UC Master Gardener Program
UC Master Gardener Program
UC Master Gardener Program
University of California
UC Master Gardener Program

Save Trees during Drought with New Tree Ring Irrigation Contraption (TRIC)

From a majestic oak, giant sequoias or a swaying palm there is nothing quite as beautiful in this world than a tree. They can provide us with shade, fruit, flowers and most importantly are the “lungs of planet”.  While we have enjoyed some wet weather over the last week, California is still suffering from extreme drought conditions.

Prioritizing Trees for Landscape Water Use

Many residents have been encouraged to reduce water use by turning off their outdoor watering systems, but this may be causing stress to established trees that are becoming increasingly thirsty for water.

In most traditional residential landscapes trees are surrounded by turfgrass. Turfgrass surrounded trees take advantage of the frequent and shallow watering schedule, typically set to help the lawn flourish. When residents eliminate or reduce water for lawns, trees cannot easily adapt to the new water shortage.

“Mature fruit trees and landscape trees are worth saving! Recognizing early signs of drought stress is important because irreversible damage can occur that no amount of watering will correct.” said Janet Hartin, UC Cooperative Extension advisor in a recent article, Save Water, But Also Save Trees During a Drought.

Replacing small plants, lawns and shrubs is easy compared to a large tree which takes years to become established. Saving mature trees during a drought should be a top priority in your landscape water use allocation.

“Two seasons without enough water can result in severe drought stress and even kill a tree,” warned Hartin. “Also, drought-stressed trees are more prone to damage from diseases and insects than non-stressed trees.”

Understanding how to water a tree effectively is important to avoid water waste and to ensure that the tree is receiving the correct amount of water for its survival.

One key factor to successfully watering a tree is understanding what soil type is present. Understanding soil types is an important factor in determining how much water is stored in the ground. For example, sandy soils dry out quickly while clay soils retain more water. Contact your local UC Master Gardener Program to learn how to determine your soil type.   


Figure 1 - Graphic adapted from Harris et al. 2004
Another important factor is understanding tree anatomy for watering (see Figure 1). The tree roots of a mature tree are found in the top three feet of soil and extend outside of the tree's canopy. This outside area of the tree roots is the most active absorption area.

Tree Ring Irrigation Contraption (TRIC)

Recently the Calif. Center for Urban Horticulture (CCUH) at UC Davis, UC Division of Agriculture and Natural Resources (ANR) and Ewing Irrigation devised a unique watering system called the Tree Ring Irrigation Contraption (TRIC).   Using previous data from Netafim drip tube tables and from the Irrigation Association Landscape Irrigation Auditor manual, the partners envisioned a possible solution to mitigating drought conditions and the effect on landscape trees.  The TRIC is an inexpensive kit that homeowners can put together for around $100 for one large tree.  

The TRIC could enable homeowners to adequately water trees to a depth of three feet with confidence, by using the recommended parts and using the TRIC calculator with accurate information. Aside from a recommended parts list, there is a “plug-in” calculator created by Dr. Loren Oki, UC ANR Associate Specialist in Cooperative Extension Landscape Horticulture for UC Davis & UC ANR. The TRIC calculator helps determine the run-time needed for the device.

Learn more by visiting:

Posted on Thursday, December 4, 2014 at 8:52 AM

Comments:

1.
How often do you need to water to the 3' depth?

Posted by Paula Glogovac on December 5, 2014 at 11:03 AM

2.
Watering frequency depends on a number of factors - the big ones being the size of the tree and the evapotranspiration rate. There is an excellent overview with examples of calculating watering frequency at http://homeorchard.ucanr.edu/The_Big_Picture/Irrigation/. For more information about evapotranspiration, check out the CIMIS (CA Irrigation Management Information System) website at http://www.cimis.water.ca.gov/.

Reply by Missy Gable on December 5, 2014 at 1:08 PM

3.
I subscribe to many of the UCANR and MG blogs... this shows as a blog in the URL... but I either don't subscribe to the appropriate blog or I missed it... what blog would I typically find articles of this type?  
 
