This is what I don't understand about companies planting trees to offset their fossil fuel CO2. Our problems are heavily caused by carbon being dug out of the ground and released. A tree just means that the carbon will be released at a later date
Bill Gates recommends a company for doing offsetting that actually pulls carbon out of the air and sequesters it underground, removing it from the carbon cycle: https://climeworks.com/subscriptions
It appears to cost ~$1/kg, but I'm guessing that will come down substantially if they're able to scale it up.
And by planting the right kind of trees, we could even go a long way to repair and safe our forests which are suffering from climate change and monocultures.
1. the tree will eventually be replaced by another tree, but more trees are being planted overall than are dying, so their numbers go up
2. the time dimension matters a lot. i.e. sequestering lots of CO2 inside trees now is still useful even if it gets released later because by then maybe technology will have improved to be less fossil fuel dependent.
Though, replacing the cover isn’t enough and more needs to be done - such as reducing greenhouse gas emission and removal of greenhouse gasses ( by using Carbon Capture Systems, for example).