Understanding and Assessing Impacts
Increasing summertime temperatures and extended heatwave events, such as the 2018 heatwave, demonstrated that particular communities are more vulnerable to heat-related illness and death. The people who died during the heatwave were generally low-income, elderly, and living alone. In Montreal, as in many other urban centres, tree cover is higher in historically wealthier areas. Low-income areas, typically with higher proportions of visible minorities and lower education and income levels, generally experience less tree coverage. Increased tree cover in these areas would help cool the air and provide a refuge during heatwaves, and potentially save lives.
Surrounded by rivers and heavily urbanized, Montreal is prone to inland flooding. As precipitation increases with a changing climate, people and infrastructure will face increasing risk of flash floods and overflowing rivers. Preserving and enhancing natural habitats in and around cities contributes to reducing these risks by allowing water to return to the ground.
Forests do not have to be big to deliver big value. Their value continues to grow as cities seek to address converging challenges of population growth, climate change, and biodiversity loss. The benefits of urban forests include:
- Capture greenhouse gases
- Lower air temperatures
- Decreased flood risk
- Increased biodiversity
- Cleaner air
- Food security
- Improved general health
Recognizing the importance of its urban forest to mitigate the impacts of climate change, the City of Montreal mapped its tree canopy index, the ratio of tree crowns or groups of trees (the canopy) to the total urban area, using aerial photography from June 2007 for every municipality on the island. The initial index was set at 20.3 percent of tree canopy and was the basis for the Plan d’Action Forêt Urbaine that followed, setting tree planting goals by land use for each of the boroughs and cities.