tag:theconversation.com,2011:/fr/topics/urban-vegetation-25656/articles
Urban vegetation – The Conversation
2019-09-10T20:06:38Z
tag:theconversation.com,2011:article/122710
2019-09-10T20:06:38Z
2019-09-10T20:06:38Z
Trees can add $50,000 value to a Sydney house, so you might want to put down that chainsaw
<figure><img src="https://images.theconversation.com/files/290807/original/file-20190903-175686-7m15gb.jpg?ixlib=rb-1.1.0&rect=696%2C303%2C4464%2C2768&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Allowing residents to remove trees within three metres of buildings or 'ancillary structures' could dramatically alter the green infrastructure of dense inner Sydney suburbs like Rozelle.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/aerial-view-iron-cove-bridge-rozelle-1278519220?src=-1-9">Tom Casey/Shutterstock</a></span></figcaption></figure><p>Sydney’s Inner West Council has a <a href="https://innerwest.infocouncil.biz/Open/2019/08/C_27082019_MIN_3702_WEB.htm">new policy</a> that it is <a href="https://www.smh.com.au/national/nsw/tree-massacre-inner-west-councillors-warning-after-ambush-20190828-p52lk7.html">reported</a> means “residents will no longer need to seek council approval to prune or remove trees within three metres of an existing home or structure”. Hold on, don’t reach for that chainsaw yet, because <a href="http://www.aecom.com/content/wp-content/uploads/2017/04/Green-Infrastructure-vital-step-brilliant-Australian-cities.pdf">research</a> shows good green infrastructure – trees, green roofs and walls – can add value to your home. </p>
<p>Green infrastructure offers significant, economic, social and environmental benefits. Urban greening is particularly important in dense urban areas like Sydney’s Inner West. Among its benefits, green infrastructure:</p>
<ul>
<li><a href="https://theconversation.com/how-urban-bushland-improves-our-health-and-why-planners-need-to-listen-72876">improves air quality</a></li>
<li>provides <a href="https://theconversation.com/many-people-feel-lonely-in-the-city-but-perhaps-third-places-can-help-with-that-92847">space for social interaction</a></li>
<li><a href="https://theconversation.com/more-than-just-drains-recreating-living-streams-through-the-suburbs-83345">manages stormwater</a></li>
<li><a href="https://theconversation.com/why-are-cities-warmer-than-the-countryside-53160">reduces the urban heat island effect</a></li>
<li>provides space for <a href="https://theconversation.com/three-ways-cities-can-help-feed-the-world-without-costing-the-earth-112186">urban food production</a></li>
<li><a href="https://theconversation.com/the-small-patch-of-bush-over-your-back-fence-might-be-key-to-a-species-survival-108672">improves biodiversity</a>. </li>
</ul>
<p>Some of these benefits accrue to owners/occupiers, whereas others provide wider societal benefits. </p>
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Read more:
<a href="https://theconversation.com/higher-density-cities-need-greening-to-stay-healthy-and-liveable-75840">Higher-density cities need greening to stay healthy and liveable</a>
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<p>A <a href="http://www.aecom.com/content/wp-content/uploads/2017/04/Green-Infrastructure-vital-step-brilliant-Australian-cities.pdf">2017 study</a> focusing on three Sydney suburbs found a 10% increase in street tree canopy could increase property values by A$50,000 on average. And the shading effect of trees can <a href="http://www.gallagherstudio.com.au/blacktown-cool-streets-pilot-project">reduce energy bills by up to A$800 a year in Sydney</a>. So retaining your green infrastructure – your trees, that is – can deliver direct financial gains. </p>
<p>On a larger scale, a <a href="https://opus.lib.uts.edu.au/bitstream/10453/121458/1/Ghosh_Yung-Full-paper-Ecocity-Summit-2017-Final.pdf">collaborative project</a> with Horticulture Innovation Australia Limited compared carbon and economic benefits from urban trees considering different landuses along sections of two roads in Sydney. Higher benefits were recorded for the Pacific Highway, with 106 trees per hectare and 58.6% residential land use, compared to Parramatta Road, with 70 trees per hectare and 15.8% residential. </p>
<p>For the Pacific Highway section, total carbon storage and the structural value of trees (the cost of replacing a tree with a similar tree) were estimated at A$1.64 million and A$640 million respectively. Trees were also valuable for carbon sequestration and removing air pollution. </p>
<p>Tree species, age, health and density, as well as land use, are key indicators for financial and wider ecosystem benefits. Specifically, urban trees in private yards in residential areas are vital in providing individual landowner and collective government/non-government benefits.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/290832/original/file-20190904-175710-thqcje.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/290832/original/file-20190904-175710-thqcje.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/290832/original/file-20190904-175710-thqcje.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=228&fit=crop&dpr=1 600w, https://images.theconversation.com/files/290832/original/file-20190904-175710-thqcje.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=228&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/290832/original/file-20190904-175710-thqcje.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=228&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/290832/original/file-20190904-175710-thqcje.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=287&fit=crop&dpr=1 754w, https://images.theconversation.com/files/290832/original/file-20190904-175710-thqcje.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=287&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/290832/original/file-20190904-175710-thqcje.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=287&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Take away the trees close to these houses in Marrickville, in Sydney’s Inner West, and how much would be left?</span>
<span class="attribution"><a class="source" href="https://en.m.wikipedia.org/wiki/Henson_Park">Graeme Bartlett/Wikipedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<h2>Challenges of growth</h2>
<p>As populations grow, cities increase density, with less green infrastructure. The loss of greenery affects the natural environment and both human and non-human well-being. </p>
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Read more:
<a href="https://theconversation.com/were-investing-heavily-in-urban-greening-so-how-are-our-cities-doing-83354">We're investing heavily in urban greening, so how are our cities doing?</a>
