Understanding Araucaria
Araucaria is a genus of evergreen coniferous trees in the family Araucariaceae. While today they are largely confined to the Southern Hemisphere, during the Jurassic and Cretaceous they were globally distributed. There are 20 extant species found in New Caledonia, eastern Australia (including Norfolk Island), New Guinea, Argentina, Brazil, Chile and Uruguay. This guide describes the genus and its significance in qualitative terms.
Araucaria in Brazil
One species in the genus, Araucaria angustifolia — commonly known as the Paraná pine — is native to southern and southeastern Brazil and northeastern Argentina. Its seeds, called pinhões in Portuguese, are eaten as food, particularly among the Kaingang people in Southern Brazil. The tree is also a familiar symbol in the region: in Curitiba, Brazil, residents rank the emblematic Araucaria tree alongside the city's Bus Rapid Transit system as a symbol of the city.
Description
Araucaria are mainly large trees with a massive erect stem, reaching a height of 5–80 metres (16–262 ft). The horizontal, spreading branches grow in whorls and are covered with leathery or needle-like leaves. In some species, the leaves are narrow, awl-shaped, and lanceolate, barely overlapping each other; in others, they are broad and flat, and overlap broadly.
The two South American species A. angustifolia and A. araucana are mostly dioecious, with male and female cones found on separate trees. The other species in the genus are monoecious. The female cones, on the top of the tree, are globose, and vary in size among species from 7 to 25 centimetres (3 to 10 in) in diameter. They contain 80–200 large edible seeds, similar to pine nuts, though larger. The male cones are smaller, 4–10 cm (1½–4 in) long, narrow to broad cylindrical, and 1.5–5 cm (½–2 in) broad.
Notable Species
The genus is familiar to many people as the genus of the distinctive Chilean pine or monkey-puzzle tree (Araucaria araucana). No distinct vernacular name exists for the genus. Many are called "pine", such as the "Norfolk pine" (Araucaria heterophylla) although they are only distantly related to true pines, in the genus Pinus. The genus contains four extant sections and two extinct sections, sometimes treated as separate genera:
- Section Araucaria: Includes A. angustifolia (Paraná pine) of southern and southeastern Brazil and northeastern Argentina, and A. araucana (monkey-puzzle or pehuén) of central Chile and western Argentina.
- Section Bunya: Contains only one living species, A. bidwillii (bunya-bunya) of Eastern Australia.
- Section Intermedia: Contains only one living species, A. hunsteinii (klinki) of New Guinea.
- Section Eutacta: The largest section, including A. columnaris (Cook pine), A. cunninghamii (Moreton Bay pine, hoop pine), A. heterophylla (Norfolk Island pine), and numerous species endemic to New Caledonia.
Distribution and Paleoecology
Members of Araucaria are found in Argentina, Brazil, New Caledonia, Norfolk Island, Australia, New Guinea, Chile and Papua (Indonesia). Many if not all current populations are relicts, and of restricted distribution. They are found in forest and maquis shrubland, with an affinity for exposed sites.
The earliest records of the genus date to the Middle Jurassic, represented by Araucaria mirabilis of Argentina, and Araucaria sphaerocarpa from England. Fossil records show that the genus also formerly occurred in the northern hemisphere until the end of the Cretaceous period. By far the greatest diversity exists in New Caledonia, likely due to a relatively recent adaptive radiation, as all New Caledonian species are more closely related to each other than they are to other Araucaria. Much of New Caledonia is composed of ultramafic rock with serpentine soils, with low levels of nutrients, but high levels of metals such as nickel. Consequently, its endemic Araucaria species are adapted to these conditions, and many species have been severely affected by nickel mining in New Caledonia and are now considered threatened or endangered.
Some evidence suggests that the long necks of sauropod dinosaurs may have evolved specifically to browse the foliage of tall trees, including those of Araucaria. An analysis of modern Araucaria leaves found that they have a high energy content but are slow fermenting, making their ancestors a likely attractive target. However, a diet consisting solely of Araucaria may not have provided dinosaurs with sufficient protein and was therefore unlikely.
Uses
Some of the species are relatively common in cultivation because of their distinctive, formal symmetrical growth habit. Several species are economically important for timber production.
- Food: The edible large seeds of A. araucana, A. angustifolia and A. bidwillii — also known as Araucaria nuts, and often called, although improperly, pine nuts — are eaten as food, particularly among the Mapuche people of Chile and southwest Argentina, the Kaingang people in Southern Brazil and among Indigenous Australians. In South America, Araucaria nuts or seeds are called piñas or piñones in Spanish and pinhões in Portuguese, like pine nuts in Europe.
- Pharmacological activity: Pharmacological reports on the genus Araucaria are anti-ulcer, antiviral, neuro-protective, anti-depressant and anti-coagulant.
Taxonomy and Naming
The genus is named after the Spanish exonym Araucano ("from Arauco") applied to the Mapuche of south-central Chile and south-west Argentina, whose territory incorporates natural stands of a species in this genus identified as A. araucana; the Mapuche people call it pewen, and consider it sacred. Some Mapuche living in the Andes name themselves Pewenche ("people of the pewen") as they traditionally harvested the seeds extensively for food.
Genetic studies indicate that the extant members of the genus can be subdivided into two large clades – the first consisting of the sections Araucaria, Bunya, and Intermedia; and the second of the strongly monophyletic section Eutacta. Sections Eutacta and Bunya are both the oldest taxa of the genus, with Eutacta possibly older.
Practical Tips for Visitors
- Look for the trees in southern Brazil: Araucaria angustifolia, the Paraná pine, is native to southern and southeastern Brazil and northeastern Argentina.
- Try the seeds: The large edible seeds, called pinhões in Portuguese, are eaten as food, particularly among the Kaingang people in Southern Brazil.
- Recognise the symbols: In Curitiba, Brazil, residents rank the emblematic Araucaria tree alongside the city's Bus Rapid Transit system as a symbol of the city.
- Know the family: Araucaria are conifers in the family Araucariaceae, only distantly related to true pines in the genus Pinus.
- Ask locally: For the best places to see Araucaria species in the wild, ask at local botanical gardens, parks, or nature reserves.