Klein T Randin C Körner C 2015 The tendency of trees to grow taller with increasing water availability is common knowledge. Yet a robust, universal relationship between the spatial distribution of water availability and forest canopy height (H) is lacking. Here, we created a global water availability map by calculating an annual budget as the difference between precipitation (P) and potential evapotranspiration (PET) at a 1-km spatial resolution, and in turn correlated it with a global H map of the same resolution. Across forested areas over the globe, Hmean increased with P-PET, roughly: Hmean (m) = 19.3 + 0.077*(P-PET). Maximum forest canopy height also increased gradually from ~ 5 to ~ 50 m, saturating at ~ 45 m for P-PET > 500 mm. Forests were far from their maximum height potential in cold, boreal regions and in disturbed areas. The strong association between forest height and P-PET provides a useful tool when studying future forest dynamics under climate change, and in quantifying anthropogenic forest disturbance. https://sonar.ch/global/documents/238158 eng info:eu-repo/semantics/altIdentifier/doi/10.1111/ele.12525 info:eu-repo/semantics/altIdentifier/pmid/26423470 Ecology letters. - 2015 Evapotranspiration forest suppression hydraulic constraints range limits tree height Forests Models, Biological Temperature Trees Water Cycle Water availability predicts forest canopy height at the global scale. http://purl.org/coar/resource_type/c_6501