A map illustrating temperate, subtropical, and tropical forests in monsoon Asia. A plot of temperature against photoperiod illustrates that seasonal variations in environmental signals decline towards the equator, and the diameter of the major axis of the photoperiod-temperature ellipse becomes shorter. A plot of precipitation against temperature in the tropical zone suggests precipitation can be a major driver of phenolog in tropics. The WorldClim database and National Astronomical Observatory in Japan were used to draw these two plots.