Why must we keep trees in our cities?

figs-laman-street-canopyBefore the storm that tore through our city on the night of Monday 20th April wreaking havoc in its path, nobody would have even asked that question.

But now, many of us feel less certain about trees; we’ve had our power cut, or our roof has been smashed, or we’ve had no running water for days. Or, you could be like me, who escaped pretty well unscathed, but you feel the insecurity anyway because so many of your friends and neighbours were badly affected.

The storm was undoubtedly a wake-up call that we need to take our climate seriously and take whatever measures are necessary to protect our living spaces. Trees that are clearly dangerous can and will be removed under current Newcastle Council policies. For the rest, the vast majority of our trees, it is now time to assess their value to us.

The crucial fact that needs highlighting is that trees provide an indispensable safeguard to the health and resilience of our cities.

Without trees our city would be hotter, more polluted, subject to more intense flooding, devoid of much wildlife, and would be a more stressful place to live. What’s more, Newcastle’s attractiveness as a tourist destination would fall to almost zero and land values would plummet.

Wyong Council’s decision to allow residents almost free rein to cut down trees is a knee-jerk reaction to the storm. The decision fails to consider the mountain of evidence that trees provide measurable and diverse benefits to any city. Those benefits will be irreplaceably lost when the trees go.

The most beautiful cities of the world have recognised the vital contribution trees can make. Urban forest strategies spell out how a city can be made more liveable through well-planned, extensive tree planting. In the US, cities like New York, Seattle, and Washington DC, have urban forest management policies involving  ”prolonged and profound investments in the health of their urban forests”. London and Edinburgh have long had policies of extensive tree plantings in parklands and streets.

New York City has suffered four major storms in the last decade. The latest and most destructive, Superstorm Sandy, cut a swathe through the city on 29th October 2012. New York lost 20,000 trees and suffered US$19billion damage. Replanting and further forestation of the urban environment are key factors in New York City’s recovery plan.

Scientific research on urban forest is now extensive. Reports by The US Environment Protection Agency, The UK Forestry Commission, Australia’s Cooperative Research Centre on Water Sensitive Cities, have firmly established that modern cities cannot survive without a healthy population of trees. These reports confirm the physical, environmental, psychological and economic advantages that trees bestow.

Trees combat climate change by directly reducing carbon dioxide, the key greenhouse gas. According to Australia’s Chief Scientist, our trees store ten times more carbon per hectare than grasses. Trees also reduce the greenhouse effect by shading our homes and office buildings reducing the need for air conditioning.

The large amount of hard surfaces in cities results in the production of “Urban Heat Islands” (UHI) because hard surfaces absorb rather than reflect heat, causing the temperatures in urban areas to be higher than the surrounding countryside. According to Dr Andy Coutts, from the Cooperative Research Centre for Water Sensitive Cities at Monash University, said a heat map of Melbourne during a recent heatwave revealed that surface areas under tree canopies were 7 to 9 degrees cooler on average than under unshaded hard surfaces.

”Trees are nature’s air conditioners,” says Dr Coutts. ”It does cost money to maintain the urban forest, but the benefits provided by trees like urban cooling, energy savings, and stormwater runoff reduction help justify the investment in urban greening programs.”

Trees reduce air pollution. They absorb carbon dioxide and other dangerous gases and replenish the atmosphere with oxygen. Trees help to settle, trap and hold particle pollutants (dust, ash, pollen and smoke) that can damage human lungs. Particulates are trapped and filtered by leaves, stems and twigs, and washed to the ground by rainfall.

For most of us, the benefits that trees bring have little to do with the indisputable scientific evidence in favour of trees. Trees make our cities more liveable because they are beautiful. Trees make us feel better about where we live.. Cities with abundant tree cover are more attractive. Forested cities foster mental well-being among their inhabitants; patients in hospitals recover more quickly when they can see trees and other vegetation. People who live close to forested parks report a greater sense of connection to their neighbourhood than those who don’t.

Why must we keep trees in cities? Because we can’t live without them.

Therese Doyle

Greens Councillor, Ward 2

Newcastle City Council

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