Five minutes are enough to take a look at this amazing video. It is extremely well done and it tells you about things that you would never have suspected. How can it be that trees exist? Well, it turns out that their metabolism is truly alien and it exploits physical phenomena that you wouldn't have imagined could be used in that way. But Mother Gaia has many tricks!
One point that has fascinated me most is how this behavior of threes highlights a fundamental characteristic of holobionts: the individual organisms that form the holobiont do not act with a purpose, they do not have "in mind" to benefit the group. But, if it is true that what's good for the hive is good for the bee, also the reverse is often true. And especially in this case.
Trees pump water by evaporating water, which means they lose most of it. From the video, you'll learn that just about 5% of the pumped water is used by the tree for its needs. The rest evaporates away -- it is the process of evapotranspiration.
So, trees are highly inefficient pumping machines. But, curiously, this inefficiency is what benefits the forest. This huge evaporation is what puts in motion another pump: the biotic pump. It is a mechanism that generates a depression that, in turn, pulls water from the humid atmosphere near the sea all the way to the inner areas of the forest. Without this mechanism, forests could hardly exist inland.
