Amount of water use by trees...HELP!!!

Tom Dunlap

Tom Dunlap

Here from the beginning
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Retired in Minneapolis
Help me with my homework, please!

I need to have some sound data that shows how much water trees uptake/use/respirate, etc. If I had more time I would love to do the research to find the information. since time is lacking, I'm asking for some help with this homework. Someone must have links to some good research that quantifies how much water trees need to live.

At work they have bought a bunch of 20 gallon 'gator bags'n to try and water the trees. Since we're weeks into a severe drought I know this is like trying to fill a swimming pool with a shot glass. In order to make a point about watering with much more water than 20 gallons every other day I need good data.
 
Here is an example from A Text Book of General Botany Smith, Gilbert, Bryan, Evans and Stauffer.

On the basis of the rate of water loss of apple shoots observed in Illinois during July, it appears that a single mature apple tree may loose 95 gallons of water per day.

one other point from the same book is the most active cells in plants are 85 to 98% of water by weight. Water is almost constantly being lost by evaportation of cells of the aerial parts.

How about applying an anti-desiccate?
Careful of plant sensitivities.

Hope this helps!
 
This morning I had more time for research.

here are some cut/paste tidbits that I gleaned:

From Kim Coder

1-3”/week
5 gal/sq.yd

For every 18 degree F increase in temperature, almost twice as much water evaporates from the tree.

In tree leaves, wilting is the first major symptom of water loss excesses and heat loading. Leaves
under heavy heat loads may progress through senescence (if time is available), brown-out and finally abscise. Leaves quickly killed by heat are usually held on a tree by tough xylem tissue and the lack of abscission zone preparation. Rewatering after heat damage and drought may initiate quick leaf abscission.

As a general rule, each temperature step, beginning at 40oF and continuing to 58oF, 76oF, 94oF,
112oF, and 130oF each allow physical doubling of respiration and water loss. Gross photosynthesis generally doubles up to 94oF and then rapidly falls-off. Heat stroke is a series of metabolic dysfunctions and physical constraints that pile-up inside trees and become impossible to adjust, avoid or correct.

U of NM extension:

The amount a tree withdraws may vary from a gallon or less for a young tree to as much as 150-250 gallons per day in a fully mature tree. This water demand is the tree's peak (maximum) water use on the hottest day of the summer.

http://aces.nmsu.edu/pubs/_h/h-636.html

Anecdotal:

"A mature oak tree can draw up to 50 or more gallons of water per day."

"Mature trees can consume up to 15 gallons of water per hour on a hot
day." (360 gallons)

10 gallons per caliper (diameter) inch.

Texas Forest Service

60 gallons per 10-foot by 10-foot area

Young, newly-planted trees should be watered three times a week. During each watering, they need 5 gallons of water for every inch of stem — or trunk — diameter, which is measured 6 inches above the ground. So if your tree measures 6 inches in diameter, that’s 30 gallons of water, three times each week

City of Austin:

For each inch of trunk diameter (width across) measured at knee height, the tree will need about 5 gallons. A 12” tree, then, would need about 5 x 12 = 60 gal of water.

Time: When you hand water using a hose at medium pressure, it will take approximately 2.5 minutes to produce 5 gallons of water. For example, a 10” diameter tree should have a total watering time of 10” x 2.5 minutes = 25 minutes.

Adjust the watering time according to the method of application. Using a drip or soaker hose will take significantly more time to release 5 gallons of water than an open hose at medium pressure. Consider performing your own experiment at home to determine your application rate! Feel free to email us with your results.
 
I don't have any links but my old boss, who has done some of the largest transplants in the U.S., told me that a tree in water stressed conditions, which could be drought or root loss, should get 1 gallon per inch of caliper per day.
 
As is evidenced by the quotes you printed, Tom, and the other responses, watering advice is all over the map. Obviously where you live, the species and the weather all play a role. I have always recommended an inch per week when not raining here in central TX, but again, so many variables impact that rule of thumb.

I'll be seeing Don Gardner at the ISA conference in Waco this week. He is going to bring me a paper he wrote that details his advice. If you are going to that conference, he or I can give you this then.

One thing that has been driving me nuts this summer is the number of folks who have heard that the best way to water trees is by putting a ring of soaker hose at the drip line and letting it run overnight. Works great for the roots in that vicinity, but seeing as how with a mature live oak that could easily be 50 feet or more from the trunk, it doesn't do much for the rest of the root system, which I would argue is the vast majority of it. Don agrees that this is not sufficient for most mature trees. We both recommend uniformly watering the entire area under the canopy. I would add that you should minimize water immediately around the root flares.

But as to quantity, Don recommends enough water to penetrate to 5 inches deep. He says the Texas Forest Service is recommending a depth of 6 to 8 inches, but I haven't seen their recommendation personally.
 
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