How do Trees Lift Water From the Ground?
Handout 21 of Biology 101
Professor Mayim Etzman
How do trees raise water
from their roots to the leaves? Trees have tall tiny diameter columns
made of cellulose called xylem. Water rises up the xylem by capillary
action. You can see these forces in action if you dip a paper towel in
a bowel of water and watch the water rise up out of the bowl and up the
paper towel. Another force that raises water is solar radiation which
vaporizes water inside leaves so that osmotic pressure pulls water into
the leaves. This process is called transpiration. It's important to keep
in mind that water is being pulled up to the top of the tree not
redwood tree in the picture below is over 300 feet high. It is truly
remarkable that redwood trees can lift water so high.