Cook Pine - Araucaria columnaris

The Cook pine (species: Araucaria columnaris) is a tree native to the Cook Islands (north-east of Australia in the South Pacific). It is often confused with its close cousin the Norfolk Island Pine (Araucaria heterophylla). If you have come across either of these tree species I hope that this post will help you to distinguish between the two. The first distinctive of the Cook pine is its tendency to has a slight "S" curve in its trunk. It almost never grows perfectly straight despite the name "columnaris". In very tall specimens in is pretty straight but even then you should be able to see some curvature close to the base of the tree. The Norfolk Pine on the other hand has a very straight trunk.

The second distinctive of the Cook pine is its flaky bark. Unlike the Norfolk pine the bark of the Cook peels off in thin paper like sheets like in the image above. If the curvature in the trunk does not solve the puzzle the flaky bark is a dead giveaway. I´m not sure if on the older more mature specimens this flakiness is less pronounced or not.

The third distinctive is the large flower like pollen cones that grow on the ends of the leaf-branchlets near the top of the tree in late spring. It is a lot less common to see this trait and on some trees these "flowers" are less pronounced than those in the image above.

The leaves of the Cook pine are for all practical purposes identical to those of the Norfolk pine. The branches though do give a clue. One the Cook pine the "layers" of branches tend to grow closer together making the younger specimens look more filled out with a christmas tree sort of look. The Norfolks on the other hand tend to have much more space between the layers of branches. Also the branches of the Cook tend to droop down more than those of the Norfolk. In addition the branches of the Cook tend to break off closer to the main trunk and then grow secondary branches giving the taller Cooks are thinner more column like apprearance.
This tree is also sold as a houseplant although it is often confused with the Norfolk and labeled as a Norfolk. The two species are very diffecult to tell apart when they are as small as the tree in the image below. On both the Cook and the Norfolk the juvinile leaves have a markedly different look than the leaves on more mature trees.

If you do have one of these as a houseplant keep in mind that it has a very low tolerance for freezing temps.