Prioritized Damage Forms & Mitigation - Montgomery Parks
Trees Surviving Ice Storms:
Prioritized Damage Forms & Mitigation Dr. Kim D. Coder
Professor of Tree Biology & Health Care Warnell School of Forestry & Natural Resources University of Georgia, Athens, GA. USA
THICKEST ICE ACCUMULATION (IN.) ON UTILITY LINES (10 YEARS)
ICE ACCUMULATION FEDERAL 1948 MAP
MAJOR ICE STORMS PROPERTY LOSS > $1 MILLION 52 YEAR PERIOD
TOTAL MAJOR ICE STORMS DOLLAR LOSS 52 YEAR PERIOD
IN MILLIONS -- YEAR 2000 DOLLARS
PER ICE STORM DOLLAR LOSS 52 YEAR PERIOD
IN MILLIONS -- YEAR 2000 DOLLARS
ICE THICKNESS 50 YEAR ICE STORM
WIND GUSTS 50 YEAR ICE STORM
AREAS >5 MAJOR ICE STORMS
(>$1 MILLION PROPERTY LOSS)
53 YEAR PERIOD
FREEZING RAIN DURATION 74 YEAR PERIOD
ICE STORM ZONES 51 YEAR PERIOD
A = GREAT PLAINS B = LAKE STATES BELT C = NEW ENGLAND BAND D = SOUTHERN STRAP E = PACIFIC NORTHWEST
FREEZING RAIN
80%
ice event surface temperature between o o 34 F / 30 F
ICE ACCUMULATION
Additional Ice Accumulated Due To Height
ICE ACCUMULATION (simple formula)
Ice Weight pounds per linear foot
=
freezing rain inches X branch diameter X 0.434
Sperry-Piltz Ice Accumulation Index
ICE CAPTURE AREA ( both branch / twig surface area & branch diameter )
greatest percent change in small branches
Eastern North America > 16 studies
tree species susceptibility ice storm damage
species susceptibility values 1.0 = resistant 2.0 = intermediate 3.0 = susceptible
Tree Family Susceptibility To Ice Storm Damage MOST SUSCEPTIPLE
LEAST SUSCEPTIBLE
Tree Species Cited In More Than Six Studies
note susceptibility range !
MOST ICE STORM
RESISTANT
TREE SPECIES EASTERN NORTH AMERICA
MOST ICE STORM
SUSCEPTIBLE
TREE SPECIES EASTERN NORTH AMERICA
SOME TREE SPECIES MORE SUSCEPTIBLE THAN OTHERS (duh!)
ICE STORM IMPACTS ON TREES: MOST IMPORTANT CAUSES OF DAMAGE
(derived from 45 ice storm studies & 56 variables observed)
IDENTIFIED GENERAL TREE DAMAGE CATAGORIES 1.
STORM LOADS
2.
WHOLE TREE ATTRIBUTES & SITE CHARACTERISTICS
3.
INDIVIDUAL TREE COMPONENTS
Top 5 Causes Of Ice Storm Damage In Trees
Only one is management !
ICE STORM LOADS
ICE THICKNESS / WEIGHT --HIGHLY VARIABLE– FREEZING RAIN
CLIMATIC CONDITIONS LOCATIONS STORM DURATION MORE ICE -- MORE WEIGHT MORE FAULTS -- MORE FAILURES
100mm = 3.9in ice
70mm = 2.8inches
50% DAMAGED = 38mm = 1.5in
Top 15 Causes Of Ice Storm Damage In Trees
GREENWOOD STRENGTH / RESISTANCE TO BENDING density, MOR, MOE, fiber strength, strength indexes
Zero / None Zip ! NO correlation between greenwood strength / resistance to bending values & ice storm damage susceptibility
Most Important Causes Of Tree Ice Storm Damage Arboriculture Can Manage
ARBORICULTURE
TREE HEALTH CARE asymmetrical crowns canopy surface area branch & twig density poor branch architecture poor form
0.250 0.213 0.213 0.170 0.163
branch structure edge trees vines crown diameter codominant branching
0.159 0.149 0.125 0.125 0.096
wide branch angles lateral branch number opposite branching tip-weighted branches included bark
0.074 0.064 0.064 0.043 0.043
Conclusion
PRIMARY COMPONENTS OF ICE STORM DAMAGE TO TREES
ICE STORMS ARE COMING ! ARE YOU READY? ARE YOUR TREES?