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<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/290809/original/file-20190904-175682-j6pcza.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/290809/original/file-20190904-175682-j6pcza.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/290809/original/file-20190904-175682-j6pcza.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=816&fit=crop&dpr=1 600w, https://images.theconversation.com/files/290809/original/file-20190904-175682-j6pcza.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=816&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/290809/original/file-20190904-175682-j6pcza.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=816&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/290809/original/file-20190904-175682-j6pcza.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1026&fit=crop&dpr=1 754w, https://images.theconversation.com/files/290809/original/file-20190904-175682-j6pcza.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1026&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/290809/original/file-20190904-175682-j6pcza.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1026&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Tree canopy cover across Greater Sydney plummets closer to the city centre.</span>
<span class="attribution"><a class="source" href="https://www.greater.sydney/metropolis-of-three-cities/sustainability/city-its-landscape/urban-tree-canopy-cover-increased">© State of New South Wales through the Greater Sydney Commission. Data: SPOT5 Woody Extent and Foliage Projective Cover (FPH) 5-10m, 2011, NSW Office of Environment and Heritage</a></span>
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<p>Trees and other green infrastructure reduce some impacts of urban density. However, policies, government incentives and national priorities can produce progress in urban greening or lead to setbacks. In the case of the Inner West Council, for instance, the inability to fund monitoring of changes in tree cover could lead to reductions at the very time when we <a href="https://www.greater.sydney/metropolis-of-three-cities/sustainability/city-its-landscape/urban-tree-canopy-cover-increased">need more canopy cover</a>. </p>
<p><a href="https://theconversation.com/if-planners-understand-its-cool-to-green-cities-whats-stopping-them-55753">Key concerns</a> include installation and maintenance costs of green infrastructure (trees, green roofs and walls) in property development, and tree root damage. Knowledge and skills are needed to maintain green infrastructure. As a result, developers often consider other options more feasible. </p>
<p>In the short and long term, multiple performance benefits and economic and environmental values are needed to establish the viability of green infrastructure. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/australian-cities-are-lagging-behind-in-greening-up-their-buildings-97088">Australian cities are lagging behind in greening up their buildings</a>
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<h2>Learning from Stockholm</h2>
<p>Stockholm shares many issues found in Australian cities. Stockholm houses over 20% of Sweden’s inhabitants, is increasing in density and redeveloping land to house a growing population. Aiming to be fossil-free by 2050, Stockholm acknowledges the built environment’s role in limiting climate change and its impacts.</p>
<p>In a research project we intend to use <a href="https://theconversation.com/au/topics/virtual-reality-5439">virtual reality</a> (VR) and <a href="https://www.healthdirect.gov.au/electroencephalogram-eeg">electroencephalogram</a> (EEG) technology to assess perceptions of green infrastructure and reactions to it in various spaces.</p>
<p>Our project combines VR with EEG hardware, which measures human reactions to stimuli, to learn how people perceive and value green infrastructure in residential development. </p>
<h2>Identifying all the value of green infrastructure</h2>
<p>The many benefits of green infrastructure are both tangible and non-tangible. Economic benefits include:</p>
<ul>
<li>those that directly benefit owners, occupants or investors – stormwater, increased property values and energy savings</li>
<li>other financial impacts – greenhouse gas savings, market-based savings and community benefits.</li>
</ul>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/if-planners-understand-its-cool-to-green-cities-whats-stopping-them-55753">If planners understand it's cool to green cities, what's stopping them?</a>
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<p>The various approaches to evaluating net value present a challenge in quantifying the value of green infrastructure. The most common – cost-benefit analysis, triple bottom line, life cycle assessment and life cycle costing – are all inadequate for evaluating trade-offs between economic and environmental performance. Conventional cost-benefit analysis is insufficient for investment analysis, as it doesn’t include environmental costs and benefits. </p>
<p>This is salient for green infrastructure, as owners/investors incur substantial direct costs, whereas various shareholders share the value. Perhaps, in recognition of the shared value, a range of subsidies could be adopted to compensate investors. Discounted rates anyone? </p>
<p>Recent efforts to evaluate the business case for green infrastructure include attempts to identify and quantify the creation of economic, environment and community/social value. However, an approach that includes a more comprehensive set of value drivers is needed to do this. This is the gap we aim to fill. </p>
<p>The results of experiments using VR and EEG technology and semi-structured interviews will provide a comprehensive understanding of green infrastructure. This will be correlated with capital and rental values to determine various degrees of willingness to pay. </p>
<p>With this knowledge, property developers in Sweden and Australia will be able to make a more informed and holistic business case for increasing green infrastructure for more liveable, healthy cities. </p>
<p>Maybe we can then persuade more people, including those in the Inner West, to hang onto their trees and leave the chainsaws in the garage.</p><img src="https://counter.theconversation.com/content/122710/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sara Wilkinson has received/receives funding from: City of Sydney, Horticulture Innovation Australia, City of Melbourne, RICS Reseach Trust, KtH Stockholm.
