Urban Forest Urban Forest Hurricane Recovery Hurricane Recovery
ProgramProgramhttp://treesandhurricanes.ifas.ufl.edu
Selecting Wind Resistant
Trees:Coastal Plain
SpeciesMary DuryeaEliana Kampf
• Study• Methodology• Results• Lists of wind resistance• Recommendations for a healthy urban forest
Andrew165 mph1992
Georges
110 mph1998
Katrina125 mph2005Rita
120 mph2005
Ivan130 mph2004
Opal125 mph
1995
Erin85 mph
1995
Dennis120 mph
2005Charley145 mph
2004Puerto Rico
Louisiana
Mississippi
Alabama
Florida
Georgia
Hurricanes Measured in StudyFunding: FL DOT and DOF, USDA Forest Service
Jeanne120 mph
2004
• SE Coastal Plain
• Subtropical & Tropical
• Urban neighborhoods randomly chosen at point of landfall
• All trees along streets were measured• Standing, leaning or fallen• Measured dbh, height for palms• Defoliation, branch damage
Methodology
• Surveyed 240 arborists, urban foresters, forest scientists• Asked them to rank 160 tree species for wind resistance
Wind and Trees Survey
sand
live o
akSu
rviv
al (%
)
Tree Species
loblolly pine
american
SE magnolia
live o
ak
wax m
yrtle
sweet
gum
crape m
yrtle
dogwood
sabal palm
laurel oak
pecanred
maple
chinese
tallo
w*
sycamore
slash pine
water o
ak
Bradford pear
black ch
erry
SE red ce
dar
SE red oak
longlea
f pine
Carolin
a
sand pine
spruce
pine
tulip
poplar
0
10
20
30
40
50
60
70
80
90
100
laurelch
erry
holly
* prohibited species in Florida
LSD = 35%
ResultsHurricane Ivan
(130 mph)
Aver
age
Bran
ch L
oss (
%) spru
ce
pine
sycamore
SE red oak
laurel oak
SE red ce
dar
sweet
gum
chinese
tallo
w*
live o
ak
pecanwate
r oak
red m
aple
black ch
erry
SE magnolia
slash pine
longlea
f pine
sand live o
ak
Bradford pear
wax m
yrtle
dogwood
crape m
yrtle
loblolly
pine
American holly
sand pine
tulippoplar
0
5
10
15
20
25
30
35
C. laurel
cherr
y
* prohibited species in Florida
Hurricane Ivan (130 mph)
Tree species
LSD = 11%
Results
Bran
ch L
oss
( %)
0
5
10
15
20
25
30
35
Tree Diameter
P<0.0001
39-79 in.20-39 in.8-19 in.< 8 in.
Large trees do more poorly than
small trees
Surv
ival
(Rec
alcu
late
d) (
%)
* prohibited species in Florida
Tree Species
American
holly
wax m
yrtle
SE magnolia
crape m
yrtle
live o
ak
dogwood
sabal palm
slash pine
pecan
red m
aple
Bradford pear
laurel oak
water o
ak
loblolly
pine
black ch
erry
longleaf p
ine
chinese
tallo
w*
sycamore
SE red oak
SE red ce
dar
sand pine
C. laurel
cherr
y
spruce
pine
tulippoplar
0
10
20
30
40
50
60
70
80
90
100Hurricane Ivan
(130 mph)
sand live o
ak
sweet
gum
LSD = 25%
Results
Laurel Oak
• Rapid growing, short lived (mature at 50 yr)
• Light wood (0.56 g/cm3)• Damaging when it falls
Survival of Oaks in North FL
Sand live oak Live oak Laurel
Surv
ival
(%)
Erin (85 mph)
Dennis (120 mph)
Opal (125 mph)
Ivan (130 mph)
20
40
60
80
100
0
P<0.001
Hurricane
Sabal Palm
85 120 125 130 145Surv
ival
(%
)
Wind Speed (mph)
020406080
100
165
92%
93%
Erin Jeanne Opal
IvanCharley Andrew
Southern Magnolia
• 96%, 97%, 92% standing after Erin, Opal, Ivan
• Excellent survival rate even though it lost about 43% of its leaves
Southern Red Cedar
0
20
40
60
80
100
Surv
ival
(%
)
Wind Speed (mph)85 12
0125
130
Erin Dennis
Opal Ivan
Wind Speed
0
20
40
60
80
100
0
20
40
60
80
100
85 120 125 130 14585 120 125 130 145
Erin
Jeanne
OpalIvan
Erin Opal
CharleyIvan
Slash PineErin
JeanneOpal
CharleyIvan
Longleaf Pine
Sand Pine Loblolly PineOpal
Ivan
Surv
ival
afte
r Hur
rican
es (%
)
Andrew
165 165
Pines
Pines
• Dangerous to have large trees close to buildings• Medium to Poor wind resistance:
• Longleaf & Slash > Loblolly > Sand & Spruce pine• Continue to die after hurricanes:
• Ivan (130 mph): Lost an additional 2-3%• Charley (145 mph): Lost an additional 50%
Live Oak
Defoliates early –Leaf loss was positively correlated with survival(p<0.0001)
Strong wood – 0.8 g/cm3
Species with higher wood density survived better
and lost less branches (p<0.0001)
Strong roots
Native vs. Exotic Trees Su
rviv
al
(%)
Hurricane
********NS
Native speciesExotic species
020406080
100
Jeanne Ivan Charley
• 85 surveys (35%) were returned• Combining:
• our study results• survey• scientific literature
Lists of Wind Resistance
