Healthy Trees,
Healthy Cities
Phone App
Healthy Trees, Healthy Cities Healthy Trees, Healthy Cities
Creating a culture of stewardship that engages urban youth and community members in the planting, care, and stewardship of urban trees and forests to improve
the health of people and their communities
Apple and Android App Stores
“Healthy Trees Healthy Cities”
What does the app do?
The HTHC app has 5 modules:
1. Tree Stewardship
2. Pruning
3. Tree Health Monitoring
4. Early Pest Detection
5. Tree Planting
What is the information used for?
NATIONAL LOCAL PERSONAL
Year Trees Plots Trees/plot Miles Surveyed
2015 3646 58 62.8 29
2016 2084 35 59.5 17.5
New YorkYear Trees Plots Trees/plot Miles Surveyed
2015 2690 100 26.9 50
Philadelphia
Species # Trees
Honey Locust 902
London Plane Tree 634
Callery Pear 389
Ginkgo 347
Pin Oak 341
New YorkSpecies Found = 94
Species # Trees
London Plane Tree 343
Plum/Cherry 314
Norway Maple 206
Red Maple 191
Honey Locust 133
PhiladelphiaSpecies Found = 86
Most Common Species Most Common Species
2016: 7,000 Trees Surveyed w/ Casey Trees
Washington, D.C.
Summary
Sample Design
Early Signs
Later Signs
Tree 36
Stress Index -0.783
Tree 71
Stress Index -.409
Tree 45
Stress Index -0.191Tree 77
Stress Index 0.81
Tree 65
Stress Index 1.3
Tree 75
Stress Index -0.009
ത𝑋 (𝑧𝑣𝑖𝑔𝑜𝑟 + 𝑧𝐷𝑒𝑓𝑜𝑙 + 𝑧𝐷𝑖𝑒𝑏𝑎𝑐𝑘 + 𝑧𝑇𝑟𝑎𝑛𝑠𝑝𝑎𝑟𝑒𝑛𝑐𝑦 + 𝑧𝐷𝑖𝑠𝑐𝑜𝑙𝑜𝑟)
Tree Stress Index
Urban Tree Health Monitoring
Non-Stressor Specific Evaluation of Tree Health
Variable Notes
Discoloration Visual estimate
Defoliation Visual estimate
Transparency Digital estimate
Dieback Visual estimate
Crown Vigor Visual estimate
Red Maple
Healthy StressedStress Index
(n = 107)
(n = 191)
• Both cities show a similar range
in tree stress for red maple
street trees.
• 20% of red maples in both cities
have a stress index greater than
1.6.
Red Maple in
Philadelphia and New York
% o
f tr
ees m
easure
d
Honey locust
London plane
Red maple
40% of red maples have no fine twig
dieback while only 19% of honey locust
have 0% fine twig dieback.
Most trees regardless of
species have less than 30%
fine twig dieback.
Fine Twig Dieback
% o
f tr
ee
s m
ea
su
red
% Fine Twig Dieback
Healthy StressedStress Index
Transparency
Dieback
Discoloration
Defoliation
Results from a healthy
red maple.
Healthy StressedStress Index
Transparency
Dieback
Discoloration
Defoliation
Results from a
stressed red maple.
2D Graph 2
Stress Index
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
% o
f tr
ees m
easure
d
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Zallscore vs Z_prob
Zallscore vs Z_prob
2D Graph 2
Stress Index
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
% o
f tr
ee
s m
ea
su
red
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Zallscore vs Z_prob
Zallscore vs Z_prob
Healthy StressedStress Index
2D Graph 2
Stress Index
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
% o
f tr
ee
s m
ea
su
red
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Zallscore vs Z_prob
Zallscore vs Z_prob London plane street trees (2015-2016).
2D Graph 2
Stress Index
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
% o
f tr
ee
s m
ea
su
red
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Zallscore vs Z_prob
Zallscore vs Z_prob London plane street trees flooded during
hurricane Sandy. Measured 2 years post
Sandy (2014).
Example:Detecting new tree health issues.
QUESTIONS
Thank You!