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.”
Zlinszky and his colleagues scanned trees in Austria and Finland with laser beams between sunset and sunrise. From the time it takes beams to bounce back from branches and leaves, they could measure the movements of each tree, in three dimensions and at resolutions of centimetres.
Sleep like a log?
Isn’t this just the opposite way of saying that plants turn toward sunlight during the day?
Interesting. I am very glad that I can’t hear their screams when I cut them down with a chainsaw.
Are they claiming that the tree relaxes it’s muscles during sleep? Because I think I see a problem ...
My flowering trees are in full bloom in the morning, and the blooms close up in the late evening. Trees do react to the times of day.
I remember reading fifty five years ago that plants have “feelings”, in controlled tests with electronic monitoring equipment.
Country folk have seen Morning Glories and Sun Flowers for quite some time.
Do you think the leaves just might weigh more at night because they collect dew on their surface? Obviously, the extra weight of all the leaf’s moisture would make the branch sag. But then I’m not a scientist, so what do I know?
I wonder if these scientists considered this might just be the effect sunlight / heat has on lumber. Heat a board to bend it by shrinking the cells in the wood.
They could have figured this out by simply getting out of the city for a while and observing what every country person sees all the time. But I suppose there’s no research grants for that.
“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.”
Indeed? I’ve been watching southern USA mimosa trees fold up their leaves at dusk since the 1950s.
citation:
http://www.britannica.com/plant/mimosa-tree
Mimosa pudica (sensitive plant) is sometimes grown as a novelty because its leaves quickly fold up when touched. Albizia julibrissin (mimosa, or silk, tree), a widely planted ornamental in the southern United States, folds its leaves together at dusk, decreasing by at least half the amount of leaf surface exposed to the atmosphere. The movement is caused by changes in water...
More like the branches reach up to the light during the day time.
Certain trees (maples, for example) will invert their leaves as rain approaches.