Understanding the global patterns of forest canopy height and their underlying factors is a major task in ecology because forest canopy height is critical for aboveground biomass, species diversity, and several other ecosystem functions. While many local studies have demonstrated that hydraulic limitation, mechanical stability against the wind, and soil properties are major factors that limit tree heights, to our knowledge no study analyzes the global patterns of canopy height with considerations of these three major factors together. In addition, it is known that forest heights in tropical rainforests differ among the continents, i.e. Asian tropical rainforests are higher than American or African tropical rainforests, but its reason remains unclear. El Niño–Southern Oscillation (ENSO) brings occasional strong drought to tropical rainforest regions, therefore the aperiodic extreme drought may have an additional power to explain the variation of canopy height in tropical rainforest regions. We analyzed the global canopy height with considerations of these issues. We will report and discuss the importance of wind speed, soil properties, aperiodic extreme drought as well as several other environmental variables on the global patterns of forest canopy height.