What trees do at night? Sleeping, or otherwise relax. This is what emerges from the study conducted by a Finnish research institute, which has monitored thanks to a laser scanner the nocturnal movements of branches and leaves of two trees.The recently published study after observing announces it has found a relaxation" of the trees, which sag visibly, also a dedina centimeters, tall specimens for up to five meters.The research is entitled "Quantification of Overnight Movement of Birch (Betula pendula) Branches and Foliage with Short Interval Terrestrial Laser Scan"Sampled trees are really only two (and perhaps from this point of view we could expect a larger representative sample), two birches, one in Austria and one in Filanda have been calm and windless nights choices, behind autumnal equinox, so as to ensure the same illumination in both places.The changes detected have shown gradual and the lowest point was reach in a couple of hours from sunrise, when in fact the trees resumed vigor and awakened. The question then is: Is it the sun the wake of the trees or the plants are regulated by an internal clock? Scholars argue for the latter, because the branches were beginning to rejuvenate before dawn.The search will now be extended to other specimens and will serve to better understand the mechanisms of water use by trees