PLEA Network

3 February 2016, The Conversation, Our cities need more trees, but that means being prepared to cut some down. Planting more trees in our cities is a no-brainer, isn’t it? The federal government certainly thinks so, having last month unveiled a plan to increase the amount of tree cover in Australia’s cities. Tall trees with luxuriant canopies provide a wide range of benefits to sweltering urbanites. They reduce the urban heat island effect, take up carbon dioxide from the air, reduce wind, muffle traffic noise, help to retain rainwater, attract wildlife, improve human health, and they look nice. To take an example, Canberra’s 400,000 trees – all planted in the past century or so – now deliver benefits worth up to A$15 million per year. But trees are living things and start their urban life as small plants. It may take 50 years or more to reach their mature size and full value. So to get quick benefits, trees are “over-planted”, with many small tree canopies adding together for a significant overall effect. But this eventually leads to competition between the trees, which reduces their value, and so trees are then periodically thinned out. Such thinning is often not appreciated. The pioneering urban forester Charles Weston, tasked with turning Canberra’s barren landscape into a site fit for the nation’s newly chosen capital, over-planted for quick effect. His successor Lindsay Pryor then thinned out the trees, to help maintain the benefits, for which he was widely criticised: Read More here