Araucaria araucana

Araucaria araucana, commonly called the pewen, monkey-puzzle, pehuen or piñonero or Chile pine, is an evergreen tree belonging to the family Araucariaceae and growing to a height of and a trunk diameter of . Native to central and southern Chile and western Argentina, it is the hardiest species in the conifer genus Araucaria.

It is also the national tree of Chile and of the neighboring Argentine province of Neuquén. The IUCN changed its conservation status to Endangered in 2013, because logging, forest fires, and grazing have caused its population to dwindle. and so cover almost all of the tree, except for the older branches.

It is usually dioecious, with the male and female cones on separate trees, though occasional individuals bear cones of both sexes. The male (pollen) cones are oblong and cucumber-shaped, long at first, expanding to long by broad at pollen release. It is wind pollinated. The female (seed) cones, which mature in autumn about 18 months after pollination, are globose, large, diameter, and hold about 200 seeds. The cones disintegrate at maturity to release the long nut-like seeds.

The thick bark of Araucaria araucana, up to 15 cm thick, may be an adaptation to wildfire.

Taxonomy

The nearest extant relative is Araucaria angustifolia, a South American Araucaria from Brazil and northeastern Argentina, which differs in the narrower leaves and shorter bract spines on the seed cones. Members of other sections of the genus Araucaria occur in Pacific Islands and in Australia, and include Araucaria cunninghamii, Araucaria heterophylla, and Araucaria bidwillii.

Habitat

thumb|upright|left|Distribution map of A. araucana in central Chile

The tree's native habitat is the lower slopes of the Chilean and Argentine south-central Andes, approximately between and . In the Chilean Coast Range A. araucana can be found as far south as Villa Las Araucarias (latitude 38°30' S) at an altitude of Juvenile trees exhibit a broadly pyramidal or conical habit which naturally develops into the distinctive umbrella form of mature specimens as the tree ages. It prefers well-drained, slightly acidic, volcanic soil, but will tolerate almost any soil type provided it drains well. Seedlings are often not competitive enough to survive unless grown in a canopy gap or exposed isolated area. It is almost never found together with Chusquea culeou, Nothofagus dombeyi, and Nothofagus pumilio, because they typically outcompete A. araucana.

Seed dispersal

Araucaria araucana is a masting species, and rodents are important consumers and dispersers of its seeds. The long-haired grass mouse Abrothrix longipilis is the most important animal responsible for dispersing the seeds of A. araucana. This rodent buries seeds whole in locations favourable for seed germination, unlike other animals. and areas of national parks have also burned, destroying trees over 1300 years old. However, it is still unclear as to how large a role these invasive species play in threatening this species of tree. One study in particular found that native species played a larger role in preventing reproduction through seed destruction. However, this may be due to the relatively recent introduction of the selected species, causing their population to be smaller than other invasive species.

A study conducted found that cattle ranching by small landowners and larger timber companies within the range of A. araucana severely affects regeneration of seedlings.

Cultivation and uses

thumb|Monkeypuzzle tree at [[Salesforce Transit Center|Salesforce Park.]]

Araucaria araucana is a popular garden tree, planted for the unusual effect of its thick, "reptilian" branches with very symmetrical appearance. It prefers temperate oceanic climates with abundant rainfall, tolerating temperatures down to about . It is far and away the hardiest member of its genus, and can grow well in western and central Europe (north to the Faroe Islands and Smøla in western Norway), the west coast of North America (north to Baranof Island in Alaska), locally on the east coast as far north as Long Island, in the southern hemisphere south of its native range to southern Chile, and also in New Zealand and southeastern Australia. It is tolerant of coastal salt spray, but not air pollution.

