Site Assessment
Robert J. NorthropExtension Forester
Right Tree‐Right Place Florida Urban Forest Council
Seeing the forest for the trees
and visa versa
City In the ForestSite AssessmentVaries by Geographic Scale
•Single tree•City•Ecological region
Site AssessmentSingle Tree – Below Ground
1. Soil pH2. Soil texture3. Soil drainage4. Soil volume5. Soil bulk density6. Built infrastructure
Site AssessmentSingle Tree – Below Ground Soil pH
Site AssessmentSingle Tree – Below Ground Soil texture
Site AssessmentSingle Tree – Below Ground Soil drainage
Site AssessmentSingle Tree – Below Ground Soil volume
Site AssessmentSingle Tree – Below Ground Soil bulk density
Site AssessmentSingle Tree – Below Ground
Below groundurban infrastructure
Site AssessmentSingle Tree – Above Ground
1. Buildings and other structures2. Overhead utility lines3. Signs and lights4. Paved surfaces
Site AssessmentSingle Tree – Above Ground
Buildings and otherstructures
Site AssessmentSingle Tree – Above Ground
Overhead utilities
Site AssessmentSingle Tree – Above Ground
Signs and lights Site AssessmentSingle Tree – Above Ground
Paved surfaces
Site AssessmentSingle Tree – Environment1. Cold hardiness2. Available sunlight3. Artificial light4. Amount and periodicity of rainfall5. Prevailing wind patterns6. Strong storms7. Air pollution8. Salt
Site AssessmentSingle Tree – Environment
Cold hardiness
Site AssessmentSingle Tree – Environment
Available sunlight Site AssessmentSingle Tree – Environment
Artificial light
Site AssessmentSingle Tree – Environment
Amount and periodicityof rainfall
Site AssessmentSingle Tree – Environment
Prevailing wind patterns
Site AssessmentSingle Tree – Environment
Strong storms
R2 polyn = 0.8004
y = 0.0044x2 - 0.7886x + 47.035
0
5
10
15
20
25
30
35
40
75 95 115 135 155 175
Wind Speed (mph)
Urb
an F
ore
st L
oss
(%
)Site AssessmentSingle Tree – Environment
Air pollution
Site AssessmentSingle Tree – Environment
Salt Site AssessmentSingle Tree – Environment
1. Wildlife2. Tree litter3. Diseases and insects
Site AssessmentSingle Tree – Environment
Wildlife Site AssessmentSingle Tree – Environment
Tree litterand pollution
Site AssessmentSingle Tree – Environment
Diseases and insects Site AssessmentCitywide
1. Diversity vs. Monocultures2. Native vs. exotic3. Invasive species4. Transportation corridors
Site AssessmentCitywide
Diversity vs monocultures
Percent of Top Ten Species in the City of Tampa (total # stems)
red mangroveBrazilian pepper
black mangrove
cabbage palmetto
live oak
white lead treelaurel oak
All others
darlington oak
Carolina laurelcherry
white mangrove
Site AssessmentCitywide
Native vs non‐nativeand invasive species
Site AssessmentCitywide
Transportation corridors Site AssessmentEcological Region
Conservation of regional biological diversity
Natural Design and Urbanization?
• Vigorous and diverse
• Actively regenerating
• Nutrient assimilating
• Temperature regulating
• Deliberately patterned
• Resistant and resilient
The future of our forest ecosystems
Site Assessment
Robert J. NorthropExtension Forester
Right Tree‐Right Place Florida Urban Forest Council