</span></em></p><p class="fine-print"><em><span> Agnieszka Zalejska-Jonsson has received funding from Kamprad Family Foundation to conduct research on the value of green infrastructure in developing sustainable cities.</span></em></p><p class="fine-print"><em><span>Sumita Ghosh received funding from Horticulture Innovation Australia and Shoalhaven City Council. </span></em></p>
Greater urban density is making it harder to preserve, let alone increase, tree cover. It’s vital, then, to demonstrate the full value of green infrastructure for healthy liveable cities.
Sara Wilkinson, Professor, School of the Built Environment, University of Technology Sydney
Agnieszka Zalejska-Jonsson, Researcher, Division of Building and Real Estate Economics, KTH Royal Institute of Technology
Sumita Ghosh, Associate Professor in Planning, School of the Built Environment, University of Technology Sydney
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/82185
2017-08-20T09:26:56Z
2017-08-20T09:26:56Z
Growing more plants and trees can cut down the heat in Nigerian cities
<figure><img src="https://images.theconversation.com/files/182436/original/file-20170817-28171-91a4q3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Plants and trees cool themselves and the surrounding environment like this building in Paris, France. </span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Nigeria is regarded as a hot country. Average maximum temperature <a href="http://www.climatestotravel.com/climate/nigeria">can reach 38°C</a> - one of the hottest in sub Saharan Africa. In the last few years extreme heat and intense heatwaves have become a common experience in both rural and urban areas, showing that the country is getting hotter. This year, the Nigerian Meteorological Agency has <a href="http://www.vanguardngr.com/2017/03/nigerians-likely-experience-danger-heat-stress-2017-nimet/">warned</a> of an “above danger heat stress”.</p>
<p>These experiences are in line with <a href="http://ar5-syr.ipcc.ch/">projections</a> that the mean temperature of the planet is increasing, and expected to go on doing so. In Nigeria, the average air temperature is expected to rise by between 0.2 and 2.5°C over the next five decades, according to the <a href="https://www.researchgate.net/publication/229019531_General_overview_of_climate_change_impacts_in_Nigeria">UN’s Intergovernmental Panel on Climate Change</a>.</p>
<p>These increases can’t be overlooked. The effect is already being felt in cities which have developed what is known as <a href="http://www.sciencedirect.com/science/article/pii/S2352938517300381">“heat islands”</a>. These are urban areas that have higher temperatures than surrounding rural areas due to the fact that natural landscapes have been replaced by paved surfaces and buildings. </p>
<p>Some <a href="http://www.mdpi.com/2225-1154/3/4/775/htm">predict</a> that Nigerian cities may become too hot to live in.</p>
<p>Practical solutions are needed. One approach that’s been shown to work elsewhere is urban greening. This involves introducing trees and plants in places such as parks and gardens, streets, on walls and on top of roofs. By constantly releasing moisture into the atmosphere through their leaves, plants and trees cool themselves and the surrounding environment. This helps to reduce heat. This principle is well known and has been implemented in many European and <a href="http://www.sciencedirect.com/science/article/pii/S0169204610001234">North American cities</a>. </p>
<p>We <a href="http://www.sciencedirect.com/science/article/pii/S2212095513000084">studied</a> the temperatures inside and around two typical buildings in Akure, Nigeria. One of the buildings had trees around it while the other had none. The study was carried out for six months and spread across the two seasons (rainy and dry). It showed that tree shading had an impact on thermal conditions in buildings and their surroundings. </p>
<p>This evidence, alongside other research, shows that plants and trees need to be grown in the country’s cities. And everyone must play a part - individuals, households, communities, cities and states. </p>
<h2>Reducing temperatures and energy saving</h2>
<p>Our study showed that air temperature was higher and stayed that way for longer inside the building without vegetation, with indoor–outdoor temperature reaching a peak of 5.4°C for the unshaded building and 2.4°C for the tree-shaded one. The outdoor area around the tree-shaded building was cooler than around the unshaded one, irrespective of the season.</p>
<p>But the impact of the trees went beyond just the temperature. The cooler temperatures meant that there was less demand for indoor cooling like air-conditioners. </p>
<p>Two <a href="http://www.sciencedirect.com/science/article/pii/S0378778814004708">separate studies</a> done in Nigeria <a href="https://link.springer.com/article/10.1007/s12053-016-9449-4">show</a> that greening buildings can reduce the use of air-conditioning, leading to annual savings of about 34,500 NGN (US$218) in Akure and 17,255 NGN (US$162) in Owerri. These cities are in two different regions of Nigeria yet the results were similar.</p>
<p>Other studies support our research findings. A difference in the average <a href="https://www.ajol.info/index.php/ejesm/article/view/82353">temperature of 7.5°C</a> between spaces with trees and those without was recorded in Enugu, a city in South East Nigeria. In Abuja, researchers <a href="http://www.sciencedirect.com/science/article/pii/S2352938517300381">found</a> that bare surfaces and built-up areas had higher land surface temperatures while green surfaces maintained lower land surface temperatures. </p>
