Integrating sustainability subsystems in the management of urban forests

The urban forest is an important natural capital asset providing essential ecological, social, and economic benefits to people living in cities. Research contained within this dissertation examines urban forest structure and management through the lens of strong sustainability and has as its central focus the question of where to prioritize planting of trees in a densely populated, and continually expanding, North American urban centre. Three independent research studies are included, each of which addresses a dimension of the urban forest that falls within one of the three subsystems of sustainability. The first study focuses on urban forest ecological service delivery with a specific focus on the relationship between forest canopy closure and summer surface temperatures across the City of Toronto, Canada. The second study examines a social dimension of the urban forest—identifying distributional inequalities in city resident access to urban tree canopy as a function of their household income. In the third study, an economic dimension of urban sustainability is investigated by examining the legacy of street tree planting decisions and their relationship to ash tree mortality caused by the emerald ash borer (Agrilus planipennis). In addition to adding to scholarship concerning the processes and relationships examined within each sustainability subsystem, common themes arising across each of the studies are identified and discussed. These individual research studies and intersecting themes serve as the basis for an innovative approach to prioritizing urban tree planting that seeks to integrate a sustainability subsystems approach to the decision-making process.