An overdue post, but you can find Dan's work on biases in global tree cover products here:
https://www.mdpi.com/1999-4907/10/10/853/htm
Dan's research, titled, "Identifying Biases in Global Tree Cover Products: A Case Study in Costa Rica" was published in Forests last fall. In short, global tree cover products can have slight to severe challenges in mapping tree cover in agricultural landscapes and along gradients of rainfall and topography. Any user of these products should read this paper--under- and overestimates ranged from 10% tree cover up to 80% tree cover.
https://www.mdpi.com/1999-4907/10/10/853/htm
Dan's research, titled, "Identifying Biases in Global Tree Cover Products: A Case Study in Costa Rica" was published in Forests last fall. In short, global tree cover products can have slight to severe challenges in mapping tree cover in agricultural landscapes and along gradients of rainfall and topography. Any user of these products should read this paper--under- and overestimates ranged from 10% tree cover up to 80% tree cover.