Earlier quoted context omitted.
A country of two million people managed to plant six million trees in one day in 2008 https://www.reuters.com/article/idUSTRE4AI49U/
Planting trees results in inferior forests. A healthy forest comes from natural forestation that goes through pioneer species stages.
You don’t have to take an empty field and plant 100k trees. You can go to where chestnuts used to grow, have some volunteers plant some over time, say 100 every month in an area. Over the course of 10 years, we’ll get some data.
Don’t let great be the enemy of good.