Published on 09/07/00

Understanding Water Important in a Drought

Trees Surrounded by Water They Can't Use

We talk about water, drink water, flush water, spray water and use water every imaginable way. But what is this stuff?

Pure water clear, with no color, taste or odor. It tends to bind closely to itself or bead up. Its properties make it both unusual chemically and critical biologically.

Every school child can recite water's chemical formula, H2O, which means a single water molecule is composed of three atoms bound together.

Two of the three are small hydrogens, each with a single negatively charged electron shell surrounding a positively charged proton center.

The third atom is a massive oxygen, which can partially capture and hold the two negatively charged electrons away from the two hydrogens. Oxygen grabs and hordes electrons while still sharing them a little.

Here's the neat part. The loss of a negative electron shell leaves the positive proton partially exposed on each hydrogen. And the almost continual holding of the two negatively charged electrons adds a greater negative charge to the oxygen atom.

Water: It's Magnetic

That's important. The oxygen molecule's ability to steal electrons from its hydrogen partners generates a partial charge separation within the molecule. So the water molecule has a positive end and a negative end, like a magnet.

Since positive charges stick to negative charges, water molecules link together. This unique linkage process, found in few other elements, allows water to have many valuable special attributes essential for life.

Because of this linkage between water molecules, water is slowed from evaporation, it's able to dissolve many things and it floats when frozen.

And because each water molecule tends to stick closely to its neighbor, if one is pulled, others will follow. That special bond allows water to be pulled from the soil to the top of trees 300 feet tall.

Neat, huh?

When it comes to managing trees, water is both the problem and the solution. It's critical to understand it if we're to effectively manage our trees and their water resources.

(For more information on water, what it is and how it works in trees, visit the University of Georgia School of Forest Resources Web site at /library. Click on "Service & Outreach," then "Information Library," then "Drought Information.")

Kim Coder is a forester with the University of Georgia Warnell School of Forestry and Natural Resources.