<p>Vertical greening systems like green walls in Lagos was found to have around 0.5°C reduction in <a href="http://www.sciencedirect.com/science/article/pii/S1877705815020986">temperature</a>. </p>
<h2>What must be done</h2>
<p>State and local governments have the main responsibility of introducing policies that would lead to more greening in Nigeria’s cities. In the last ten years <a href="https://www.pmnewsnigeria.com/2013/12/03/parks-and-gardens-development-the-lagos-example/">some states</a> and the Federal Capital Territory have <a href="http://fig.net/resources/proceedings/fig_proceedings/fig2010/papers/ts09e/ts09e_jibril_4638.pdf">built urban parks</a>. But much more needs to be done to significantly increase the amount of vegetation and green spaces in the country’s cities. Urban tree planting projects should be promoted on streets and beyond. </p>
<p>There should be programmes to plant trees in neighbourhoods and to create vegetated play parks, community gardens and other forms of green open spaces. Plants should also be planted in road setbacks and spaces within dual carriage ways. Vacant lots and derelict buildings can also be purposefully vegetated.</p>
<p>There should also be a push for gardens to be created – for food as well as aesthetic reasons – inside houses, on the roof or on the walls. Densely packed built environment in cities make space a challenge. But this can be overcome through plant growing techniques that use up little or no space. Good examples of vertical greening systems are <a href="https://www.youtube.com/watch?v=pzwUDz5Bifc">available in Mexico City</a>. </p>
<p>These examples provide proof that vegetation at the household and community level can directly influence temperature in the neighbourhood. We believe urban greening is a task that can, and must, be done.</p><img src="https://counter.theconversation.com/content/82185/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Greening cities have a huge impact. The trees go beyond just lowering temperatures. They help decrease the demand for indoor cooling like air-conditioners saving money.
Olumuyiwa Adegun, Lecturer, Department of Architecture, Federal University of Technology, Akure
Tobi Eniolu Morakinyo, Postdoctoral fellow at the Institute of Future Cities, Chinese University of Hong Kong
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/80330
2017-07-19T20:01:43Z
2017-07-19T20:01:43Z
Farming the suburbs – why can’t we grow food wherever we want?
<figure><img src="https://images.theconversation.com/files/178539/original/file-20170717-3405-68r6ov.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Some local councils are more tolerant than others in allowing residents to grow food where they want.</span> <span class="attribution"><a class="source" href="http://www.dscribe.net.au/2017/05/30/growing-crops-on-your-nature-strip-feeding-off-the-kerbside/">dscribe</a></span></figcaption></figure><p>Food provides the <a href="https://theconversation.com/reconnecting-with-food-essential-for-our-health-14313">foundations for human flourishing</a> and the fabric of sustainability. It lies at the heart of conflict and diversity, yet presents opportunities for cultural acceptance and respect. It can define neighbourhoods, shape communities, and make places.</p>
<p>In parts of our cities, residents have <a href="http://www.dscribe.net.au/2017/05/30/growing-crops-on-your-nature-strip-feeding-off-the-kerbside/">embraced suburban agriculture</a> as a way to <a href="https://theconversation.com/do-kids-who-grow-kale-eat-kale-64724">improve access to healthier</a> and <a href="https://theconversation.com/re-designing-food-systems-25728">more sustainably produced food</a>. Farming our <a href="http://www.urbanfoodstreet.com/">street edges</a> and <a href="https://communitygarden.org.au/2010/04/09/verge-gardens/">verges</a>, <a href="http://www.couriermail.com.au/questnews/southeast/guerilla-gardeners-use-vacant-land-at-highgate-hill-without-permission-of-owners/news-story/1b43b04f9d35db390620b5964e1eb611">vacant land</a>, <a href="https://communitygarden.org.au/2011/07/10/guerilla/">parks</a>, <a href="https://theconversation.com/biophilic-urbanism-how-rooftop-gardening-soothes-souls-76789">rooftops</a> and <a href="https://theconversation.com/birds-bees-and-bugs-your-garden-is-an-ecosystem-and-it-needs-looking-after-65226">backyards</a> is a great way to encourage an <a href="https://theconversation.com/10-tips-for-eating-locally-and-cutting-the-energy-used-to-produce-your-food-67060">appreciation of locally grown food</a> and increase <a href="https://theconversation.com/nhmrcs-healthy-diet-is-also-good-for-the-environment-4717">consumption of fresh produce</a>. </p>
<p>Despite these benefits, regulations, as well as some cultural opposition, continue to constrain suburban agriculture. We can’t grow and market food wherever we like, even if it is the sustainable production of relatively healthy options.</p>
<p>While good planning will be key to a healthier, more sustainable food system, planning’s role in allocating land for different uses across the city also constrains suburban agriculture. </p>
<h2>Two steps towards healthier food systems</h2>
<p>Making our food systems <a href="https://theconversation.com/trimming-the-excess-how-cutting-down-on-junk-food-could-help-save-the-environment-65338">healthier</a> and <a href="https://theconversation.com/is-it-time-to-resurrect-the-wartime-grow-your-own-campaign-66337">more sustainable</a> requires a two-step approach. </p>
<ul>
<li><p>First, we need to fortify the parts of the system that enable access to healthy food options. </p></li>
<li><p>Second, we need to disempower elements that continuously expose us to unhealthy foods. </p></li>
</ul>
