A tree planted for every T-shirt purchased. For every bottle of wine. For every swipe of a credit card. Trees planted by countries to meet global pledges and by companies to bolster their sustainability records.

As the climate crisis deepens, businesses and consumers are joining nonprofit groups and governments in a global tree planting boom. Last year saw billions of trees planted in scores of countries around the world. These efforts can be a triple win, providing livelihoods, absorbing and locking away planet-warming carbon dioxide, and improving the health of ecosystems.

But when done poorly, the projects can worsen the very problems they were meant to solve. Planting the wrong trees in the wrong place can actually reduce biodiversity, speeding extinctions and making ecosystems far less resilient.