General Description

Nothofagus gunnii (N. gunnii) is a native small tree or large shrub from the Beech family and is only found in the Alpine and sub-Alpine, high rainfall forests of west and central Tasmania. It is Australia’s last surviving deciduous tree that sheds its leaves due to winter temperatures and has a fossil record that dates to 35 million years ago. Its showy petite vivid lime green leaves corrugated, and tooth like along the leaf margins create a unique and memorable plant. The IUCN Red List (2018) has deemed the plant to be Near Threatened

Landscape

N. gunnii is not common in urban landscapes, as it is notoriously difficult to cultivate and propagate ex situ. If it could be easily cultivated, with its elegant green distinctive crinkle cut leaves that turn golden yellow in the autumn the tree would make a wonderful specimen tree in small gardens or courtyards. Again, if it was possible to cultivate easily it would also make for mass plantings or small clusters of plantings as this is how it is found in its natural form. It would also lend itself well to poor soils that are low in nutrients, wet but well drained. The flowers and fruit seem small enough that they would not cause a litter issue and to date there are no documented pests or diseases which affect the plant.

Cultivation

The plant requires high rainfall, some frost, low snow lie, short periods of harsh exposure characteristic of Tasmanian winters, full exposure to sun and well-draining soil, that is low in nutrients. An exposed or protected site will correlate to whether the plant matures to a shrub or tree respectively.

Shape

The shrubs and trees grow in close clusters and appear as mass groupings.

Growth

Slow

ID Characteristic

The leaf would have to be one of the most distinctive features of this plant – those small crinkle cut leaves that are simple and ovate barely reaching over 1 cm in length and 2 cm in diameter. With a strong 3-dimensional wave that dips and rises again at each lateral vein that radiates from the midrib to the margin. The leaves seem to resemble corrugated iron that ends in little curved teeth along the edge of the leaf, which has a crenate margin. The next distinguishing feature would have to be those branches. Imagine the tree bronchioles of the human lungs and that is what will observed in winter as the branches are laid bare. As shrubs they weave and crisscross to create a tight tangle. As a tree it stands more upright and taller yet still retaining a multi stemmed vase appearance. It is endemic to Tasmania and is found nowhere else in the world. Finally, it is fascinating to think that this plant has not changed in over 35 million years and that its first home was the Supercontinent of Gondwana and that is the only surviving remnant of a time when winters in Australia were dark and cold and it made sense to shed leaves for the winter period.

Pests

Myrtle Wilt.

Habitat

It is restricted to high altitude regions between 800-1,200 m in the west to central portions of Tasmania.

Bark/Stem Description

The bark of the young plant starts as a smooth slender branch of a tan colour. The very young tips of the branches seem to have a very fine yellow down. As the tree matures the branches darken and begin to take on a patchiness, the smoothness gives way to a rougher surface. As the tree matures further the colouring changes to patches of light and dark grey. Specimens that are exposed rather than growing in protected areas, have bark that becomes muscular, with branches that are twisted and gnarled. The plant has thin bark that is susceptible to fire. In winter the bare twiggy branches resemble the human bronchial tree of the lungs making for a tangled dense form. Its intertwined branches which are rigid laterally but flexible vertically and its deciduous habit make it well suited for snow

Flower/Leaf Bud Description

Small narrowly conical buds with brown exterior leaves and lighter coloured leaves in the middle were observed from numerous photographs of N. gunnii. It was difficult to clearly observe the leaf scar, lenticel, vascular bundle trace and terminal bud scale scar from the photographs. No reference material was found on bud and stem morphology.

Leaf Description

The leaf is a simple ovate leaf with crenate margins (almost tooth like) and a very short petiole. The apex of the leaf is emarginate with the base of the leaf being rounded. The lamina of the leaf has a definite crinkle cut bulge to it, giving the leaf it’s undeniable uniqueness. A midrib starts from the base of the leaf up to the apex with deep grooves where the lateral veins radiate from the centre – pinnate venation. These veins seem to vary from 5 to 6 on either side of the midrib. The leaves are alternate and small, approximately 2 cm wide and 1 cm long.

Flower Description

Nothofagus gunnii is monoecious and has imperfect flowers. The male flowers are small, with a vibrant reddish calyx lobe extending and replacing petals, the yellowish filament and red 8 anthers spill out of the calyx to drop in a “pendula” manner, the stamens are numerous and look to be in gatherings of approximately 10 - 12. The flowers seem to be clustered singularly or in groups of 2. The female flower is again small and tinged a vibrant red in groups of 2 or singularly. The female flower is upright and looks like a tight bud that has opened slightly to expose the stigma tips that are held in a tight cluster in the middle. It seems that the pistils are protected by the involucre that makes up the exterior of the flower.

Fruit Description

According to Read N. gunnii fruits are 4 to 5 mm and the weight may correlate to its frequent occurrence on exposed sites. The dispersal unit is the fruit, a small two or three winged achene (nut). The fruits are borne in four-part cupules, each cupule containing 2 three-winged achenes, separated by 1 two-winged achene. The fruits mature with peak release in late summer and autumn. Although relatively light the wings of the fruit are poorly developed and not well suited to long distance dispersal. Hence why the trees cluster closely, and it takes considerable time for the trees to regenerate an area after a fire.

Colour Description

A growth flush occurs in November with the leaf turning a vibrant lime green and then turning golden yellow, and some orange or red in late April and May after which time the leaves fall. This golden yellow, orange, and vibrant red autumn colour creates a spectacular and welcome show in an otherwise sea of ever green plants that make up the Australian bush. This spectacular display attracts up to 3000 visitors in the course of just one weekend. In the summertime the lime green leaf is beautifully complemented with the red involucre encasing the achenia within whilst the male flower is a mixture of cream filaments and reddish calyx lobe and anthers.

Texture Description

Fine, but with time and exposure to the elements and high altitude the plant becomes more coarse in texture.

Notable Specimens

Mt Field National Park, Tasmania. Mt Olympus, Tasmania. Cradle Mountain, Tasmania. Lake St Clair, Tasmania. The Royal Tasmania Botanic Gardens has at least one specimen, but it is small, at only 50 cm in length.

Propagation

Seeds can be germinated under light or dark conditions with or without cold stratification and that laboratory trials suggest N. gunnii seeds germinate more quickly at low temperatures.

Ethnobotanical Uses (Disclaimer)

There seem to be no ethnobotanical uses for N. gunnii either in the past by The Aboriginal and Torres Strait Islander people or by early settlers, nor is there reference to the tree being used presently. This could be due to the natural characteristics of the plant: it is small, it grows in tangled stands, it is fine textured, the branches of the plant are intertwined, also as the plant ages in exposed sites the branches become twisted and gnarled making it difficult to harvest and not suitable for timber trade, lumber, wood industries or paper and pulp industry. There is also no mention of the plant as a traditional or modern day medicinal or food source.

Baldwin,H., Barstow, M. & Rivers. (2018). ICUN Red List Nothofagus gunnii, Tanglefoot. IUCN Red List of Threatened Species. https://www.iucnredlist.org/species/96478350/96479985 Veblen, T., Hill, R. & Read, J. (1996). The Ecology and Biogeography of Nothofagus Forests (pp.153-160). Yale University Press.