<p>Although food is a basic human need, the way we consume food in many countries, including Australia, is harmful to the environment and ourselves. Many of us don’t eat enough <a href="https://www.heartfoundation.org.au/about-us/what-we-do/heart-disease-in-australia/fruit-and-vegetable-consumption-statistics">fresh and unprocessed foods</a>. The foods we do eat are often produced and supplied in <a href="https://www.nature.com/news/one-third-of-our-greenhouse-gas-emissions-come-from-agriculture-1.11708">carbon-intensive</a> and <a href="https://theconversation.com/growing-food-in-the-post-truth-era-78256?sa=pg1&sq=food&sr=1">wasteful</a> ways. </p>
<p>Primarily through land-use zoning, town planners can help to shape sustainable and healthy food systems. For example, good planning can:</p>
<ul>
<li><p>protect peri-urban agricultural lands;</p></li>
<li><p>encourage farmers’ markets, roadside stalls and community gardens;</p></li>
<li><p>prevent the location of fast-food outlets near schools; and</p></li>
<li><p>even help regulate food advertising environments.</p></li>
</ul>
<h2>Why have land-use zones?</h2>
<p>Modern town planning <a href="https://www.britannica.com/topic/urban-planning/The-era-of-industrialization">originated in the 19th century</a> out of the need and ability to separate unhealthy, polluting uses from the places where people lived. </p>
<p>This was a direct response to the Industrial Revolution, which brought with it both an upscaling of the noisy, smelly and dirty uses to be avoided, and the emergence of new ways to travel relatively long distances away from these uses. </p>
<p>As a result, our urban areas are made up of a mosaic of what we call zones. Within each zone, certain uses are permitted and others are prohibited. If a piece of land is zoned as commercial, for example, that land can be used for a shop, but not for a house.</p>
<p>While this might seem logical to us today, to those living in <a href="https://books.google.com.au/books?id=12GtHXOw8QQC&pg=PA11&lpg=PA11&dq=living+among+factories+tanneries+Manchester&source=bl&ots=kUmo3KxFPP&sig=uvUI6TPBuicGAZnKp07ewTzPlew&hl=en&sa=X&ved=0ahUKEwiluKzY-JPVAhVHzLwKHQjVDSkQ6AEINjAC#v=onepage&q=living%20among%20factories%20tanneries%20Manchester&f=false">housing scattered among the factories and tanneries</a> of Manchester in the 1800s it would have been quite radical. </p>
<p>It is this function of planning that means we cannot grow food anywhere in the city. Instead, we have regulations that attempt to ensure related activities occur only in areas where such a use is compatible with the surrounding uses. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/178540/original/file-20170717-27512-1whx6kk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/178540/original/file-20170717-27512-1whx6kk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/178540/original/file-20170717-27512-1whx6kk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=922&fit=crop&dpr=1 600w, https://images.theconversation.com/files/178540/original/file-20170717-27512-1whx6kk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=922&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/178540/original/file-20170717-27512-1whx6kk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=922&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/178540/original/file-20170717-27512-1whx6kk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1159&fit=crop&dpr=1 754w, https://images.theconversation.com/files/178540/original/file-20170717-27512-1whx6kk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1159&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/178540/original/file-20170717-27512-1whx6kk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1159&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Where food gardens are next to roads these should not carry heavy traffic, which could be a source of contamination.</span>
<span class="attribution"><a class="source" href="https://communitygarden.org.au/2010/04/09/verge-gardens/">ACFCGN</a></span>
</figcaption>
</figure>
<p>Incompatibility might relate to safety. For example, in some cities it is <a href="https://www.communityrun.org/petitions/stop-blocking-a-community-garden-qld-dept-of-main-roads">prohibited</a> to locate a community garden on a main traffic-generating road due to concerns about contamination of produce. </p>
<p>It could also be related to amenity. For example, in some areas local produce cannot be sold on the <a href="http://www.ahc.sa.gov.au/ahc-council/Documents/Strategies%20Policies%20and%20Plans/New%20folder/Roadside%20Trading%20150310.pdf">roadside</a> due to concerns about creating additional traffic and parking. </p>
<p>These are two fairly obvious examples, but problems arise when definitions of what is safe and amenable differ within the community. Does a verge planted with an over-enthusiastic pumpkin vine detract from or enhance the visual appeal of the street? Should a locality embrace a roadside produce stall even if it means traffic is slowed and parking is less available? </p>
<h2>How do we resolve planning conflicts?</h2>
<p>Town planners attempt to grapple with these issues by developing new policies and regulations to respond to changing demands, or by assessing applications for food growing and distribution on a case-by-case basis. </p>
<p>In cities that are rapidly densifying, and in a cultural environment where growing one’s own produce is <a href="http://www.tai.org.au/sites/defualt/files/PB%2059%20Grow%20Your%20Own.pdf">enjoying a renaissance</a>, it’s not surprising some local authorities are <a href="http://www.abc.net.au/news/2017-05-31/urban-food-street-trees-culled-sunshine-coast/8576700">struggling to keep up</a>. </p>
