The drivers of tree cover expansion: global, temperate, and tropical zone analyses

This paper uses new, high resolution satellite-derived data to explore recent cross-national differences in expanding tree cover throughout the globe as well as in temperate and tropical nations. Increases in tree cover have concentrated in nations with recent histories of extensive deforestation, rugged topography, small numbers of farm workers, and declining rural populations. The spatial association of tree cover losses and tree cover gains suggests a kind of ‘forest churning’ in which owners engage in serial deforestation and reforestation. The concentration of expanded tree cover in countries with large montane regions suggests that a long-term pattern of regenerating upland forests and disappearing lowland forests is emerging both globally and in the tropics. This pattern is consistent with theories about forest transitions and would enable land sparing conservation strategies. Policy reforms to expedite these landscape changes, for example through REDD+ initiatives, would promote upland watershed conservation as well as biodiversity-rich montane forests and could have valuable redistributive effects for small farmers