Doesn’t a forest tie up the carbon in live trees? A mature forest will be more or less carbon neural but a certain amount of carbon won’t be available to the atmosphere.
If you want to get that out of the atmosphere, it's not good enough to grow trees today because in 50-100 years (or whenever a tree dies) you're right back where we are today.
[0] https://www.nationalgeographic.com/science/phenomena/2016/01...
You're right that we've added more carbon than can be stored in living forests. But reversing deforestation can & should be part of the solution.