Globally, there was a net loss of 817,000 square kilometers (315,000 square miles) in forest area between 1960 and 2019, according to a new study. That’s nearly 10% more than the size of Borneo, the world’s third-largest island. The study showed that most forest loss occurred in “lower-income” countries as their economies grew, which are found primarily in the tropics. Forests in wealthier countries tended to expand. The authors say their findings confirm the forest transition theory, which links countries’ economic development to changes in land use. International organizations like the U.N. and rich countries should provide support to less-industrialized, forested countries to allow them to find economically beneficial alternatives to deforestation, the study authors say.