not proved viable. For a low expense human-scale way to do it, just making big piles and burning them from the top down (so no smoke) - piling more and more fuel on as it burns, and then dousing with water once it's mostly a big pile of coals, works quite well. With the addition of a big metal ring for a kiln, efficiency can go up even more from (very roughly) 50% of carbon turned to charcoal, to maybe 80 or 90%. Numbers vary considerably. But in all cases, the amount of carbon moved from the rotting or burning cycle to permanently sequestered is significant.

Compared to the short term carbon sequestration of building things out of wood (99% of which will burn within a few centuries), these soils have lasted thousands of years. There must be some mechanism that will eventually recycle this carbon back to the atmosphere but it may be on the timescale of hundreds of thousands of years for most of it.

Forests will store carbon as and while they are growing, but as and when they reach a stable size they will stop storing additional carbon. That is, carbon stored by growth will equal that released by decay.

Otherwise plants/trees are just a type of carbon battery - pull carbon, burn for fuel, carbon goes back out, gets pulled back in again.

If that fraction isn't negligible, we'd be better off burning it. Determining that fraction, across a range of conditions, is nontrivial.

There's a bit of nuance to be filled out, like challenges of forest plantation monoculture and so on, but it always sounded quite practical to me. Iirc the idea derived from "coal".