New research continues on the 24h circadian rhythm. This time, two scientists show us that even trees sleep. The cycle of activity and rest is vital for all life forms. The study performed on trees may have a significant contribution to the wood industry and forestry.

Scientists found evidence of biological day-night rhythms in a variety of creatures: fruit flies, mice, or even single-cell organisms. This should be a result of the fact that life evolved between the continual sequences of sunrises and sunsets.

The Tree Study

The present study used advanced technology (laser scanners) to determine modifications in shape for birch trees. One of the trees was in Austria; the other was in Finland. And the results were that trees sleep too, just like everyone and everything else.

During the night, branches came down with 10 centimeters. It was as if the tree was trying to relax. This movement began approximately 2 hours after sunset, and the branches came up again just before sunrise.

To control daytime duration and movements created by the wind, the two researchers chose to conduct the experiment in the month of September, near the vernal equinox, during a windless night.

Benefits and Conclusions

Authors say this is just a preliminary study, and they would like to replicate it to other tree species to be sure that this is indeed a general trend in the nature world.

One way to explain this downward movement at night is the fact that trees tend to drop their water pressure. There is no photosynthesis during night time, so trees preserve energy and do not raise their branches against gravity.

This research may lead to new explanations on how a tree uses water throughout the day, and when a tree has the highest and the lowest contents of water.

From an economical point of view, knowing when a tree has a low content of water will be useful in the timber industry, to cut down drying time. On the other hand, in the rubber industry trees with a high content of water are needed.

But until researchers find the answers to these questions, one thing is clear: during night time, water pressure inside the trunk decreases, branches move downwards, and trees sleep.

Image Source: Wikipedia