We argue that a healthy urban forest contributes immensely to the sustainability of cities. The argument is based on a comprehensive array of values elicited from Canadians in several cities. To begin, we define the urban forest as inclusive of all the trees in the city and thus representing the predominant contributor to a city’s green infrastructure. Then we enumerate and explain the broad diversity of ways in which urban people value trees in the city. We, thus, show the myriad pathways by which trees contribute positively to any city’s social, economic, and ecological sustainability. Following a short summary of the ways in which trees may detract from people’s quality of life, we present promising management directions for urban-forest improvement, as we understand the situation in Canada. We conclude that all cities can enhance their sustainability by improving the urban forest.

A review of road-ecology literature suggests that impacts of forest roads on species and ecosystems begin during the road construction phase, but persist and accumulate well after a road is no longer in use. Over this time, impacts stemming originally from construction, but then also from the continued physical presence and human use of the road, follow complex multiple pathways ending in diminished species persistence. Yet in practice, road-impact considerations rarely extend beyond short-term issues related to road construction or beyond the spatial extent of the road corridor. Even when the range of potential impacts is recognized, managers rarely have a framework for assessing those impacts. This can be problematic, as informed decisions regarding the long-term, wide-ranging ecological consequences of road placement, design, and use can lessen the degree to which a road modifies the composition, structure, and function of forest ecosystems. This paper presents a conceptual framework for organizing, synthesizing, and applying our growing understanding of how roads affect forest ecosystems. The framework includes two parts: (1) a series of impact-hypothesis diagrams wherein ecological impacts are organized relevant to three phases of road existence: construction, presence and use; and (2) a five-step approach whereby ecological impact and road importance can be evaluated and a decision matrix used to determine appropriate mitigation strategies. Highlights of a case study conducted in southwestern Nova Scotia are presented to illustrate the applicability of the framework.

We observe ongoing weaknesses in the quality of science underpinning environmental impact assessment (EIA) in Canada. This is frustrating because approaches for strong scientific practice in EIA we...

During a time of rapid urban growth and development, it is becoming ever more important to monitor the carbon fluxes of our cities. Unlike Canada’s commercially managed forests that have a long history of inventory and modelling tools, there is both a lack of coordinated data and considerable uncertainty on assessment procedures for urban forest carbon. Nonetheless, independent studies have been carried out across Canada. To improve upon Canada’s federal government reporting on carbon storage and sequestration by urban forests, this study builds on existing data to develop an updated assessment of carbon storage and sequestration for Canada’s urban forests. Using canopy cover estimates derived from ortho-imagery and satellite imagery ranging from 2008 to 2012 and field-based urban forest inventory and assessment data from 16 Canadian cities and one US city, this study found that Canadian urban forests store approximately 27,297.8 kt C (− 37%, + 45%) in above and belowground biomass and sequester approximately 1497.7 kt C year⁻¹ (− 26%, + 28%). In comparison with the previous national assessment of urban forest carbon, this study suggested that in urban areas carbon storage has been overestimated and carbon sequestration has been underestimated. Maximizing urban forest carbon sinks will contribute to Canada’s mitigation efforts and, while being a smaller carbon sink compared to commercial forests, will also provide important ecosystem services and co-benefits to approximately 83% of Canadian people.