CHEERS

Posted by Stephen I Morse on December 9, 2014 at 10:27 AM

4.
My oversight... found the blog...  
used almost same sources for an item at the Contra Costa MG newsletter...  
 
 
CHEERS

Posted by Stephen I Morse on December 9, 2014 at 10:31 AM

5.
So glad to see more attention to our landscape trees. Thanks!!!!

Posted by Robin Y Rivet on December 10, 2014 at 4:33 PM

6.
the concept of watering to the dripline has always been a best practice...do you really think people will pay $100 for each tree? why not provide the information free of charge to encourage people to take care of their trees (and if they want to buy TRIC - then offer that as an option)...i have 30 trees on my property - and there is no way i could pay $100/tree...

Posted by Lisa Rini on March 2, 2015 at 8:08 PM

7.
Hi Lisa, CCUH and the UC Master Gardener Program are not selling the TRIC, the information on how to build the TRIC is provided in the article with a parts list. On average the supplies needed to make the TRIC are approx. $100. If you download the hyperlinked PPT presentation above you will see a price breakdown of the supplies on page 8. Best, Melissa

Reply by Melissa G. Womack on March 3, 2015 at 8:21 AM

8.
Why couldn't the use of a soaker hose accomplish the same result? I believe rating for most at .9 gal/hr. I realize these are not pressure compensating, but certainly more affordable for average homeowner. Also, the 1/2" inline emitter tubing could be used, I believe. Your thoughts appreciated. Thanks for posting! Tom V

Posted by Thomas Vineski on April 1, 2015 at 4:03 PM

9.
There are a number of reasons that soaker hoses are not appropriate for this use but the main one is that they do not deliver water at a precise rate. In-line drip tube has emitters for at a specified rate and are spaced in regular intervals. The manufacturers publish tables of water delivery rates for each type of drip tube. Soaker hoses are too imprecise and there are no such tables for soaker hoses. We need to be precise in determining the amount of water we provide for irrigation since we are now so limited by our water supplies. We no longer have the luxury of saying "close enough".  
 
The only way that I would agree that a soaker hose is okay to use is if there was a water meter used to only provide a specific volume of water through the soaker hose. That volume to apply would need to be calculated using some of the methods used to calculate the irrigation duration and length of the in-line drip tube in the TRIC spreadsheet.

Posted by L. Oki on April 1, 2015 at 4:40 PM

10.
Thank you Dr. Oki for your explanation. What would be recommended value for decomposed granite soils? Thank you.

Posted by Tom Vineski on April 20, 2015 at 8:47 AM

11.
My london plane tree is planted 4 feet from the street. What configuration should i use for the netafim since i cannot encircle the tree, which has a diameter of approximately 18 feet.  
 
Thanks.

Posted by Elizabeth Traylor on May 14, 2015 at 5:57 PM

12.
Decomposed granitic soils wight also contain small amounts of other soil types and organic matter. Without seeing other details of your soil, "sand/fine sand" would probably be best. If you want to find out what your specific soil type is, use the "SoilWeb" UC application at: http://casoilresource.lawr.ucdavis.edu/gmap/ Just be aware that there is WAY more information about soils here than you probably wanted to see!  
 
Loren

Reply by Marcy Sousa on June 2, 2015 at 8:05 AM

13.
You'll have to do the best you can to apply water to the tree roots. You'll have to make a guess as to where the roots are and lay the drip tube appropriately. Since the tree is only 4 feet from the street, hopefully there is a larger landscaped area on the other side of the tree. You can start laying the drip tube closer to the tree than the directions indicate, about 6 feet from the tree trunk, and progress outward to and past the drip line of the tree canopy.  
 
