This is constantly monitored and adapted. For example in Tanzania, they had 8 sites targeted for reforestation. 5 of them were healthy and growing with a high survival rate, but 3 of them ended up needing additional diversity to thrive.

They also don’t plant the trees themselves, but work with local groups such as women’s collectives, and partner with other organizations for the ongoing monitoring of survival and growth. 44moles (german company) is one partner I know of that provides ongoing monitoring, along with kanop.io.

The groups they work with are posted in their blog, which may have more information.

That said - monitoring is a more recent (past year or so) effort, so data is going to be limited. You’d need to wait longer for detailed information on survival rates.