Shrubs are woody plants that do not exceed 5 m (16 ft) in height. Above 5 m (16 ft) woody plants are largely considered trees. Many people divide shrubs into two categories, shrub (0.5 to 5 m [1.6 to 16 ft] tall) and dwarf-shrub (under 0.5 m [1.6 ft] tall). The UNESCO (1973) vegetation classification document, which is globally recognized and utilized in vegetation mapping, identifies shrubland and thicket as subdivisions of "scrub" or compositions of caespitose woody phanerophytes 0.5 – 5.0 m (1.6 to 16 ft) tall. Shrubland are then defined under scrub as "most of the individual shrubs not touching each other; often with a grass stratum". In shrubland systems, shrub cover must generally form more than 25% cover, and trees generally less than 25% cover. Shrub cover may be less than 25% where it exceeds tree, herb, and nonvascular cover, respectively, except where total vegetation is less than 10%, which is classified as barren lands. Thicket is defined under scrub as "individual shrubs interlocked". For the purposes of this website we classify ecotypes as scrubland if they have an apparent mix of both shrubland and thicket compositions.