Agreed, "all" is an unfair word. Thanks. It's more accurate to say the majority of it is returned to the atmosphere. Less than 1% of burned fuel typically becomes organic carbon, but also not all of the biomass exposed will actually burn either. There's also trace amounts of other content and a lot of particulate matter (which one may or may not consider as carbon 'returned to the atmosphere' I suppose)
1% add up if we can do it worldwide on a regular basis. (likely yearly, but you need the proper forester for each forest)
For that <1% left as carbon, comes >75% released as carbon dioxide and carbon monoxide, which needs to be recaptured. Tree capture by itself is already too inefficient -- you need to cover roughly the entire area of new mexico with trees to account for just one year of America's emissions. If you're only sustainably capturing 1% of that capture, we're nowhere near the order of magnitude necessary to be impactful on a global scale.
Further, even if we didn't face the issue of running out of land, we don't appear to be able to actually plant trees fast enough and well enough (many of the "millions of trees" planting projects, especially in developing nations, have had tree survival rates of under 10%)
Forests help and are part of the strategy, but fundamentally not moving the needle.