Trees can make a city prettier, that is true. But that’s not even their best asset. A growing amount of research suggests that planting more trees in urban areas, if done correctly, could save tens of thousands of lives around the world each year — by soaking up pollution and cooling down deadly heat waves.
In fact, as a report from the Nature Conservancy details, a well-targeted tree campaign could be one of the smartest investments a hot, polluted city can make. Which seems important, given that the world’s cities will add about 2 billion people this century, and they’re only getting hotter.
The use of trees and vegetation in the urban environment brings benefits beyond mitigating urban heat islands including:
- Reduced energy use: Trees and vegetation that directly shade buildings decrease demand for air conditioning.
- Improved air quality and lower greenhouse gas emissions: By reducing energy demand, trees and vegetation decrease the production of associated air pollution and greenhouse gas emissions. They also remove air pollutants and store and sequester carbon dioxide.
- Enhanced stormwater management and water quality: Vegetation reduces runoff and improves water quality by absorbing and filtering rainwater.
- Reduced pavement maintenance: Tree shade can slow deterioration of street pavement, decreasing the amount of maintenance needed.
- Improved quality of life: Trees and vegetation provide aesthetic value, habitat for many species, and can reduce noise.
Trees and other vegetation naturally cool the air around them by shading surfaces and releasing water vapour. Moreover, their leaves act as filters, reducing PM levels in the surrounding 30m by as much as one-quarter. It is a one-two punch of environmental action. Those trees would also prevent between 200 and 700 heat-wave deaths per year — with that number presumably going up over time as global warming unfolds.
That’s not all: because the trees would cool cities significantly, many households and businesses could end up using less energy for air-conditioning — reducing electricity use by between 0.9 and 4.8 percent and helping slow the pace of global warming. They can also retain stormwater, boost home values, and even have important mental-health benefits. Plus, they’d just look nice.
Our Tree experts can offer you their expertise on proper tree care during a heat wave. Pruning your trees in summer allows them to save up their energy to thrive and handle a heat wave better. Also, keep in mind that regular tree assessments are the best way to keep your trees healthy and strong no matter the weather conditions. Look after your trees as they will, in the end, look after you.