AFAIK tree sequestration is marginal compared to the amount of co2 to be captured. Also, trees rot, and the decomposition process reverts a chunk of the process (releases co2)
Nope. Tree sequestration is extremely effective on a global scale. That's why it's so important that we prevent deforestation.
"Intact forests and those re-growing after disturbance (like harvesting or windthrow) sequestered around 4 billion tonnes of carbon per year over the measurement period — equivalent to almost 60% of emissions from fossil fuel burning and cement production combined."
http://theconversation.com/explainer-how-much-carbon-can-the...
In summary: its not as bad as I thought when I wrote the previous reply, sure. But it is still far from feasible.
I looked this up and seems it's the opposite. I'd politely suggest you check your assumptions are correct.
https://www.quora.com/Is-there-less-carbon-dioxide-at-higher...
https://667-per-cm.net/2015/08/04/atmospheric-concentration-...