These Trees Know Where They Are on the Planet

Most trees grow straight, but the Cook pine leans another way. As a new study reveals, the tree leans toward the equator no matter where it grows, giving it what Science Alert calls a "drunken-looking slant." Matthew Ritter of California Polytechnic State University first became curious about the trees after noticing specimens in both California and Hawaii were leaning southward. But when he spoke to researchers in Australia, he was surprised. There, Cook pines leaned in the opposite direction. A study of 256 Cook pines on five continents soon after revealed more than 91% leaned toward the equator, per Science World Report, with an average tilt of 8 degrees, or twice that of the Leaning Tower of Pisa.

But the farther it is from the equator, the more the tree leans: One Cook pine in southern Australia has a 40-degree tilt. The tree appears to be "sensing where it is on the planet," Ritter tells CBC News. "That has never been seen ever in any plant, let alone trees." It's possible the Cook pine leans toward a light source, as many plants do, but that some sort of abnormality keeps Earth's gravitational pull from straightening it out, reports Discover. Or as researchers write in Ecology, the lean could be a response to "annual sunlight, gravity, magnetism, or any combination of these." Whatever the reason, it's "a scientifically interesting thing" and shows "plants are responding to their environment in ways we don't understand," Ritter says. (Poland's Crooked Forest is still a mystery.)