Climate change vulnerability assessment of the urban forest in three Canadian cities

Climate change is a likely addition to the unpredictable challenges urban communities will face. Enhancing urban forests has gained prominence as a climate adaptation tool in cities. The fact that urban forests are also vulnerable is now starting to emerge. Many urban forest management professionals do not know how to take climate change into account and what aspects of urban forest vulnerability to climate change to prioritize. Bringing climate change to the forefront of the decision-making process in urban forest management, and urban forests to the forefront of urban climate issues, is important to urban forest success. This paper presents an exploratory assessment of vulnerability to climate change in the Canadian urban forests of Halifax, London, and Saskatoon. The objectives of the assessment were to: 1) identify the elements of urban forest exposure and sensitivity to climate change, the nature of the expected impact, and the adaptive capacities that exist in these three urban forests; 2) assess which of these elements contributes more to urban forest vulnerability to climate change; and, 3) elicit adaptive strategies based on this information. The method used was participatory and expert-based and allowed for a systematic evaluation of vulnerability. Exposures related to drought, heat stress, and wind, susceptibility of urban trees to insects and diseases, and the sensitivity of young trees and tree species with specific temperature and moisture requirements, are the main concerns regarding the vulnerability of urban forests to climate change in these three cities.