Where will you put them? A recent study showed that just to offset _the yearly increase_ in CO2 emissions we would need to plant an entire continent of trees every year. And then ensure that they get adequate quantities of water.
Human CO2 emissions are so far off the scale of anything that has ever happened naturally that nature as she evolved on Earth has no way coping.
The best developed idea for CO2 disposal today is to compress to 1500 psi and inject into a saline aquifer. It isn't that hard to do, people have been doing injection into oil formations since the 1980s for "Enhanced Oil Recovery".
There are some questions about how long it stays there, induced seismicity, etc. but the way you're going to find out about this is by doing.
Human CO2 emissions are so far off the scale of anything that has ever happened naturally that nature as she evolved on Earth has no way coping.