Saturday, 21 March 2015

Monkey puzzle tree (Araucaria araucana)

The monkey puzzle tree is native to south-central Chile and south western Argentina but is cultivated in other areas of the world including the British Isles. Other names include monkey tail tree, Chile pine, pino araucana, araucaria, pino Chileno and pinonero. It is known as a living fossil and is a prehistoric tree dating back 210 million years ago to the Triassic period. It probably became extinct in the northern hemisphere around 65 million years ago.

An image of a mature monkey puzzle tree by Prashanthns - Wikimedia Commons
Mature tree by Prashanthns - Wikimedia Commons

The monkey puzzle tree is a slow growing long lived evergreen conifer with very sharp blade-like leaves. It will grow to around 30 metres in height with a spread of around 15 metres. There are twenty known species found around the world. It is often grown in the British Isles as an ornamental. However, it is now becoming popular as a food crop since it produces large edible nuts.

An image of young monkey puzzle trees growing in a pot in a polytunnel
Young monkey puzzle trees

This important tree is listed as endangered on the International Union for Conservation of Nature (IUCN) Red List Category - “Within the Andes and the Coastal Cordillera of Chile the population is severely fragmented and there is a continuing decline in its AOO due to a range of debilitating factors including fire, logging and overgrazing.” It is also listed on Appendix I of CITES which strictly regulates the trade in its timber and seeds.

Growing methods

A male and female tree are required to produce seed. Plant at least one male tree to seven female trees. There are male and female cones. Female cones are large, round and dark brown ranging from 12 to 20 cm in diameter. They develop in two to three years.They fall off of their own accord at maturity. When dried their split into three and produce 200 seeds. These are quite large at around 3cm long by 1 cm wide.

Monkey puzzle seeds. Left: with the leathery outer skin.  Top right: with the papery inner skin.  Bottom right: with all skins removed.
Left: the leathery outer skin.
Top right: the papery inner skin.
Bottom right: all skins removed.

The seeds have no dormancy and should be planted when freshly harvested. Plant them in pots or in the ground with the pointed end down. They will germinate at around 20 degrees C within two to four weeks. However, they may take longer and, unless the seeds have rotted, they may still germinate. Seeds will take longer to germinate at a lower temperature and they can be kept in the fridge to delay germination. Check seeds regularly and once a strong white root has emerged pot them on. Seeds that haven't germinated may be re-inserted back into the seed compost. When potting the seedlings on be careful not to break the root. It is best to use a stick or pencil to make a hole before inserting the root into new compost. Roots snap off quite easily.

Protect the growing seedling from harsh winter weather and plant out into their final position during the following spring or summer. They can be kept in pots for several years. However, all trees usually grow better the sooner they are planted into their final position. The monkey puzzle tree prefers well-drained slightly acid soil but will tolerate any type of soil. Producing heavy crops during cool summers, it grows well in the cool temperate climate of the British Isles.

Monkey puzzle seed with strong root growth

A. araucana is predominantly dioecious and its seed is gravity-dispersed or by birds and animals. It is pollinated by the wind. Asexual reproduction by root suckering has been reported (Schilling and Donoso 1976). Cuttings of half-ripe wood from May to July may be taken to propagate the tree. (Ken Fern, PFAF). However, only epicormic side-shoots should be used. These are shoots that develops from a dormant bud on the main trunk of the tree.

Where this tree does produce seed, it is high yielding. However, these trees are very SLOW GROWING(!) and may not produce seed until they are around 30 to 40 years old, although there are reports of trees producing seed at a much earlier age than this e.g. from 15 years onwards. There is no way of telling the sex of the tree until it flowers. Once the sex of the tree is known, it may be possible to produce female trees from cuttings.

The monkey puzzle tree will tolerate salty winds in coastal areas but not pollution.

Other uses

The resin of the tree is used to treat wounds and ulcers. The timber from the monkey puzzle tree is straight and of a good quality. However, it is now illegal to fell any trees from the wild. Its rarity and vulnerable status means the wood is rarely used now. Unlike most conifers, this tree can be coppiced.

Raw edible parts

The seeds are edible raw or cooked. They are large in size with a vaguely triangular shape and similar in appearance to a brazil nut. Fresh nuts taste a little like a uncooked chestnut or maybe a fresh green hazelnut. Ensure they are ripe before eating raw. Dried monkey puzzle nuts are more like a dried chestnut and are quite hard and dry. Dried nuts can be ground down to make a flour.

The seed is an important source of carbohydrates for the native people living in the south of Chile where it is eaten raw, boiled or toasted. The pinon seeds are composed of starch (64%), dietary fibre (25%), total sugar (7%) and very low concentrations of phenolic compounds, lipids, proteins and crude fibre.

Sources of seed for home growing

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