Resilient Trees Training Materials

1. Learn about the program

The Operation Resilient Trees project is part of a larger partnership between the Earthwatch Institute and research scientists Peter Ibsen and Dr. Darrel Jenerette from UC Riverside. The goal of the project is to support scientific research about how well urban trees cope with heat and water stress across Southern California. Review both videos below to find out the role community scientists can play in providing critical field data for these research efforts:

Program Overview (9 minutes)

The Science (17 minutes)

2. Learn what to measure

Successful Resilient Tree data collection involves mapping individual trees from the right species and collecting six different kinds of information from each tree:

A. Identify the correct tree species

B. Determine tree is healthy

C. Take photos of the tree

D. Get a GPS location

E. Measure tree diameter (DBH)

F. Measure tree canopy size

G. Measure % permeable surface around the tree

Identify the correct tree species
  • Review our video presentation covering all 10 species covered by the Resilient Trees 3.0 study. (Specific species ID help begins at minute 9:05).

Tree Species Training

  • AND review the Resilient Trees 3.0_Tree Key ID.
  • Self-test your ability to identify the species accurately with our Resilient Trees 3.0 Species Quiz.  Want an even bigger challenge?  Try our Resilient Trees 3.0 Memory Game
  • Optional/Additional Study: there are also many online resources that have more detailed information on each of these tree species and how to identify them when in the field. We have listed some on our Resources page.  Our guides are based on iNaturalist, but there are many more out there. Consult these resources, or any reference books on tree identification if you would like to study this further.
B. Determine tree is healthy

For this study, we are only interested in trees that are in good to excellent condition.

  • A good rule of thumb is to ask yourself whether you would plant that tree in your own yard. Here are the more technical descriptions of what we’re looking for:
    • Excellent – no major structural problems, no significant mechanical damage, may have only minor aesthetic insect, disease, or structure problems, yet is in good health.
    • Good – The tree may have: minor structural problems, mechanical damage, significant damage from non‐fatal or disfiguring diseases, minor crown imbalance or thin crown, or stunted growth compared to adjacent trees or shrubs. This condition can also include trees that have been topped, but show reasonable vitality and show no obvious signs of decay.
  • Self-test with our Tree Condition Quiz
C. Take photos of the tree

In every photo (if not using iNaturalist in the field), include a sheet of 8.5 x 11″ paper or similarly-sized dry-erase board listing the Date_Time_Recorder Name as listed on the data sheet (e.g. 1/15_11:03am_John Smith would indicate that the photo belongs to the tree John Smith measured at 11:03am on January 15th).  Take pictures of the following:

  • Close-up of a leaf (so we can see the shape)
  • Close-up of the bark (so we can see the color and texture)
  • Any fruits, nuts, pods, or flowers
  • A portrait of the overall tree which allows us to see the canopy shape and surrounding area.  Place your dry-erase board or sheet of paper at the base of the tree so we have a reference for scale.  (This allows us to determine tree height).

For a printable version of these instructions, review our Camera Protocol_Resilient Trees PDF.

Methods for Uploading Photos:

Option 1- If you are using iNaturalist on your iPhone or Android phone in the field, take a photo of the tree there (no dry-erase board necessary)- it’s very easy!  There are specific instructions on the video tutorials we created for you on our Collect Data using iNaturalist page around minute 3′.

Option 2- If you are not using iNaturalist, continue to take photos with your phone or camera.  In every photo, there should be a sheet of paper or dry-erase board listing the recorder name and date/time the tree was measured which will allow us to track down which photos belong to which tree.  Upload all the photos to Dropbox or other photo-sharing site which allows public access to the photos via a weblink.  Include the weblink in your Excel template where listed.

D. Get a GPS location

GPS Coordinates Presentation

Depending on what device you’ll be using to take GPS measurements, you’ll also want to review the following resources:

How to measure with a dedicated GPS device

E. Measure tree diameter (DBH)

If you do not have a dedicated DBH (diameter at breast height) tape, you can always just measure the circumference of the tree at breast height (4.5 ft/54 inches off the ground) in inches with a regular measuring tape and leave the diameter column blank on your data collection form and the lab will do the math to get diameter for you.

How to measure DBH

F. Measure tree canopy size

Now it’s time to measure the tree canopy (how far the branches extend), measured as a length in all four cardinal directions. This is so the research scientists can draw an approximate polygon to determine how big the canopy is.

How to measure tree canopy width

G. Measure % permeable surface around the tree

To measure this, you will need your ~33ft string to visualize a circle around the tree, and estimate how much surface within the circle is permeable.

How to measure permeable surfaces

3. Pass the written test

  • Ready to prove your understanding of the concepts? Take our online, ten-question, multiple-choice test and pass with a 80% score or higher to qualify for a field test:  Resilient Trees 3.0 Summary Exam
    • The exam is administered through a 3rd party website called ClassMarker. If you have any technical difficulties taking the test, please consult their User Guide.
    • Once you pass, sign up for a Field Test event near you (generally held at the same time as the Volunteer Events), or contact Ellie Perry at to be assigned a reference park.

4. Prepare to collect and record data

Congratulations on your certification.  You are now ready to collect data:

  • Review the contents of our Resilient Trees 3.0 Dropbox folder.  Read the Certified Community Scientist Instructions document contained within first for full instructions on collecting your own tools, or borrowing an Earthwatch toolkit near you, as well as which templates to print/use before going out into the field.
  • Plan where you will go.  If you’re in the Coastal-Central region, TreeMapLA has a good summary inventory of tree locations. We have access to several city-specific tree inventories as well, so contact Ellie Perry at if you need help finding trees to measure in your region.

Review our Submit Data page to discover your options for submitting your data once collected.

5. Team Leader Training (optional)

If you’re planning to lead groups into the field, review our training materials on how to guide volunteers safely and suggestions for facilitation:


Visit our Measuring Trees Training page for some helpful videos about iNaturalist and taking measurements.

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