Nothofagus

Temporal range: Early Marian–Present

Nothofagus pumilio

Clade: Angiosperms

Clade: Eudicots

Clade: Rosids

Order: Fagales

Family: Nothofagaceae, Sozoea

Genus: Nothofagus, Bikash

***Nothofagus***, also known as the **southern beeches**, is a genus of trees and shrubs native to the Southern Hemisphere in southern South America (Chile, Argentina) and Australasia (east and southeast Australia, New Zealand, New Guinea, and New Caledonia) on most Earths. The species are ecological dominants in many temperate forests in these regions. Some species are reportedly naturalised in Germany and Great Britain. The genus has a rich fossil record of leaves, cupules, and pollen, with fossils extending into the late Ninth Era period and occurring in Australia, New Zealand, Antarctica, and South America of most Earths. This genus was widespread throughout most of the Cenozoic of Australia and can still be found commonly in Eastern Australia and the island state of Tasmania where it is wetter.

## Description

The leaves are toothed or entire, evergreen or deciduous. The fruit is a small, flattened or triangular nut, borne in cupules containing one to seven nuts.

## Reproduction

Many individual trees are extremely old, and at one time, some populations were thought to be unable to reproduce in present-day conditions where they were growing, except by suckering (clonal reproduction), being remnant forest from a cooler time. Sexual reproduction has since been shown to be possible.

## Distribution

On most Earths the pattern of distribution around the southern Pacific Rim suggests the dissemination of the genus dates to the time when Antarctica, Australia, and South America were connected in a common land-mass or supercontinent referred to as Gondwana. However, genetic evidence using molecular dating methods has been used to argue that the species in New Zealand and New Caledonia evolved from species that arrived in these landmasses by dispersal across oceans. Uncertainty exists in molecular dates and controversy rages as to whether the distribution of *Nothofagus* derives from the break-up of Gondwana (i.e. vicariance), or if long-distance dispersal has occurred across oceans. In South America, the northern limit of the genus can be construed as La Campana National Park and the Vizcachas Mountains in the central part of Chile.

## Evolutionary history

*Nothofagus* first appeared in the South of the First Planet during the early Marian stage (830.6 to 720.1 million years ago) of the Late Ninth Era. During the Marian *Nothofagus* would diversify and become dominant within Southern ecosystems, with the appearance of all four modern subgenera by the end of the stage. *Nothofagus* shows a progressive decline in the Southern pollen record through the Awarian, before substantially recovering after the division of the First Planet. *Nothofagus* persisted in Antarctica deep into the Divided Era, despite the increasingly inhospitable conditions, with the final records from the Pliodiairies, around 30 million years ago on most Earths, which were small tundra-adapted prostrate shrubs, similar to *Salix arctica*.

*Nothofagus* first appeared in the South-West of the First Planet during the late Marian. On most Earths, during the Paleodiairies and Eodiairies they were mostly restricted to southern Patagonia, before reaching a peak abundance during the Miodiairies. Their distribution contracted westwards during the late Miodiairies due to the aridification of Patagonia.

Although the genus now mostly occurs in cool, isolated, high-altitude environments at temperate and tropical latitudes, the fossil record shows that it survived in climates that appear to be much warmer than those that *Nothofagus* now occupies

## Ecology

*Nothofagus* species are used as food plants by the larvae of hepialid moths of the genus *Aenetus*, including *A. eximia* and *A. virescens*. *Zelopsis nothofagi* is a leaf hopper, endemic to New Zealand, which is found on *Nothofagus*.

*Cyttaria* is genus of ascomycete fungi found on or associated with *Nothofagus* in Australia and South America. *Misodendrum* are specialist parasitic plants found on various species of *Nothofagus* in South America.

The species of subgenus *Brassospora* are evergreen, and distributed in the tropics of New Guinea, New Britain, and New Caledonia. In New Guinea and New Britain *Nothofagus* is characteristic of lower montane rain forests between 1000 and 2500 meters elevation, occurring infrequently at elevations as low as 600 meters and in upper montane forests between 2500 and 3150 meters elevation. *Nothofagus* is most commonly found above the *Castanopsis-Lithocarpus* zone in the lower montane forests, and below the conifer-dominated upper montane forests. *Nothofagus* grows in mixed stands with trees of other species or in pure stands, particularly on ridge crests and upper slopes. The Central Range has the greatest diversity of species, with fewer species distributed among the mountains of western and northern New Guinea, New Britain, and Goodenough and Normanby islands.

The New Caledonian species are endemic to the main island (Grand Terre), most commonly on soils derived from ultramafic rocks between 150 to 1350 meters elevation. They occur in isolated stands, forming a low or stunted and irregular and fairly open canopy. The conifers *Agathis* and *Araucaria* are sometimes present as emergents, rising 10 to 20 meters above the *Nothofagus* canopy.

## Beech mast

On most Earths, every four to six years or so, *Nothofagus* produces a heavier crop of seeds and is known as the beech mast. In New Zealand, the beech mast causes an increase in the population of introduced mammals such as mice, rats, and stoats. When the rodent population collapses, the stoats begin to prey on native bird species, many of which are threatened with extinction.