Planting trees for climate services – storing carbon, cooling surface climate, enhancing rainfall, providing aerosols that reflect solar radiation, creating favorable microclimate refuges, or other benefits – is not small-scale or immediate. It requires vast tracts of healthy and thriving forests and setting aside the land to grow forests for 50 to 100 years or longer. Achieving the climate benefits of forests requires a permanent forest presence over many decades. Climate will change during that time, and a forest planted today may not thrive in the climate of tomorrow. The forests of the future will grow in a climate different from today's and likely in regions of the world that differ from today's. They will be stressed by climate change, increased wildfires, disease, and insects. Asking forests to solve the climate problem requires a long-term commitment to and investment in forests and their health. Forest growth, too, is not one-directional. Wildfires, droughts, insects, and wind storms continually reset forests back to young stages of development. An old-growth forest that has accumulated enormous stores of carbon in its trees and soil becomes a young, regenerating forest.