This might also prevent you from using the total recommended length of tubing. Should this happen, reduce the calculated runtime proportionally: For an 18' diameter tree canopy, 2 lengths of drip tube are recommended. If you end up using only one length of tubing, then reduce the runtime by half. I just means that you will have to irrigate more frequently. Watch the tree for water stress symptoms. If small twigs and leaves start to wilt and don't recover the next morning, apply another irrigation right away.  
 
Loren

Reply by Marcy Sousa on June 2, 2015 at 8:05 AM

14.
This is a reply from Loren Oki:  
You'll have to do the best you can to apply water to the tree roots. You'll have to make a guess as to where the roots are and lay the drip tube appropriately. Since the tree is only 4 feet from the street, hopefully there is a larger landscaped area on the other side of the tree. You can start laying the drip tube closer to the tree than the directions indicate, about 6 feet from the tree trunk, and progress outward to and past the drip line of the tree canopy.  
 
This might also prevent you from using the total recommended length of tubing. Should this happen, reduce the calculated runtime proportionally: For an 18' diameter tree canopy, 2 lengths of drip tube are recommended. If you end up using only one length of tubing, then reduce the runtime by half. I just means that you will have to irrigate more frequently. Watch the tree for water stress symptoms. If small twigs and leaves start to wilt and don't recover the next morning, apply another irrigation right away.  
 
Loren

Reply by Marcy Sousa on June 2, 2015 at 8:06 AM

15.
Hi Tom, the previous reply is actually from Loren and I just posted it for him. Have a great day!

Reply by Marcy Sousa on June 2, 2015 at 8:12 AM

16.
Thank you so much Dr. Oki and Marcy. This is very helpful. Fortunately, there is a amply landscape area away from the street to lay the drip line, so these modifications should work.  
 
Thanks again for taking time to address my problem.  
 
Liz

Posted by Elizabeth Traylor on June 2, 2015 at 12:38 PM

17.
I see in the pictures that the drip tubing is on top of the landscape (grass). In my backyard we have grass around our 2 trees, for which we would like to apply the tubing. In order to mow the grass, it seems that you would have to pick up the drip tubing each time you mowed. Any suggestions as to how to mow and hold up the tubing?

Posted by Nancy King on July 22, 2015 at 4:36 PM

18.
I am not seeing how often younwould water to this depth. Also, what calculator would one use for a tree with less than a 4 ft radius, as with my newly planted trees. Also, can .9 gph Netafim be used, or would it be best tomreturn and exchange my .9 gph rolls for .6 gph?  
 
Many thanks for a reply

Posted by b wagoner on November 6, 2015 at 3:57 PM

19.
I am not seeing how often younwould water to this depth. Also, what calculator would one use for a tree with less than a 4 ft radius, as with my newly planted trees. Also, can .9 gph Netafim be used, or would it be best tomreturn and exchange my .9 gph rolls for .6 gph?  
 
Many thanks for a reply

Posted by b wagoner on November 6, 2015 at 3:58 PM

20.
As a San Diego Master Gardener I have received questions about watering trees using a hose end sprinkler. I have recommended that they should be careful to avoid run-off, and use a catch can to check how much water is being applied. It seems that this would be much easier for the average homeowner than building a TRIC. Thoughts? Is there a calculator that I can direct people to for how many inches of water to apply to wet the soil to 2 - 3' ? It would need to take soil type into account, of course. Watering frequency information would be helpful as well.

Posted by Dawn Standke on January 2, 2016 at 5:30 PM

21.
Hi Dawn,  
TRIC and RSIC (http://ccuh.ucdavis.edu/public/drought/rotary-system-irrigation-contraption-rsic/RSIC) systems aren't for everyone but we want to make sure to present available options as we look to preserve our landscape trees during months with no/limited rain. The recommendations you are giving are another option for tree care. Here is a link to irrigation tips during drought: http://cagardenweb.ucanr.edu/Drought_/Drought_Irrigation_Tips_/. Check out the resources compiled under 'Irrigation Scheduling Worksheet'.  
Thanks for everything you do!  
Missy

Reply by Missy Gable on January 4, 2016 at 7:55 AM

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