Instead of scaling up like that, there are other ways that take advantage of positive feedback loops and decentralization — that is, a technology that can go “viral”.
There would not be a single source of failure. Such a system can be self -healing. It can potentially be adaptive if local people are able to implement it in ways that make sense for their place and community. (Otherwise, it runs into the same kind if globalist mindset from high modernity).
You don’t have to find a single tree species to do this. Instead, you look at what is already growing in the local area and plant those. Doing it that way solves way more problems than carbon emissions. We are talking about food forests (solve the food distribution problem), emotional and mental health (humans recover from illnesses better when they can see trees), resiliency (from decentralized food systems and biodiversity), and so on.
I mean you could in theory make a plant so good that it would outcompete almost any other plants. Then you might get a fungus or other disease that targets that monoculture and can now easily jump through the whole globe since it's covered in the same super plant. Being invasive is not a good feature.
