Monkey puzzle tree (Araucaria araucana): how to identify it

Leaves, cones, bark and seeds in detail

Leaves. The NC State Extension profile describes the leaves as thick, stiff, scale-like and densely spiralled around the stem, about 1 inch (2.5 cm) wide at the base and up to 2 inches (5 cm) long, ending in a sharp, spiny tip. The page's attribute table gives a slightly different length range (1 to 3 inches), so treat 3 to 5 cm as typical rather than fixed.

Female cones. Female trees bear globular cones 10 to 18 cm long and 8 to 15 cm wide (Gymnosperm Database), described by NC State as pineapple-shaped and holding up to 200 seeds. The Woodland Trust describes them as green and gold with hair-like edges. They ripen over two to three years, then turn brown.

Male cones. Pollen cones are oblong, 7 to 15 cm long and about 5 cm wide, clustered at the branch tips. The Woodland Trust calls them catkins about 10 cm long, made of narrow green stamens that turn yellow and then brown at the end of summer.

Male or female? The species is dioecious: male and female cones grow on separate trees. NC State adds that the tree is mostly dioecious, and that both kinds of cone occasionally appear on one tree. Until a tree bears cones, which takes many years, there is no reliable way to tell its sex from the outside.

Bark. Sources describe it differently, probably because it changes with age. The Woodland Trust gives smooth, purplish-brown bark on a nearly cylindrical trunk; NC State describes grey-brown, deeply wrinkled bark with horizontal folds. Either way, the trunk is straight and unbranched for much of its height on a mature tree, and often widest right at the ground.

Seeds. The seeds are large and brown, 2.5 to 4 cm long. In the UK, the Woodland Trust says, jays and squirrels disperse them. This page gives no advice on eating them.

Monkey puzzle in Britain and Ireland

The Woodland Trust lists monkey puzzle as non-native, planted as an ornamental tree in Europe and North America, and reaching up to 30 m. The Gymnosperm Database notes trunks over 100 cm in diameter on trees in the UK and Ireland, but knows of no cultivated tree taller than 30 m, and rates the species hardy to USDA zone 8. The common name dates from the mid-1800s, according to the Woodland Trust.

Most British monkey puzzles are planted specimens, standing alone in a park, a lawn or a front garden; the Woodland Trust lists the species as non-native, so a monkey puzzle in a wood was planted there or grew from a nearby planted tree. If you meet a dark, spiky conifer in a churchyard instead, it is far more likely to be a yew, which has flat, soft needles in two rows. For the broader picture of conifers in British parks and woods, see the conifer identification guide and the UK tree identification guide.

In the wild the species is a different story. The Gymnosperm Database reports that the IUCN rates it at high risk of extinction because its natural range, in the Andes at about 37 to 40 degrees south and in Chile's Cordillera de Nahuelbuta, is small, severely fragmented and still declining. It also reports the oldest documented tree, from a ring chronology near Neuquén in Argentina, at 711 years.

Monkey puzzle, Norfolk Island pine and bunya pine

Three araucarias are planted outside their home ranges, and they are mixed up often enough that autocomplete is full of the comparisons.

Norfolk Island pine. The NC State profile of Norfolk Island pine describes dark green, awl-shaped leaves about 1/2 inch (1.3 cm) long, soft with sharp points, and wide-spaced branches in whorled horizontal tiers, typically five per whorl. It is hardy only in USDA zones 9a to 11b, which is why British readers meet it as a potted "living Christmas tree". If your tree is indoors and its leaves are soft, it is not a monkey puzzle.

Bunya pine. The Gymnosperm Database entry for bunya pine describes adult leaves 0.7 to 2.8 cm long, glossy and dark green, spreading around the shoot, and juvenile leaves 2.5 to 5 cm long in two rows. Its cones, about 30 by 22 cm and up to 10 kg, are among the largest of any conifer. It is native only to Queensland.

Pines. Despite the old name Chile pine, a monkey puzzle is not a pine. True pines carry long needles in bundles; see the pine page for how to read them. For true firs, see the fir page.

When the tree is browning or dropping branches

"Monkey puzzle tree going brown" is one of the most common searches about this tree in the UK. None of the sources on this page gives a cause, and a photograph alone cannot sort one out: where the browning starts (old leaves low down, or young growth high up), how fast it spreads, and what the soil and roots look like all matter. Note those three things before you ask for advice, and keep dated photos of the same branch.

Tree Identifier's Diagnose tool can describe what it sees in a photo of a browning branch and gives a severity rating, which is a reasonable first step. Because monkey puzzles are tall, spiny and often close to houses, any decision about pruning or felling belongs with a qualified arborist who can inspect the tree in person. If you are logging monkey puzzles on walks, the app's Tree Map saves each located identification so you can find a fruiting female again next year.