The Cook pine, Araucaria columnaris, leans toward the equator. In 2017 botanist Matt Ritter of California Polytechnic State University noticed that pines growing in California and Hawaii leaned south; he called a colleague in Australia, who reported that the trees there leaned north.

“We got holy-smoked that there’s possibly a tree that’s leaning toward the equator wherever it grows,” Ritter told Nature.

In both hemispheres, the trees lean more sharply the farther they are from the equator. The average incline is 8 degrees, but one tree in South Australia leans 40 degrees.

The reason isn’t clear; it “may be related to an adaptive tropic response to the incidence angles of annual sunlight, gravity, magnetism, or any combination of these,” the authors write. But “It’s a shockingly distinct pattern,” Ritter said.

See Beef Tack.

(Jason W. Johns et al., “Worldwide Hemisphere-Dependent Lean in Cook Pines,” Ecology 98:9 [2017], 2482-2484.)