Most living organisms adapt their behavior to the rhythm of day and night. Plants are no exception: flowers open in the morning,some tree leaves close during the night. Researchers absorb been studying the day and night cycle in plants for a long time: Linnaeus observed that flowers in a dark cellar continued to open and close, and Darwin recorded the overnight movement of plant leaves and stalks and called it "sleep". But even to this day, and such studies absorb only been done with small plants grown in pots,and nobody knew whether trees sleep as well. Now, a team of researchers from Austria, and Finland and Hungary measured the sleep movement of fully grown trees using a time series of laser scanning point clouds consisting of millions of points each.
Source: phys.org