The Grim Reefer shares a report from Live Science: Once a mighty kauri tree — a species of conifer that can grow up to 165 feet (50 meters) tall — the low, leafless stump looks like it should be long dead. But, as a new study published today in the journal iScience reminds us, looks are only surface-deep. Below the soil, the study authors wrote, the stump is part of a forest “superorganism” — a network of intertwined roots sharing resources across a community that could include dozens or hundreds of trees. By grafting its roots onto its neighbors’ roots, the kauri stump feeds at night on water and nutrients that other trees have collected during the day, staying alive thanks to their hard work.
Using several sensors to measure the movement of water and sap (which contains important nutrients) through the three trees, the team saw a curious pattern: the stump and its neighbors seemed to be drinking up water at exact opposite times. During the day, when the vibrant neighbor trees were busy transporting water up their roots and into their leaves, the stump sat dormant. At night, when the neighbors settled down, the stump circulated water through what was left of its body. The trees, it seemed, were taking turns — serving as separate pumps in a single hydraulic network. So, why add a near-dead tree to your underground nutrient highway? While the stump no longer has any leaves, researchers wrote, it’s possible that its roots still have value as a bridge to other vibrant, photosynthesizing trees elsewhere in the forest. It’s also possible that the stump joined roots with its neighbors a long time ago, before it was, well, a stump. Since nutrients still flow through the stump’s roots and into the rest of the network, the neighboring trees may never have noticed its loss of greenery.