Prioritized Damage Forms & Mitigation Dr. Kim D. Coder
Professor of Tree Biology & Health Care Warnell School of Forestry & Natural Resources University of Georgia, Athens, GA. USA
THICKEST ICE ACCUMULATION (IN.) ON UTILITY LINES (10 YEARS)
ICE ACCUMULATION FEDERAL 1948 MAP
MAJOR ICE STORMS PROPERTY LOSS > $1 MILLION 52 YEAR PERIOD
TOTAL MAJOR ICE STORMS DOLLAR LOSS 52 YEAR PERIOD
IN MILLIONS -- YEAR 2000 DOLLARS
PER ICE STORM DOLLAR LOSS 52 YEAR PERIOD
IN MILLIONS -- YEAR 2000 DOLLARS
ICE THICKNESS 50 YEAR ICE STORM
WIND GUSTS 50 YEAR ICE STORM
AREAS >5 MAJOR ICE STORMS
(>$1 MILLION PROPERTY LOSS)
53 YEAR PERIOD
FREEZING RAIN DURATION 74 YEAR PERIOD
ICE STORM ZONES 51 YEAR PERIOD
A = GREAT PLAINS B = LAKE STATES BELT C = NEW ENGLAND BAND D = SOUTHERN STRAP E = PACIFIC NORTHWEST
FREEZING RAIN
80%
ice event surface temperature between o o 34 F / 30 F
ICE ACCUMULATION
Additional Ice Accumulated Due To Height
ICE ACCUMULATION (simple formula)
Ice Weight pounds per linear foot
=
freezing rain inches X branch diameter X 0.434
Sperry-Piltz Ice Accumulation Index
ICE CAPTURE AREA ( both branch / twig surface area & branch diameter )
greatest percent change in small branches
Eastern North America > 16 studies
tree species susceptibility ice storm damage
species susceptibility values 1.0 = resistant 2.0 = intermediate 3.0 = susceptible
Tree Family Susceptibility To Ice Storm Damage MOST SUSCEPTIPLE
LEAST SUSCEPTIBLE
Tree Species Cited In More Than Six Studies
note susceptibility range !
MOST ICE STORM
RESISTANT
TREE SPECIES EASTERN NORTH AMERICA
MOST ICE STORM
SUSCEPTIBLE
TREE SPECIES EASTERN NORTH AMERICA
SOME TREE SPECIES MORE SUSCEPTIBLE THAN OTHERS (duh!)
ICE STORM IMPACTS ON TREES: MOST IMPORTANT CAUSES OF DAMAGE
(derived from 45 ice storm studies & 56 variables observed)
IDENTIFIED GENERAL TREE DAMAGE CATAGORIES 1.
STORM LOADS
2.
WHOLE TREE ATTRIBUTES & SITE CHARACTERISTICS
3.
INDIVIDUAL TREE COMPONENTS
Top 5 Causes Of Ice Storm Damage In Trees
Only one is management !
ICE STORM LOADS
ICE THICKNESS / WEIGHT --HIGHLY VARIABLE– FREEZING RAIN
CLIMATIC CONDITIONS LOCATIONS STORM DURATION MORE ICE -- MORE WEIGHT MORE FAULTS -- MORE FAILURES
100mm = 3.9in ice
70mm = 2.8inches
50% DAMAGED = 38mm = 1.5in
Top 15 Causes Of Ice Storm Damage In Trees
GREENWOOD STRENGTH / RESISTANCE TO BENDING density, MOR, MOE, fiber strength, strength indexes
Zero / None Zip ! NO correlation between greenwood strength / resistance to bending values & ice storm damage susceptibility
Most Important Causes Of Tree Ice Storm Damage Arboriculture Can Manage
ARBORICULTURE
TREE HEALTH CARE asymmetrical crowns canopy surface area branch & twig density poor branch architecture poor form
0.250 0.213 0.213 0.170 0.163
branch structure edge trees vines crown diameter codominant branching
0.159 0.149 0.125 0.125 0.096
wide branch angles lateral branch number opposite branching tip-weighted branches included bark
0.074 0.064 0.064 0.043 0.043
Conclusion
PRIMARY COMPONENTS OF ICE STORM DAMAGE TO TREES
ICE STORMS ARE COMING ! ARE YOU READY? ARE YOUR TREES?
