Most animals are known to grab at least 40 winks at some point in the day, but it seems trees also drop off to'sleep' during the hours of darkness. Researchers have found that trees relax and let their branches droop when the sun goes down. A collaboration of researchers from Austria, Finland and Hungary used laser scanners on fully grown trees to measure their'sleep movement'. Scientists have found that trees appear to'rest' at night. The figure on the left depicts the tree at night, while the mirrored figure on the right depicts the same tree during the day.
They don't snore, but might creak during their slumbers. For the first time, trees have been shown to undergo physical changes at night that can be likened to sleep, or at least to day-night cycles that have been observed experimentally in smaller plants. Branches of birch trees have now been seen drooping by as much as 10 centimetres at the tips towards the end of the night. "It was a very clear effect, and applied to the whole tree," says András Zlinszky of the Centre for Ecological Research in Tihany, Hungary. "No one has observed this effect before at the scale of whole trees, and I was surprised by the extent of the changes."
We spend about a third of our lives asleep, so you'd think we'd have a pretty good understanding of it by now, but there's still a great deal about sleep that scientists don't get. What purpose do dreams serve? Why do humans and other animals need to sleep at all? Well, a new study suggests that even trees get their snooze on at night. The report was published in the journal Frontiers in Plant Science.
Researchers in Europe scanned trees and found that their branches had a distinct tendency to droop by a small amount (at most 4 inches) in the evenings, after a long day's work of photosynthesizing and standing majestically. The researchers scanned two birch trees using lasers, one in Finland and one in Austria, and observed the drooping in both trees. The reasons for the drooping have yet to be determined definitively. One of the authors, András Zlinszky told New Scientist that it could be due to a drop in water pressure in the plant cells that occurs when photosynthesis stops after the sun goes down. They plan on eventually using the laser scanning technology to look at entire orchards or forests instead of individual trees.
It might seem as though trees spend most of their lives standing still – but, according to new research, they do a lot more moving than you'd think. Scientists have discovered the subtle'heartbeat' of trees and shrubs, using terrestrial laser scanning to measure the overnight movement of branches and leaves. While only some trees in the study were shown to follow a'sleep cycle,' in which their branches lowered at night and returned to their daytime position hours later, the researchers found that all of the trees displayed minute, periodic pulses. The discovery suggests trees are pumping water, the experts say. Scientists have discovered the subtle'heartbeat' of trees and shrubs, using terrestrial laser scanning to measure the overnight movement of branches and leaves.