In the Garden: Dinosaur Food

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The author with a Monkey Puzzle Tree. Photo courtesy Charles Kidder.

If you’ve looked at museum dioramas or computer-generated images of dinosaurs roaming through a prehistoric landscape, you might have noticed tall gaunt pine trees in the background. This potential dinosaur dinner, the genus Araucaria, was widely distributed and reached its maximum diversity some 200 million to 60 million years ago; today it’s restricted to isolated populations in the Southern Hemisphere. Some herbivorous dinosaurs were the largest of their group, and scientists posit that they evolved longer necks to browse the foliage of the Araucarias. While dinosaurs are now gone, 19 species of Araucaria hang on, with the majority of those endemic to the island of New Caledonia east of Australia.  Despite common names like Chilean Pine or Moreton Bay Pine, they’re only distantly related to the true pines.

Perhaps best known to us is the Norfolk Island Pine, Araucaria heterophylla. Native to a tiny subtropical island of the same name a thousand miles east of Australia, we encounter it as a houseplant, often hung with decorations at Christmas; it’s also seen in gardens in warmer climates, where it can grow to 170 feet in height. The similar Cook Pine, A. columnaris, is widely planted in the tropics, and it’s likely you’ve seen it when visiting South Florida or Hawaii. It closely resembles the Norfolk Island Pine, but has denser branching and a very tight, columnar habit. This “Christmas Tree” shape, more akin to the spruces and firs of northerly latitudes, may look a bit out of place in the tropics, where we are used to seeing tall graceful palms or wide-spreading trees such as banyans.

The bunya-bunya, A. bidwillii, hails from Queensland, Australia and is planted in both the tropics and warm temperate climates; its most distinguishing feature is its huge cones. Over a foot in diameter and weighing more than ten pounds, for safety reasons botanical gardens cordon off the areas underneath these trees when they are dropping their cones. Imagine something bigger than a pineapple dropping on your head from eighty feet.

Among a clan of strange plants, the Monkey Puzzle tree (A. araucana) may be the most bizarre.  Young plants have an open, pyramidal shape of preternatural symmetry—I’ve seen artificial Christmas trees that look more realistic. The branches, covered with “leaves” that are more like daggers or box-cutter blades, droop downward, then arch upward at the tip. Mature trees lose the pyramidal shape and drop most of their lower branches; the flat top of foliage on a bare trunk gives an umbrella effect. With their penchant for the unusual, Victorian collectors took a shine to Monkey Puzzles. When one British gent was showing his new acquisition to friends, one commented that, “It would puzzle a monkey to climb that!” These trees don’t actually have to contend with monkeys in the wild, although some believe that their extreme spininess may have been a defense against long-necked sauropod dinosaurs. Luckily for indigenous peoples of South America, they don’t have to climb the trees to harvest seeds. The cones drop and reveal large “pine nuts” that can comprise up to 15 percent of the peoples’ diets during harvest time. The large quantity of nuts from a mature tree could offer some potential as a crop, if it were not for the fact that a Monkey Puzzle requires thirty to forty years to mature.

Indigenous to a small stretch of the Chilean and Argentine Andes, Monkey Puzzles are also widely planted in cool temperate climates. You’re likely to find them in the Pacific Northwest, the U.K. and milder areas of Continental Europe. But what about growing them in the eastern United States? For us, cold should not be the issue, since Monkey Puzzles live in an area with cold, snowy winters; the real problem may be summer heat and humidity, along with poor drainage in clay soils. You might expect more success in sandy soils, and in a phone conversation with Marie Butler at the Virginia Zoo in Norfolk a few years ago, I learned that they did have a 25-foot specimen at that time. A Monkey Puzzle tree is also listed as part of the collection on the Norfolk Botanical Garden website, and one reportedly grows at the Barnes Arboretum near Philadelphia.

Another possibility for growing an araucaria in our climate lies in a cross between the Monkey Puzzle and its close relative, the Parana Pine (A. angustifolia). The latter tree hails from Southern Brazil and adjacent parts of Argentina and Paraguay, an area with warmer and wetter summers that are more akin to ours. I’ve seen one example of this hybrid growing at the J.C. Raulston Arboretum in Raleigh; planted in 2012 as a small tree, it’s now eighteen feet tall. For the adventurous gardener, Plant Delights Nursery near Raleigh offers it for sale.

Araucarias’ tall straight trunks were useful for masts and lumber, even while nut harvesting limited reproduction, so many species’ natural ranges have been considerably reduced in recent times.  Indeed, some are now classified as endangered and receive protection in national parks. Consider yourself fortunate if you’re able to view any of the Araucarias in the wild, as you’re a witness to plants descended from the forests that dinosaurs once roamed.

This article is a revision of one that originally appeared in the Crozet Gazette six years ago.

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