Urban Forest Hurricane Recovery Program

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Urban Forest Hurricane Recovery Program
http//treesandhurricanes.ifas.ufl.edu
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Lessons Learned From Hurricanes
Mary Duryea Eliana Kampf
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Hurricanes Measured in Study
Funding FL DOT and DOF, USDA Forest Service
Georgia
Alabama
Mississippi
Louisianna
Florida
Puerto Rico
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• Lessons and recommendations about
• Urban forest
• Trees (for example species and structure)
• Soil and rooting conditions
• Final recommendations for a healthy urban
  forest

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The higher the wind speed of the hurricane, the
more likely trees will fail
Lessons About The Urban Forest
Lesson 1
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Urban Forest Loss Also Depends on

• Tree species, age, health, and structure

• Conditions during the hurricane such as
  precipitation and the time to move through an
  area

• Site characteristics such as soil conditions (for
  example soil depth and moisture)

• Urban forest conditions such as overall tree
  canopy and composition

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Recommendation Establish and manage a healthy
urban forest to improve wind resistance by
Lessons About The Urban Forest

• Choosing more wind resistance species

• Having a comprehensive
• tree management plan

• Having a structural pruning program for
  young and mature trees

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Trees in groups survive winds better than trees
growing individually
Lessons About The Urban Forest
Lesson 2

• 80 versus 70 survival in Ivan
• 88 versus 78 survival in Jeanne

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Recommendation 1Plant trees in groups (at least
5) as opposed to individually
Lessons About The Urban Forest
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Recommendation 2 Plant a variety of species,
ages and layers of trees and shrubs to maintain
diversity in your yard and community
Lessons About The Urban Forest
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Some tree species are more wind
resistant
than others
Lessons About Trees
Lesson 1
Bald cypress
Sand pine
95 survived Hurricane Charley
Only 4 survived Hurricane Jeanne
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Recommendation 1Plant tree species which have
been found to tolerate wind better than others
Lessons About Trees
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Recommendation 2 Consider removing trees that
are on the lowest wind resistant lists
(especially if they are over-mature and
endangering lives or property)
Lessons About Trees
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Lessons About Trees
Recommendation 3 When a tree fails or is
removed, plant a new tree in its place
Bagdad FL
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Lessons About Trees
Recommendation 4Become familiar with the
recommended tree species and how they perform in
natural and urban ecosystems in your community
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Palms survive hurricanes better than dicots and
conifers
Lessons About Trees
Lesson 2
Cabbage palms are good survivors
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Lessons About Trees
Queen palms, though, are poor survivors
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Lessons About Trees
Recommendations

• Consider planting wind resistant palm
  species

• Monitor palms carefully
• after the storms

• Allow at least 6 months for palms to put
  out new
• growth

restorable
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Pines may show no immediate visible damage after
a hurricane but may decline over time
Lessons About Trees
Lesson 3
Pines can die slowly over a period of 6 months to
2 years
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RecommendationMonitor pines carefully
Lessons About Trees

• Look closely for insects

• Look for signs of stress or poor health

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Lessons About Trees
Lesson 4
Trees that lose all or some of their leaves are
not necessarily dead
Research shows that trees that lose leaves
survive winds better (e.g. live oak gumbo limbo)
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Lessons About Trees
Recommendation Wait, watch for leaves and
monitor trees health
Note Some species, such as pines, may not
recover if defoliated
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Lessons About Trees
Lesson 5
Native tree species survived better than exotics
in south Florida hurricanes
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Lessons About Trees
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Lessons About Trees
Lesson 6
Older trees are more likely to fail in hurricanes
The larger and older a tree is, the more branches
it will lose.
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Lessons About Trees
Recommendations

• Know the life span of your urban tree
  species

laurel oak, for instance, only lives 50 years!!!!

• Remove over-mature trees that present a
  hazard to people and property

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Unhealthy trees are predisposed to hurricane
damage
Lessons About Trees
Lesson 7
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Lessons About Trees
Recommendations

• Avoid damage to tree trunks

• Remove hazard trees before the wind does

• Have a certified arborist or urban forester
  check for signs of disease and decay they
  are trained to advise you on tree health

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Trees with poor structure or included bark are
more vulnerable in the wind
Lessons About Trees
Lesson 8
This co-dominant leader failed in Hurricane
Katrina
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Lessons About Trees
Recommendations

• Plant high quality trees with central
  leaders and good form

• Follow with a preventive structural pruning
  program of both young and mature trees

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Lessons About Trees
Lesson 9
Well-pruned trees survive better than
unpruned trees
Trees Standing After Hurricane ()
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Lessons About Trees
Recommendations

• Begin a preventative pruning program

• Select the right tree for the right location

• Give trees adequate aerial space
  considering their crown size

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Lessons About Soil and Rooting Conditions
Lesson 1
Trees with more rooting space survive winds better
Campuses, Parks, Yards
Yards, Parks
91 survival
Street trees, Parking lots, Yards
73 survival
64 survival
0 to 3 m2 (0 to 39 ft2)
4 to 7 m2 (40 to 75 ft2)
gt 7 m2 (gt 75 ft2)
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Lessons About Soil and Rooting Conditions

• Give small trees at least 10 by 10

• Give medium trees
• at least 20 by 20

Recommendation Give trees enough rooting space
according to their mature size

• Give large trees
• at least 30 by 30

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Lessons About Soil and Rooting Conditions
Lesson 2
Good soil properties with adequate soil depth,
deep water table, and no compaction help wind
resistance
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Lessons About Soil and Rooting Conditions

• A healthy root system will
• Maintain a healthy tree
• Anchor the tree

Recommendation Soil depth needs to be (ideally)
3 deep with a deep water table and no compaction
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Lessons About Soil and Rooting Conditions
Lesson 3
Trees with damaged root systems are more
vulnerable to the wind
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Lessons About Soil and Rooting Conditions
Recommendations

• Be careful not to damage roots
• during construction

• Be aware that when tree roots are
• cut, its anchoring system may be harmed
  and compromised

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We need a healthy urban forest with
Final Considerations

• Species age diversity

• An informed
• public

• Good rooting
• space soil
• properties

• Good cultural practices

• Wind resistant species

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Planting
Final Considerations
Remember When a tree fails, plant a new one in
its place!
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Older tree management
Final Considerations
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A Healthy and Wind Resistant Urban Forest
Final Considerations

• Conserves energy and lowers utility bills

• Improves air quality

• Provides shade and cooling

Vs.

• Increases property values

no trees

• Benefits health

• Reduces flooding and erosion

• Mitigates hurricane force winds