trees hold the key

Now that we are entering the cooler months we have an opportunity to consider how our gardens and city will perform next summer and into the future under the sweltering temperatures which are being forecast. For many people, the solution is to put in air conditioning and in many instances this may be the only option left for them if their garden is too small to plant a tree. Others may choose to put up a shade structure, but this will only increase temperatures even further as all hard surfaces reflect heat back into the atmosphere and add to the heat island effect we are now experiencing in all cities around the world – even here in bushy Canberra. Aside from the beautiful colours, textures and habitats trees offer, they also keep temperature down around them and if there are enough of them in your neighbourhood (urban forest), then the temperature will be more comfortable than if there were few or none. In Canberra this last summer, suburbs with few trees were identified by ANU researchers as having up to a 7 degree difference in temperature than those suburbs with a good canopy cover of deciduous street and garden trees. ANU academic Liz Hanna said the 22-day study of 21 suburbs - which found consistent higher temperatures in outer areas compared to inner suburbs on either side of Lake Burley Griffin - confirmed international studies which linked temperature variation to urban design and foliage. ''Green spaces and foliage cool the environment and lessen the health risk, especially on these very hot days,'' Dr Hanna said. ''The striking difference in Canberra is likely to be based on the thick canopy of mature, shady, deciduous street trees.'' The unpublished data was part of background research done for an upcoming study on working in the heat in Australia to be completed by ANU's National Centre for Epidemiology and Population Health. Dr Hanna, the director of the Working in the Heat project, said the temperature findings highlighted the need for larger front and backyards. Read more:

http://www.canberratimes.com.au/act-news/trees-releaf-me--no-canopy-means-hotter-suburbs-20140115-30vka.html#ixzz2zksS3ahY