100 Escobedo et al.: Hurricane Debris and Damage Assessment Arboriculture & Urban Forestry 2009. 35(2): 100–106 Hurricane Debris and Damage Assessment for Florida Urban Forests Francisco J. Escobedo, Christopher J. Luley, Jerry Bond, Christina Staudhammer, and Charles Bartel Abstract. A random 10% sample of communities in highly-impacted counties from the 2004 and 2005 Florida, U.S. hurricane seasons were used to study tree debris generation and damage from seven hurricanes. Woody debris amounts in cubic meters (m3 (cubic yards; yd3 generation per 30.5 m (100 ft) of street segment ranged from 0.59 m3 age, and 17.47 m3 (22.85 yd3 ) for low damage, 3.4 m3 (4.44 yd3 ) for high damage levels; cost of removal and disposal averaged $28.25 per m3 ($21.47 per yd3 ) ) as well as rates and costs for cleanup, tree removal and pruning were obtained for these events. Average debris (0.77 yd3 ) for moderate dam- ). Most communities used unit costing to account for tree removal and pruning rates, averaging 2% and 28% of street trees, respectively. Tree canopy, wind speed, and percentage of urban developed land all had a significant effect on debris amount. Florida communi- ties with a greater tree density generated decreased amounts of debris during the 2004 and 2005 hurricane season. These results can be used to help communities plan for hurricane management activities and estimate potential damages to their tree resource. Key Words. Emergency Management; Hurricane; i-Tree; Tree Pruning; Tree Removal; Urban Forest Management; Wind Damage. Studies in Florida (U.S.) and elsewhere have documented the impact of hurricane force winds on urban forest structure, dam- age to woody vegetation, harm to forested landscapes, and of the varying resistance of different tree species (Duryea 1997; Duryea et al. 2007a; Duryea et al. 2007b; Everham and Brokaw 1996; Francis and Gillespie 1993; Gresham et al. 1991; Mayer et al. 2007; Oswalt and Oswalt 2008). Studies have also demonstrated that hurricane winds and storm surges can severely damage indi- vidual trees and landscapes, causing trees to defoliate, partially break, drop branches, topple, or uproot (Duryea et al. 2007a; Francis and Gillespie 1993; Gresham et al. 1991). Hurricanes can also alter the structure and function of ecosystems (Kupfer et al. 2008; Oswalt and Oswalt 2008). To effectively plan and man- age hurricane-prone urban forests in Florida, the effects of wind storms must be taken into consideration (Escobedo et al. 2007). The aftermath of a hurricane often includes a large amount of debris from infrastructure or landscape damage, which may result in the need to prune or remove hurricane-damaged trees (FEMA, 2007a). The cost of cleaning up debris and the reme- diation of tree damage is borne by local communities, but may be offset if a declaration of a federal disaster is made by the President of the United States, which hedges costs through reim- bursement programs as designated by the Stafford Act (FEMA, 2007b). The ability to quantify tree debris to be removed and oth- er tree-related costs quickly and accurately after a storm impacts the reimbursement monies requested by the Federal Emergency Management Agency (FEMA) and, indirectly, the communities’ relations with FEMA during the recovery operation. Methods that estimate tree-related debris and damage from ice storms have been used to develop protocols and tools to assist commu- nities with post-storm recovery activities (Bloniarz et al. 2001). Non-sediment hurricane debris is generally categorized, and in certain cases reimbursed, in two broad categories: clean wood, and construction and demolition (FEMA, 2007a). Al- though models from the United States Army Corps of Engineers ©2009 International Society of Arboriculture (USACE) estimate that hurricane-generated debris consists of 30% clean woody debris, state emergency services reported that up to 70% of the debris removed after Hurricane Floyd in North Carolina was composed of vegetation (COES, 2005). Fol- lowing Hurricane Ivan in September 2004, Escambia County, Florida reported that almost 90% of all hurricane debris re- moved was composed of vegetation (Escambia County, 2004). Debris removal and disposal is an enormous problem for storm-affected communities. For example in 1992, 11.5 million cubic meters (15 million cubic yards) were reported following Hurricane Andrew (Ward 2002). A report from mid-2006 stated that more than $1 billion had been spent in the state of Florida for Hurricane Wilma recovery efforts alone, and that $2.3 bil- lion had been sent to Florida up to that point for the 2004 storm season (FEMA, 2006a). Typically, about half of such recov- ery costs were likely due to debris management (Ward 2002). There are few methods in existence for accurately estimating urban forest debris following hurricanes. Currently, the USACE debris estimation model produces a debris estimate for an af- fected area based on the number of households and categories for heavy, medium, and low amounts of vegetation (FEMA, 2007a). This model is acknowledged to have an error of nearly 30%. Elsewhere, Broward County, Florida developed a Geographical Information Systems (GIS) based Hurricane Debris Estimation Tool that accounts for tree and palm debris (Umpiere and Mar- goles 2005). The tool uses tree and palm cover and assumes a tree to palm ratio and debris volume per affected tree, per unit area. The FEMA HAZUS hurricane module uses tree density and tree height data to derive tree-loss curves for estimating downed tree debris following hurricanes (FEMA, 2006b). How- ever, the tree-loss curves only consider trees greater than 9.14 m (30 ft) in height. Validation using actual tree debris esti- mates showed that this model over-estimated tree debris by ap- proximately 90% in Virginia and 41% in North Carolina states (FEMA, 2006b). A standardized method for estimating ice
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