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Data
layers needed:
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•Street network
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•Population
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•Tree canopy
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•Critical facilities
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Tree
risk zones:
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•Trees
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•Roads & streets
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•Occupancy
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•people
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•places or sites (buildings)
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Risk
zones are based on the principal component of transportation as it affects
public safety and response. Street
segments (i.e. from intersection to intersection) are the primary component
of analysis; but the tree canopy resolution (e.g. 30 meters) determines the
detail of the final UTRI rating map.
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The tree
canopy layer substitutes initially as the “trigger” for areas of potential
risk (related to vegetation).
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These
characteristics are ranked and then summed ( a GIS process) to create rating
for each street segment.
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The “No
target, No risk” concept applies for disaster planning. Targets in the disaster context are
narrowly defined.
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In
addition, streets and facilities with little or no tree canopy are rated as
“low risk” in the UTRI model.
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Disaster-related
outcomes from a well designed and implemented tree risk management plan, or
from the UTRI “fast track”.
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Outcome
based measurements & evaluation:
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•Increased public safety
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•Improved tree health
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Indicators
(for measurement):
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•Decline in number of high-risk trees over time
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•Reduction in number of trees needing hazard
pruning
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•Reduction in number of “interruptions” during a
disaster
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•Reduction in storm damage (debris)
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