In fighting climate change, few solutions are discussed more than planting lots and lots of trees. It sounds simple enough: trees absorb CO2 from the atmosphere, so planting more should help eliminate greenhouse gasses. The trouble is, tree planting efforts don’t always work as planned. So, when is it bad to plant trees? Carolyn Beans explores strategies to successfully re-green the planet. Lesson by Carolyn Beans, directed by Ivana Bošnjak, Thomas Johnson Volda.