[agilvarry]

Personally, I use https://www.ecosia.org/(who would probably be a great company to try and partner with) as my web browser since they donate most of their profits to tree planting operations, and I give some money every month to Eden Project, who have been planting trees for a very long time and seem to have a good reputation.

If you're interested in helping out with their efforts it might be worth reaching out to trillion tree campaign. Their website really needs some work, but they've already done a lot of good work with some really big organizations. No need to re-do work when there is something already out there that you could potentially help expand on.