Wind and Trees Survey – Results
Scientific Name Common Name
Wind ResistanceHigh Medium Low
# % # % # % Total #
Liquidambar styraciflua
sweetgum 18 43 21 50 3 7 42
Magnolia grandiflora SE magnolia 44 83 8 15 1 2 53Pinus clausa sand pine 3 7 7 17 32 76 42Pinus palustris longleaf pine 23 59 11 28 5 13 39Pinus elliottii slash pine 16 26 35 57 10 16 61Quercus laurifolia laurel oak 3 4 26 39 38 57 67Quercus virginiana live oak 63 89 8 11 0 0 71Sabal palmetto sabal palm 71 99 1 1 0 0 72Phoenix canariensis Canary Island
date palm 49 89 4 7 2 4 55
Taxodium distichum bald cypress 59 91 6 9 0 0 65Taxodium ascendens pond cypress 40 91 4 9 0 0 44
Highest Wind ResistanceDicotsCarya floridana, FL scrub hickoryCornus florida, dogwoodIlex cassine, dahoon hollyIlex glabra, inkberryIlex opaca, American hollyIlex vomitoria, yaupon hollyLagerstroemia indica, crape myrtleMagnolia grandiflora, southern
magnoliaQuercus geminata, sand live oakQuercus laevis, turkey oakQuercus myrtifolia, myrtle oakQuercus virginiana, live oakPodocarpus spp, podocarpusVaccinium arboreum, sparkleberryConifersTaxodium distichum, baldcypressTaxodium ascendens, pondcypressPalmsButia capitata, pindo or jellyPhoenix canariensis, Canary Island datePhoenix dactylifera, dateSabal palmetto, cabbage, sabal
Medium-High Wind ResistanceDicotsAcer saccharum subsp. floridanum, FL sugar
mapleAcer palmatum, Japanese mapleBetula nigra, river birchCarpinus caroliniana, ironwoodCarya glabra, pignut hickoryCarya tomentosa, mockernut hickory Cercis canadensis, red budChionanthus virginicus, fringe treeDiospyros virginiana, common persimmonFraxinus americana, white ashLiquidambar styraciflua, sweetgumMagnolia virginiana, sweetbay magnoliaMagnolia xsoulangiana, saucer magnoliaNyssa aquatica, water tupeloNyssa sylvatica, black tupeloOstrya virginiana, American hophornbeanPrunus angustifolia, chickasaw plumQuercus michauxii, swamp chestnutQuercus shumardii, Shumard oakQuercus stellata, post oakUlmus alata, winged elmPalmsWashingtonia robusta, Washington fan
Medium-Low Wind Resistance
DicotsAcer negundo, boxelderAcer rubrum, red mapleAcer saccharinum, silver mapleCeltis laevigata, sugarberryCeltis occidentalis, hackberryCinnamomum camphora, camphor *Eriobotrya japonica, loquat **Eucalyptus cinera, silverdollar eucalyptusFraxinus pennsylvanica, green ashMorus rubra, red mulberryMyrica cerifera, wax myrtlePersea borbonia, redbayPlatanus occidentalis, sycamorePrunus serotina, black cherryQuercus alba, white oakQuercus phellos, willow oakSalix xsepulcralis, weeping willowUlmus americana, American elmConifersPinus elliottii, slash pinePinus palustris, longleaf pinePinus taeda, loblolly pine
Lowest Wind ResistanceDicotsCarya illinoensis, pecanLiriodendron tulipifera, tulip poplarPrunus caroliniana, Carolina
laurelcherryPyrus calleryana, Bradford pearQuercus falcata, southern red oakQuercus laurifolia, laurel oakQuercus nigra, water oak Sapium sebiferum, Chinese tallow ***Ulmus parvifolia, Chinese elmConifersJuniperus silicicola, southern red cedarxCupressocyparis leylandii, Leyland
cypressPinus clausa, sand pinePinus glabra, spruce pine
* Invasive, not recommended by University of Florida/IFAS** Caution: manage to prevent escape*** Prohibited in Florida (Fox et al. 2005)
Recommendations for a healthy urban forest
• Consider soil depth, water depth and compaction
When Establishing New Trees:
• Plant a mixture of species, ages and layers
• Plant trees from the highest and medium-high WR lists
• Give trees adequate rooting space: • small trees - at least 3 x 3 m• large trees - at least 10 x 10 m
• Plant trees in groups as opposed to individually
• Establish a structural pruning program early on
• Plant high quality trees
with good structure
• Give trees adequate aerial space when mature
• Consult with a certified arborist or urban forester
When Managing Older Trees:
• Remove hazard trees • Consider removing trees on the lowest WR list
• Know the life span of your tree
• Prune trees regularly• Be aware of root damage during construction
• Have tree health evaluated
Recommendations for a healthy urban forest