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The austral forest can be seen as the counterpart of the taiga (boreal forest), but these two biomes are very different. For example, the taiga is mostly conifer-dominated, while the austral forest possesses a way more mixed tree association, often broadleaf-dominated. This makes the austral forest more biodiverse, richer in micro-habitats for small organisms. Oceanic currents also reduce extreme temperatures, making liveable for less frost-tolerant tree species.
Austral forests are not found in the internal areas of Antarctica, due to the harsh climate. Forest-limit starts from 0 to 200 meters of altitude (0-650 feet), depending on the latitude and the influence of the Big White, now fragmented into two portions. Closed canopy makes the austral forest less windy than any tundra across the peninsula, a sure advantage for lots of animals. Canopy height can change locally, but it's generally between 20-30 meters high (66-98 feet).
Proportionally, Ellsworth island is the most forested location in Antarctica (>70%) due to its flat and hilly landscape, with few mountainous points. Despite this, Weddel island is the most tree-biodiverse, since it possesses lots of microclimates, due to the variable latitude.
A dubious beech and bamboo fir forest.
A "cocktail" of trees and shrubs
A "cocktail" of trees and shrubs
The austral forest is an amazing set of austral trees and boreal trees, the last ones most probably being the descendant of several invasive species that were introduced in South America by humans, during the Holocene. Firs, pines and willow are surely an example of this.
Antarctic conifers comprise at least three genera, like the conical pine (Meridipinus sp.) the antarctic cypress (Neopilgerodendron antarcticus) and especially the bamboo fir (Rapidabies criogena), a fast-growing tree that can grow 50 cm/20 in per year.
On the other side, the most important broadleaf trees are the dubious beech (Ignothofagus sp.), which include both evergreen and deciduous species, and the needle willow (Sempersalix sp.), an important pioneer species. The last one is a bizarre group of willows that convergently evolved needled leaves like conifers, attaining a max height of 20 meters (66 feet) in the largest species. It is the dominant genera in fire-disturbed forests, occupying both tree and shrub niches. It's also highly palatable, being the most appreciated food for herbivorous birds together with the dubious beech.
Other less dominant tree species are the roseberry (Empetriphyllum sp. ) from the Ericaceae group, the poisonous apple (Bonusmalus sp.) from the Rosaceae group and the arboreal currant (Magniribes titanicus) of the Grossulariaceae group.
An important shrub genus of Antarctica is the red canelo (Winteridrimys sp.), a riparian shrub of the Winteraceae family. It's highly poisonous, making it inedible for most antarctic birds, except for some passerine genera and a lineage of terrestrial coots.
At the edge of Antarctica: the austral oak and the bluecherry forest
At the edge of Antarctica: the austral oak and the bluecherry forest
In the northernmost areas of Antarctica (Weddell island and some isolated locations of Polarica) the coastal austral forest is an intermediate between taiga and a cold temperate environment. With less frosty winters and warmer summers, these areas are perfect for the development of an extremely competitive forest association, the Macropruno caerulae-Austriquercetum. It's an extremely lush forest, dominated by two tree genera: the austral oak (Austriquercus sp.) and the bluecherry (Macroprunus sp.). Despite being pretty shady, the undergrowth is rich in sciaophile shrubs and herbs that can't be found in other tree associations. Macropruno caerulae-Austriquercetum possesses the highest canopy in Antarctica, locally reaching even 40 meters (131 feet).
If the antarctic climate will become hotter, this type of forest will surely expand its range elsewhere.
A winter view of a Macropruno caerulae-Austriquercetum forest association in Weddell island
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