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If 5,500 trees fall in Pasadena: The 'Tree Failure' windstorm report

Los Angeles Area Hit With Powerful Santa Ana Winds

David McNew/Getty Images

A boy whose school was closed climbs fallen trees on Green Street after strong Santa Ana Winds that are cauing the worst local wind damage in decades on Dec. 1, 2011 in Pasadena.

Hold on to your hats, a 27-page report called the "Pasadena Windstorm Tree Failure Analysis" has been made public by the city's Urban Forestry Advisory Committee.

Prepared for the city's Department of Public Works, the study examines data on nearly 5,500 trees that were damaged in the historic windstorms  -- with wind speeds reaching 100 miles per hour within the City of Pasadena -- on November 30 and December 1, 2011.

An analysis of tree failures by the Davey Resource Group showed the city’s urban forest suffered "severe losses" with approximately 9% of the trees damaged in the high winds. Costs to the city are projected to be in the tens of millions of dollars with hundreds of light poles and buildings also damaged in the storm.

The City of Pasadena maintains that it maintains about 57,500 trees in over 64,500 city locations. The report asserts that the "unpreventable wide variety of damage to the urban forest structure" was primarily caused by wind intensity and direction, and that the existing tree maintainence program prevented more damage from occuring.