<p>This struggle is ostensibly the result of local authorities failing to recognise and prioritise their role in supporting sustainable and healthy food systems. There are immense benefits – biophysical, economic and social – to be gained from local government giving priority to urban agriculture. </p>
<p>Yet a <a href="https://www.nswpcalipr.com.au/examples/csp-heal-baseline-report/">recent study</a> of the content of local community strategic plans across New South Wales found that only 10% of strategies mentioned anything about food systems as a community priority. In this sense, Australia is part of an <a href="https://theconversation.com/why-all-cities-should-have-a-department-of-food-39462">international trend</a>. </p>
<p>Surprisingly, the local authorities in New South Wales doing the most for better food systems were regional councils. These saw food security and the opportunities presented by local food production as urgent issues. There is obviously room for our metropolitan councils to catch up and capitalise on increased cultural interest in farming our suburbs.</p><img src="https://counter.theconversation.com/content/80330/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jennifer L. Kent does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Urban residents are increasingly keen to farm verges, parks, rooftops and backyards, but planning rules sometimes stand in the way.
Jennifer L. Kent, Research Fellow, University of Sydney
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/69631
2016-12-29T20:58:39Z
2016-12-29T20:58:39Z
Go native: why we need ‘wildlife allotments’ to bring species back to the ‘burbs
<figure><img src="https://images.theconversation.com/files/150944/original/image-20161220-9515-1mhf2m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Native plants don't need much space really.</span> <span class="attribution"><span class="source">Simon Pawley/Sustainable Outdoors</span>, <span class="license">Author provided</span></span></figcaption></figure><p>As urban <a href="http://www.un.org/en/development/desa/news/population/world-urbanization-prospects-2014.html">populations around the globe skyrocket</a> and the demand for housing grows, space is increasingly at a premium in cities. Unfortunately, despite some notable efforts to include green space in cities, native wildlife is not often a priority for urban planners, despite research showing the benefits it brings to both <a href="http://www.sciencedirect.com/science/article/pii/S0169204614002552">people</a> and <a href="http://link.springer.com/book/10.1007/978-3-642-58001-7">ecosystems</a>.</p>
<p>It may seem that bringing biodiversity back into cities would require large areas of land set aside for habitat restoration. But it is possible to use relatively small spaces such as transport corridors, verges and the edges of sporting grounds. Think of it as <a href="http://onlinelibrary.wiley.com/doi/10.1111/1365-2664.12280/abstract">“land sharing” rather than “land sparing”</a>“.</p>
<p>The idea of transforming public areas in cities into green space is not a new one. Allotment vegetable gardens, which have long been a staple of British suburban life, are <a href="https://www.ted.com/talks/pam_warhurst_how_we_can_eat_our_landscapes">enjoying a revival</a>, as are <a href="http://communitygarden.org.au/">community gardens in Australia</a>. </p>
<p>These gardens are obviously great for sustainable food production and community engagement. But we think similar efforts should be directed towards creating green spaces filled with native vegetation, so that local wildlife might thrive too.</p>
<h2>Benefits for biodiversity</h2>
<p>Cities can be hostile environments for wildlife, and although <a href="http://onlinelibrary.wiley.com/doi/10.1111/geb.12404/full">some rare species are still present in some cities</a>, the destruction of habitats and growth of built-up areas <a href="http://bioscience.oxfordjournals.org/content/52/10/883.full">has led to many localised extinctions</a>. Often, species are left clinging on in particular reserves or habitat remnants. "Green corridors” through the built environment can link these habitat fragments together and help <a href="http://www.sciencedirect.com/science/article/pii/S0006320711004009">stop urban species from being marooned in small patches</a> – and this is where native gardens can help.</p>
<p>Cities are often built in fertile areas on coasts, and because of their fertility are <a href="http://onlinelibrary.wiley.com/doi/10.1111/geb.12404/full">often home to large numbers of species</a>, which means that planting native vegetation in public spaces can potentially help a wide range of different species. </p>
<p>A <a href="http://www.sciencedirect.com/science/article/pii/S0006320715001895">study in Melbourne</a> found that native vegetation in urban green space is essential for conservation of native pollinators, as introduced plants only benefit introduced bees. But with the right habitat, even small mammals such as <a href="http://onlinelibrary.wiley.com/doi/10.1046/j.1442-9993.2002.t01-1-01185.x/full">bandicoots can survive in urban areas</a>.</p>
<h2>Benefits for people</h2>
<p>Native green space in cities can also be used to educate communities about their wildlife. Community gardens can be a very effective way to bring people together and create a <a href="http://www.tandfonline.com/doi/full/10.1080/13549839.2011.586025?src=recsys">sense of identity and cohesion within a community</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/149170/original/image-20161208-18049-1j65q6m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/149170/original/image-20161208-18049-1j65q6m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/149170/original/image-20161208-18049-1j65q6m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149170/original/image-20161208-18049-1j65q6m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149170/original/image-20161208-18049-1j65q6m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149170/original/image-20161208-18049-1j65q6m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149170/original/image-20161208-18049-1j65q6m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149170/original/image-20161208-18049-1j65q6m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Native landscaping in playgrounds.</span>
<span class="attribution"><span class="source">Simon Pawley, Sustainable Outdoors</span></span>
</figcaption>
</figure>
<p>Many people in cities have <a href="http://richardlouv.com/books/last-child/">little or no contact with nature</a>, and this “<a href="http://osupress.oregonstate.edu/sites/default/files/Pyle.ThunderTree.Excerpt.pdf">extinction of experience</a>” can make them feel <a href="http://onlinelibrary.wiley.com/doi/10.1002/fee.1225/abstract">apathetic about conservation</a>. Green space lets city dwellers connect with nature, and if these spaces contain native rather than introduced plants, they have the added benefit of familiarising people with their native flora, creating a stronger sense of cultural identity.</p>
<h2>Where to share</h2>
<p>There are many places in urban areas that can be tinkered with to encourage native species, with little or no disruption to their intended use. Picture the typical Australian park, for example: large expanses of grass and some isolated gum trees. Biodiverse systems are more complex, featuring tall trees, smaller ones, shrubs, herbs and grasses, which together <a href="http://www.sciencedirect.com/science/article/pii/S0169534709002468">create diverse habitat for a range of species</a>. So by building native garden beds around single trees, at the park’s edges, or within designated areas (even among playgrounds!), we can gain complex layers of habitats for our native animals without losing too much picnic space.</p>
<p>We think of verges as places to park our cars or wheelie bins, but these grass borders are another underused area where we could plant native gardens. This not only improves the aesthetics of the streetscape but also <a href="http://onlinelibrary.wiley.com/doi/10.1890/09-0582.1/abstract">reduces water use</a> and the need to mow.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/149171/original/image-20161208-18046-1la5sd9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/149171/original/image-20161208-18046-1la5sd9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/149171/original/image-20161208-18046-1la5sd9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149171/original/image-20161208-18046-1la5sd9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149171/original/image-20161208-18046-1la5sd9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149171/original/image-20161208-18046-1la5sd9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149171/original/image-20161208-18046-1la5sd9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149171/original/image-20161208-18046-1la5sd9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Verge gardens.</span>
<span class="attribution"><span class="source">Simon Pawley, Sustainable Outdoors</span></span>
</figcaption>
</figure>
<p>Australia is a sporting nation and our sports grounds are cherished features of the urban landscape, yet there are plenty of opportunities here for native vegetation. The average golf course, for instance, only uses two-thirds of its area for actual golf (unless you’re a very bad shot). The out-of-bounds areas nestled between the fairways offer plenty of space for native biodiversity. Likewise, the boundaries of sporting ovals are ideal locations for native vegetation borders. </p>
<p>Even infrastructure corridors such as train lines, electricity corridors, and the edges of highways have the potential to <a href="http://rsos.royalsocietypublishing.org/content/3/11/160525">contribute to the functioning of local ecosystems</a>.</p>
<h2>Making it happen</h2>
<p>As the existence of community gardens and Landcare groups shows, there is already a drive within local communities to make these ideas a reality. In fact, some groups of “<a href="http://www.tandfonline.com/doi/abs/10.1080/13549839.2012.716413">guerrilla gardeners</a>” are so passionate about urban greening that they dedicate their own time and resources towards creating green public space, <a href="http://usj.sagepub.com/content/early/2013/07/29/0042098013497410.abstract">often without permission</a>. </p>
<p>But urban gardening doesn’t need to be illegal. Many councils in Australia have policies that encourage the planting of native plants in private gardens, with some even offering <a href="http://www.victoriapark.wa.gov.au/our-town/news/adopt-verge-program">rebates for native landscaping projects</a>.</p>
<p>Ultimately we need to both share and spare urban landscapes. By conserving habitat fragments and planting native gardens to connect these patches, we can bring native plants and animals back into our cities.</p><img src="https://counter.theconversation.com/content/69631/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lizzy Lowe's Endeavour Postdoctoral Fellowship is funded by The Australian Government Department of Education and Training </span></em></p><p class="fine-print"><em><span>Margaret Stanley does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
It is possible to use small spaces such as transport corridors, verges and the edges of sporting grounds for native wildlife habitat restoration, helping to bring biodiversity back into cities.
