The Magellanic subpolar forests are a terrestrial ecoregion of southernmost South America, covering parts of southern Chile and Argentina, and are part of the Neotropic ecozone. It is a temperate broadleaf and mixed forests ecoregion, and contains the World's southernmost forests.
The Magellanic subpolar forests ecoregion lies to the west of the Andes Mountains, which run north-south for most of their length but curve eastward near the southern tip of South America, terminating at the archipelago of Tierra del Fuego. The Magellanic ecoregion was covered by glaciers during the last ice age, and the landscape is deeply dissected by fjords, with numerous islands, inlets, and channels, including the Strait of Magellan, which separates Tierra del Fuego from the South American mainland and is the route taken by Portuguese explorer Ferdinand Magellan from the South Atlantic to the South Pacific. North of roughly 48° south latitude lies the Valdivian temperate rain forests ecoregion, which shares many affinities with the Magellanic ecoregion in plant and animal life. To the east lie the drier temperate grasslands and shrublands ecoregions of Patagonia, which are in the rain shadow of the Andean and Fuegian mountains.
The Andean and Fuegan mountains intercept moisture-laden westerly winds, creating temperate rain forest conditions, while the cold oceanic Humboldt Current, which runs up the west coast of South America, and the cold Antarctic Circumpolar Current, which runs from west to east through the Southern Ocean, keep the Magellanic ecoregion cool and wet, and the strong oceanic influence moderates seasonal temperature extremes. Averages temperatures a year vary from 6 °C (42 °F) in the north to 3 °C (37 °F) in the south and rainfalls a year from 4000 mm (160 in) in the west to 450 mm (18 in) in the east. Snowfalls can occur even in summer. Fog is very frequent. Very strong winds whip the region and these compel trees to grow in twisted and bent shapes fighting against the wind; and people call them "flag trees" .