The southernmost forest at Cape Horn

The southernmost forests of the world grow in the far south of Southern America, in the wind-swept Cape Horn archipelago. Just some 1.5 km from Cape Horn is a dense thicket of low shrubs and trees rising for a few meters above the peatland.

Magellanic subpolar forests

These southernmost forests belong to an unusual type of temperate rainforests – Magellanic subpolar forests. These forests are in the extreme southwest of South America, where the humid oceanic air brings abundant showers of rain. The climate there is cool – the medium temperature is just 3 – 4 degrees °C. Very frequent are storms and the very south – Hornos Island – is the stormiest among them all.

In spite of the low temperature, abundant rain is beneficial for vegetation. Low temperatures lead to another phenomenon – organic substances decompose slowly and, as a result, peat accumulates there faster than anywhere else in the world. As a result, it is even hard to tell the border between the ground and the “above the ground”: the forest grows on chaotic stacks of dead wood and leaves, legs of explorers all the time get stuck between the trunks and in the wet peat.

Description

Those tourists who manage to reach Hornos Island, usually see the southernmost forest when they visit the Faro de Cabo de Hornos and the nearby monument to the sailors who lost their lives at Cape Horn. But, in order to reach it, one should walk 4 – 5 km through the thicket. The weather usually is bad and, frankly, in the end, there would be not much to see anyway.Thus, only in January – February 2019, did a group of explorers explore this forest (1, 2). Their goal was not just to find the southernmost forest and trees but to collect data for future monitoring of climate change impact.

The southernmost forest of the world grows in a comparatively leeward location where the plants are protected by a mountain crest from the dominant western winds. It is exactly the force of the wind that prevents the further spread of forest on the island – the temperature and humidity there are suitable for forests.

The trees rise some 4 – 5 m above the ground. Constant winds have bent their trunks towards the east. In the forest grow several species of trees: ñire Nothofagus antarctica, Magellan’s beech (Nothofagus betuloides), and winter’s bark (Drimys winteri). One more common tree of Magellanic rainforests – Nothofagus pumilio – is absent there, although forests in the nearby Navarino Island have this tree as well.

The world’s southernmost tree is located just some 500 m south of this thicket. This is a low, small Magellan’s beach (Nothofagus betuloides) in a sparse group of seven trees. The tree rises above the ground for 57 cm, although it is some 2 m long. It is located just 17 m south of other tree species – ñire trees (Nothofagus antarctica) and winter’s barks (Drimys winteri).

Global climate change brings more severe winds to Cape Horn. Thus, the future brings more challenges to the hardy forest of Horno Island.

References

1. Brian Buma, Andrés Holz, Iván Diaz, Ricardo Rozzi, The world’s southernmost tree and the climate and windscapes of the southernmost forests, Ecography, September 2020. Accessed in 6 February 2022
2. Craig Welch, The tree at the bottom of the world—and the wind-blasted trek to find it, National Geographic, May 2021. Accessed in 6 February 2022

The southernmost forest at Cape Horn is included in the following article: