by Carson Fong
Although you cannot tell just by looking at them, trees are an integral part of cities. Not only do they provide beauty, joy and comfort in the hustle and bustle of the city, they also serve key functions that improve the physical and mental health of city dwellers while also saving them money. Here are seven ways that trees make cities better.
- Trees purify the air
Trees help improve air quality by absorbing harmful pollutants, like nitrogen dioxide, sulfur dioxide, and carbon monoxide – all of which come out of vehicle exhausts. These toxic gasses are then broken down within the tree. Trees can also catch particulate matter on leaves and stems, removing them from the air and allowing them to be picked up and dissolved when it rains. - Trees keep cities cool
Cities often suffer from the “heat island effect,” where concrete and asphalt absorb and retain heat, causing higher temperatures. Trees fight this with shade and evaporative cooling. They can significantly reduce surface and air temperatures, making cities more comfortable and reducing the demand for energy-intensive air conditioning. Some studies in places like Los Angeles and Beijing found that trees helped to reduce air conditioning use by 50%. - Trees reduce flooding and erosion
Trees have roots that can absorb lots of rainwater. This provides natural infrastructure and reduces the strain on municipal drainage systems during big storms. Tree roots also improve soil permeability, allowing rainwater to infiltrate into the ground and replenish groundwater supplies. - Trees provide habitats for wildlife
Trees can provide essential habitats for birds, insects, and other wildlife. Many types of birds, insects, and furry critters like squirrels all thrive in environments with trees. Trees contribute to the overall ecological balance of cities and enhance urban biodiversity. - Trees block out noise
Trees act as natural sound barriers by absorbing and deflecting noise. This helps reduce noise pollution from various sources like traffic and construction, creating more peaceful and enjoyable urban environments. - Trees make cities look better
Who doesn’t like the look of a tree-lined street? Trees contribute to the beauty of a city, softening the harsh lines of buildings and adding color, texture, and a variety of colours during the seasons to urban landscapes. In fact, research has linked being in the presence of trees to reduced stress levels. Trees help financially too. More attractive green spaces attract visitors, and properties with mature trees have been shown to have higher property values. - Trees reduce carbon emissions
Through photosynthesis, trees absorb carbon dioxide and release oxygen. This helps cities in the long run by reducing their carbon footprint and health and cost impacts due to climate change. In fact, recent research has found that trees in urban environments might be able to absorb more carbon dioxide than those deep in the middle of large forests.Trees quietly provide all these benefits to us, and are an important part of our cities. However, their benefits are only maximized when they grow into mature trees, which takes years. Mature trees need our support to help ensure they are preserved. Many of them are found on private property – you can check out our pilot study last year about the private urban forest in the Queen Alexandra neighbourhood to see what we learned and find out what you can do to help protect our urban forest.
References:
- “How trees clean the air.” One Tree Planted. Meaghan Weeden. November 5, 2021. https://onetreeplanted.org/blogs/stories/how-trees-clean-air
- “2.4 What changes can communities make to the built environment to reduce urban heat islands?” in Reducing urban heat islands to protect health in Canada. Government of Canada, Health Canada. April 29, 2020. https://www.canada.ca/en/services/health/publications/healthy-living/reducing-urban-heat-islands-protect-health-canada.html#a2.4
- “This simple addition to a city can dramatically improve people’s mental health.” We Forum. Mark McCord. April 6, 2021. https://www.weforum.org/agenda/2021/04/city-trees-reduce-stress-and-anxiety/
- “City Trees and Soil Are Sucking More Carbon Out of the Atmosphere Than Previously Thought.” The Brink. Jessica Colarossi. February 16, 2022. https://www.bu.edu/articles/2022/city-trees-and-soil-are-sucking-more-carbon-out-of-the-atmosphere-than-previously-thought/
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