Also: These trees take decades to grow, at least, and will have to be protected from fires (which are only getting worse) and logging basically forever.
There is no “durable purpose” for lumber for practical purposes. Today’s construction lumber can last 100 years, maybe 200 years if someone really cares, but beyond that it’s simply not worth maintaining it if it’s not some kind of historic landmark. 100 years is long on human scale, but mere moment with regard to carbon sequestration.
At which point it can be buried in a landfill. That is, essentially, how all the coal be are burning formed in the first place.
At any rate, it still increases the buffer of sequestered carbon and still means these forests can be logged, as logging with replacement for construction would sequester multiple times the forest's mass in carbon even if the extra sequestration period was limited.
The best info I can find, trees soak up ~45 pounds (tops) of CO2 in a full year after it's about 10 years old in optimal conditions. Different trees, different amounts along with growing conditions. That's just optimal hopes and dreams after 10 years since germination.
