A Survey of Urban Tree Damage After a Major Ice Storm Event In Northwest Arkansas

On 26 January, 2009 during a freezing rain event lasting 12 hours, ice accumulations of up to 4 cm formed on trees at the University of Arkansas arboretum located on the main campus in Fayetteville causing extensive damage to the collection.  A survey was conducted in early February 2009 to access damage as related to tree species and a damage rating of 0 (no damage), 1 (minor peripheral twig damage), 2 (minor limb breakage to 10 cm in caliper), 3 (moderate scaffolding limb breakage with caliper greater than 10 cm  and minor trunk shearing), 4 (major scaffolding limb breakage with caliper greater than 10 cm and major trunk shear), to 5 (completely destroyed: tree removed) was assigned to each tree in the survey.  Tree species belonging to the families Ulmaceae and Aceraceae showed the greatest damage along with the genus Pyrus in the Rosaceae.  Mature specimens of several species of Quercus, normally considered resistant to ice damage, showed extensive damage with several individual specimens receiving a rating of 5, a complete loss. Species belonging to the Magnoliaceae, Aquifoliaceae, and Taxodiaceae, and certain members of the Pinaceae generally had minor to moderate damage.  Survey results indicate that while all species showed varying degrees of damage, observations suggest extensive damage was more closely related to tree age, general health, and prior scaffold training and management than to any particular species.  Tree damage with a rating of 4 or 5 was usually associated with limbs and branches that had bark inclusions, poor branching structure, or signs of internal wood decay.  Results of this survey will be used to help generate guidelines for local and regional tree species selection and urban tree management in areas prone to ice damage.