Transcript:

Okay, one bar of atmospheric pressure is about 10 meters of water, which is 30 feet. So, how does one atmosphere push up water to the top of a 300-foot tree? There is not enough force to do it.

The way the tree does it to pull up water 300 feet is ingenious. When the trees are saplings, it starts creating these series of pipes that are interconnected called the xylem network, and the size is between 20 to 800 microns.

And this xylem is continuously filled with a column of water. It's a continuous column of water. So, as the tree is growing, it is allowing water to transpire across the leaf. So, the leaf is letting the water molecule evaporate, and that creates a suction. And that suction force is what pulls the next molecule of water up and up and up.

But then you think, wait a minute, but eventually, the water column should break because the molecules will not stay together. It turns out that the water has a very high cohesive force. So about 25 atmospheres it can sustain as a continuous column of liquid. And that is how water reaches 300 feet by transpiration.

It is an ingenious method.