Tree Health in Phoenix, Arizona, U.S.
Chris A. Martin and Jean C. Stutz
Abstract: Two studies of tree diversity, visual health, and mortality in the Phoenix, Arizona, U.S. metropolitan basin were conducted as part of the Central Arizona Long-Term Ecological Research project. For one study, tree diversity, mortality, and visual health were determined in 2010 at 204 sites, encompassing both the Phoenix metropolitan basin and in the surrounding Sonoran Desert. In another study, records of tree visual health and mortality were taken during the winter months (2003–2007) at 65 non-residential sites across an urban to rural gradient. Average tree mortality rates were 4.2% per annum. Crown condition was rated as very good or good for the majority of trees. Poor pruning practices and abiotic injuries, such as trunk sunscald, were observed on 70% and 23%, respectively, of trees in non-residential areas. Disease and pest problems were detected in 41% of urban trees, including wood decay, Verticillium wilt, sooty canker, and ash decline. Based on these data, researchers suggest that urban forest health in Phoenix is being negatively impacted by extensive wounding of trees, particularly in non-residential settings, possibly caused by excessive crown manipulation through pruning.
Keywords: Arizona; Phoenix; Tree Diversity; Tree Mortality; Urban Forest; Urban Heating.