This document summarizes a study comparing tree surveys conducted virtually using Google Street View imagery to traditional field surveys. The virtual survey identified 606 trees across 10 miles of streets, matching 93% of the 597 trees found in the field survey. Genus identification agreed for 90% of trees while species identification agreed for 66% of large, common trees. The virtual survey resulted in tree counts and sizes that were around 10% lower than the field survey. While not a replacement for field surveys, the study finds virtual surveys can provide a free and easy method for coarse tree inventory data collection and updating existing inventories.

1. How well does a virtual
street tree survey work?
Dr. Adam Berland Ball State University

2. http://vision.caltech.edu/registree/
L.A. wants Caltech and Google to count the city's trees
-LATimes July 27, 2016

3. Can we generate quality data
using a virtual survey in GSV?
© 2016 Google

4. Cincinnati suburbs
Mt. Healthy
Reading
Wyoming
Field data (2013)
All trees on >10% sample
of local streets
Virtual survey analyst:
Bachelor’s in field botany

5. © 2016 Google

6. RESULTS
10 miles of street length
Field survey 597 trees
Virtual survey 606 trees
93% ‘matched’
Time mismatch for field/virtual

7. Genus agreement: 90%
Species agreement: 66%
Large, common, distinctive
© 2016 Google

8. Berland & Lange (in review)
1-to-1 line
Regression
line
Slope = 0.79
R2 = 0.80

9. Imagery © 2016 Google

10. 0
100,000
200,000
300,000AnnualBenefits($)
Virtual Field
i-Tree Streets: Virtual survey ~10% lower than field survey

11. Performance recap
Tree count / location
Tree ID
Size (DBH)
© 2016 Google

12. © 2016 Google

13. Recommendations
Does not replace field surveys
Free & easy approach
Coarse variables
Update existing inventories

14. Questions / comments / ideas
Adam Berland
amberland@bsu.edu