For context, this would in theory allow about 1/3 historical cumulative emissions to be absorbed over a century or so. Which is a start, but nowhere near enough.
Also noteworthy: the bulk of forest-based carbon offsets have been fraudulent.
The paper is here
What you mean are not “old-growth forests” (article) but plantations, although they might be managed a bit differently than tree plantations today. They will fail at fostering ecosystem diversity and will not be particularly resilient. Dead material is vital for a living, thriving forest.
Since you imply that your idea has no alternatives: If we reduce consumption of animal products, we can drastically reduce the amount of farmland (as 70% of worldwide farmland is used to feed animals who in turn “waste” a lot of their feed, as they are not turning plant calories into animal calories 1:1). In many regions, this will allow growing forests or re-establishing swamps which will then be able to store CO2 again. Even farmland that is sustainably managed can store a lot of CO2, that just means allowing some nature on farms again and plowing a lot less.