By Jode Roberts, Communication Specialist at David Suzuki Foundation
Imagine a sleek contraption for your backyard so powerful it has the cooling effect of 10 air conditioners, quietly filters dust, allergens, and pollutants, runs for free on solar power, and its only byproduct is oxygen.
Dream no longer. This elegant machine is a healthy, mature tree.
Using only energy from sunlight, a tree can soak up almost 400 litres of water from the ground each day, and cool the surrounding air through transpiration. Trees absorb airborne contaminants and breathe out clean oxygen. They’re such efficient air filters that Columbia University researchers estimate that for every 343 trees added to a square kilometre, asthma rates in young people drop by about 25 per cent.
What else can these handy natural contraptions do for us? The US Forest Service says trees near buildings can reduce air-conditioning needs by a third and, because they break the wind, can save up to half the energy used for heating. According to the University of Washington’s Center for Urban Horticulture, mature tree canopies reduce the air temperature of urban areas between five and 10 degrees Celsius.
Imagine replacing these ecological services with human-built substitutes. While we can easily handle cooling a room or building, creating a city-sized air conditioning unit that could reduce the temperature of an urban area by 10 degrees is an almost unimaginable engineering feat that would require massive amounts of energy.
These types of sophisticated services that nature provides are not only misunderstood and under-appreciated; they tend to be ignored in modern economics and urban planning. When a forest or wetland is converted to another use, decision-makers tend to focus on traditional metrics like infrastructure costs, property values, and future contributions to the tax roll.
Thus, we continue to deplete natural resources and degrade nature in and around urban areas, failing to recognize the contribution of ecosystem services – like clean air, fresh water, and cooling – to the economy and health of communities.
While economists, ecologists, and decision-makers grapple with how to estimate an appropriate economic value for nature’s benefits, I am hopeful that the field will spur communities to consider the true value of their natural riches. In the meantime, we should all pitch in and help beat the heat by investing in natural capital in our own backyards – a tree for your yard or park.
For more information about natural capital, check out davidsuzuki.org/naturalcapital
Learn more at www.davidsuzuki.org