Does planting trees really help cool the planet?

“The researchers acknowledge that the scenario modeled in the study is unlikely to be realized. It assumes trees could be restored to all areas where they once grew, which would require reclaiming developments such as housing as well as farmland and pastures.”

Restoring every forest to preindustrial extent would cut warming by 0.34°C. That needs about a trillion trees on land 135% the size of the US, including farmland and housing. Tree pledges are cheap. The math says they cannot replace cutting emissions.