How "good" are forest maps in the tropics?

• An extraordinarily intensive ground verification effort allowed us to create highly accurate (92%) pantropical forest maps and to better estimate accuracies of seven relevant alternative datasets. • The compared maps showed large areas of disagreement (from 17% to 24% of the total 15 million ha analyzed), mostly related to recurrent overestimations of forest cover by the global maps. • Errors increased in regions prone to host reforestation or restoration activities; there ground verification methods combined with the critical use of forest maps are especially pertinent.