Leaf Area Index is a satellite measurement of vegetation density and greenness. It is generally aimed to analyze forested areas where trees create a canopy over the ground (agricultural areas can also be detected during the growing season). LAI is the ratio of the one-sided green broadleaf area (or needleleaf area) per unit ground area. LAI significantly varies seasonally for deciduous trees, but varies little for coniferous forests as expected. Values typically range from zero (no vegetation) to 5-7 (very dense forest) leaf area index image