Vegetation on Nisyros and the surrounding islets is mainly dictated by the area’s geological basement and the manmade conditions affecting the region. The island’s landscape is characterized by the absence of plains and flowing waters. Therefore locals were forced to use sloping ground as farmland to engage in farming – arboriculture in particular. This is why Nisyros, although devoid of ‘real’ forests, seems to be covered in trees up to the tops of its mountains. The following tree types have been cultivated since ancient times: olive tree (Olea europea ssp. europea), almond tree (Amygdalus communis), fig tree (Ficus carica), oak tree (Quercus macrolepis) and turpentine tree (Pistacia terebinthus). Now that farming has significantly diminished, most farmlands have been turned into brushwood fields.

Nevertheless, natural vegetation of the island – before human induced influences – must have been forest or shrub based, a view further reinforced by the existence of Quercus coccifera, Pistacia terebinthus and Quercus macrolepis species. The first species, commonly known as kermes oak, found as tree or tall bush, assembles a forest between Profitis Ilias and Nyfios mountans; it also appears at the Evangelistria site in shrub clusters. The two other species, in the extraordinary cases they are found away from cultivated land (Agios Ioannis-Kyra Panayia), are the remains of a once extended forest.

Limited areas of shrubbery are found at uncultivated locations in Nisyros, as well as locations that can retain a significant amount of moisture e.g. gorges.

Nevertheless the prevalent type of vegetation on the entire island complex is types of brushwood, with Cistus creticus, C. salviifolius, Sarcopoterium spinosum and Erica manipuliflora being the most representative types of brushwood.