Its seeds (, ) are edible, The tree has some potential to be a food crop in other areas in the future, thriving in climates with cool oceanic summers, e.g., western Scotland, where other nut crops do not grow well. A group of six female trees with one male for pollination could yield several thousand seeds per year. Since the cones drop, harvesting is easy. The tree, however, does not yield seeds until it is around 30–40 years old, which discourages investment in planting orchards (although yields at maturity can be immense); once established, individuals can achieve ages beyond Pest losses to rodents and feral pigs limits the yield for human consumption and forage fattening of livestock by A. araucana mast. The tree has a high degree of inter-year variability in mast volume, and this variation is synchronous within a given area. This evolved to take advantage of predator satiety. Timber from these trees was used for railway sleepers to access many industrial areas around the port of Chile. Before the tree became protected by law in 1990, some timber mills in Araucanía Region specialised in its wood because its durability and resistance to decay meant it was excellent for making wood products such as veneers and plywood.

The species is protected under Appendix I of the Convention on International Trade in Endangered Species (CITES) meaning international trade (including in parts and derivatives) is regulated by the CITES permitting system and commercial trade in wild sourced specimens is prohibited. Chris Page, a University of Exeter botanist working at Camborne School of Mines (CSM), planted specimens in disused china clay pits in the St Austell area as part of his research into regreening former extractive minerals sites, which he presented in 2017 in the UK Parliament, with Professor Hylke Glass, also of CSM, as co-author.

Araucaria araucana is locally naturalised in Great Britain, with e.g. many young self-sown trees at Kyloe Woods in Northumberland.

Etymology

First identified by Europeans in Chile in the 1780s, it was named Pinus araucana by J.I. Molina in 1782. In 1789, de Jussieu described a new genus called Araucaria based on the species, and in 1797, Pavón published a new description of the species which he called Araucaria imbricata (an illegitimate name, as it did not use Molina's older species epithet). Finally, in 1873, after several further redescriptions, Koch published the combination Araucaria araucana, validating Molina's species epithet in the genus.

The name araucana is derived from the native Araucanians who used the nuts (seeds) of the tree in Chile – a group of Araucanians living in the Andes, the Pehuenches, owe their name to their diet based on the harvesting of the A. araucaria seeds; hence from pewen or its Hispanic spelling pehuén which means Araucaria and che means people in Mapudungun. They believe the pewen was given by a deity or gwenachen to nourish their offspring; many pewen gathering festivals (ngillatun) are celebrated in both Chile and Argentina in gratitude to the tree's sustenance.

The origin of the popular English language name "monkey puzzle" lies in its early cultivation in Britain , when the species was still very rare in gardens and not widely known. Sir William Molesworth, the owner of a young specimen at Pencarrow garden near Bodmin, Cornwall, was showing it to a group of friends when one of them, the lawyer Charles Austin, remarked "It would puzzle a monkey to climb that". As the species had no existing popular name, first "monkey puzzler" then "monkey puzzle" stuck. As of 1996 Pencarrow had an avenue of mature monkey puzzles.

Gallery

File:Araucaria Madre.jpg|The 'Araucaria Madre' in Conguillío National Park, Chile; according to the sign, 50 m tall, 2.2 m trunk diameter, and 1,800 years old

File:Parque Nacional Conguillio - IX Región de la Araucania.jpg|The silhouette of the araucaria is very recognisable and has become a symbol for the southern regions of Argentina and Chile. Araucarias appear on the coats of arms of Neuquén Province and Araucanía Region.

File:Atravesando un bosque de pehuén (Araucaria arauca).jpg|Araucaria araucana in the Argentine Andes

File:Conguillio National Park.jpg|Bark of a tree in Conguillío National Park, Chile

File:Araucaria in Conguillio.JPG|Trees in snow in Conguillío National Park, Chile

File:Hojas de la especie arbórea Araucaria araucana, en Icalma, Región de La Araucanía, Chile.jpg|Leaves

File:Pehuen.JPG|Female (seed) cones

File:Araucaria araucana0.jpg|Male (pollen) cones

File:Monkey Puzzle Tree - Bergen, Norway - panoramio.jpg|Monkey-puzzle trees are popularly grown as ornamental trees; here, a young tree in Bergen, Norway

File:Piñones de araucaria cocinados.jpg|The seeds ('piñones') are similar to pine nuts, but larger; these roasted seeds are 3 cm and 5 cm long, from two different trees.

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References