Forest ecosystem soil is fragile, because the soil is very loose due to animals, vegetation, insects, mushrooms. A large, old forest only produces on the order

Forest ecosystem soil is fragile, because the soil is very loose due to animals, vegetation, insects, mushrooms. A large, old forest only produces on the order of a foot of topsoil in 50 years. It is possible to produce more artificially with rainwater mitigation and drainage paths that are engineered rather than left to chaos. As a side effect, growing in the Sahara would also potentially drastically reduce Atlantic hurricanes. So we have to decide what's more important, trees (move them to Sahara! Or at least replant equal numbers in Sahara and elsewhere) or human lives and infra.