Lizzy Lowe, Postdoctoral fellow, University of Auckland, Waipapa Taumata Rau
Margaret Stanley, Senior Lecturer in Ecology, University of Auckland, Waipapa Taumata Rau
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/55753
2016-03-09T02:11:15Z
2016-03-09T02:11:15Z
If planners understand it’s cool to green cities, what’s stopping them?
<figure><img src="https://images.theconversation.com/files/113825/original/image-20160304-9507-63ceu6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The shimmer of a heat mirage shows how a hard road surface increases urban temperatures by radiating heat into the air.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Hot_road_mirage.jpg">Wikimedia Commons/Brocken Inaglory</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Our cities are getting hotter, more crowded and noisier. Climate change is bringing <a href="https://theconversation.com/sydney-so-hot-right-now-whats-behind-the-citys-record-run-of-warm-weather-55756">more heatwaves</a>, placing <a href="https://theconversation.com/adapt-now-to-prevent-poor-health-from-climate-change-report-40958">pressure on human health</a>, urban amenity, productivity and <a href="https://theconversation.com/building-climate-resilience-in-cities-lessons-from-new-york-52363">infrastructure</a>. </p>
<p>Urban residents naturally want to stay cool. Air conditioning is the usual choice, but it can be expensive to run. Air conditioning also adds carbon pollution, creates noise and can make outdoor spaces hotter. </p>
<p>So what else can we do to manage increasing urban heat? And who has the ability to act? </p>
<p>Urban planners are increasingly involved in developing and delivering urban greening strategies. While it seems like a “no brainer” to green cities, <a href="http://www.sciencedirect.com/science/article/pii/S0169204615000419">our international research</a> shows that planners are not always comfortable with this idea.</p>
<p>However, <a href="https://www.asla.org/greeninfrastructure.aspx">green infrastructure</a> – including street trees, green roofs, vegetated surfaces and green walls – is emerging as a viable way to help cities adapt to increased heat. Uptake of these technologies is slowly increasing in many cities around the world.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/114028/original/image-20160307-30500-gr7yt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/114028/original/image-20160307-30500-gr7yt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=570&fit=crop&dpr=1 600w, https://images.theconversation.com/files/114028/original/image-20160307-30500-gr7yt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=570&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/114028/original/image-20160307-30500-gr7yt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=570&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/114028/original/image-20160307-30500-gr7yt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=716&fit=crop&dpr=1 754w, https://images.theconversation.com/files/114028/original/image-20160307-30500-gr7yt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=716&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/114028/original/image-20160307-30500-gr7yt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=716&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Green walls cooling a building in Singapore.</span>
<span class="attribution"><span class="source">Tony Matthews</span></span>
</figcaption>
</figure>
<p>The Australian government has recognised this trend. An <a href="http://www.environment.gov.au/minister/hunt/2016/mr20160212.html">agenda to green Australia’s cities</a> is now in place. Stated aims include managing climate change impacts, reducing urban heat, improving urban well-being and increasing environmental performance.</p>
<p>This urban greening agenda is part of the Clean Air and Urban Landscapes hub, under the <a href="http://www.environment.gov.au/system/files/pages/2f561690-b47e-4bf2-b028-d18739b3486f/files/nesp-research-priorities-2015.pdf">National Environmental Science Program</a>.</p>
<h2>Benefits of urban greening</h2>
<p>The broadening appeal of green infrastructure is helped by the fact it offers <a href="https://www.griffith.edu.au/__data/assets/pdf_file/0004/275107/urp-rp32-matthews-2011.pdf">multiple benefits</a>. </p>
<p>For example, shading from strategically placed street trees can lower surrounding temperatures by <a href="https://www.researchgate.net/publication/273764538_Residents%27_understanding_of_the_role_of_green_infrastructure_for_climate_change_adaptation_in_Hangzhou_China">up to 6°C, or up to 20°C over roads</a>. Green roofs and walls can naturally cool buildings, substantially lowering demand for air conditioning. Green infrastructure can also provide habitat for wildlife, recreational opportunities for people, better management of stormwater runoff and improved urban aesthetics.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/114029/original/image-20160307-30476-eemx0t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/114029/original/image-20160307-30476-eemx0t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=493&fit=crop&dpr=1 600w, https://images.theconversation.com/files/114029/original/image-20160307-30476-eemx0t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=493&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/114029/original/image-20160307-30476-eemx0t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=493&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/114029/original/image-20160307-30476-eemx0t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=619&fit=crop&dpr=1 754w, https://images.theconversation.com/files/114029/original/image-20160307-30476-eemx0t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=619&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/114029/original/image-20160307-30476-eemx0t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=619&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Street trees and green walls helping to reduce urban temperatures.</span>
<span class="attribution"><span class="source">Tony Matthews</span></span>
</figcaption>
</figure>
<p>Hard surfacing, including concrete, asphalt and stone, is common in cities. It <a href="https://theconversation.com/explainer-why-are-cities-warmer-than-the-countryside-53160">can increase urban temperatures</a> by absorbing heat and radiating it back into the air. Green infrastructure can minimise this difficulty as it better regulates ambient air temperatures. Foliage allows local cooling through evapotranspiration, where plants release water vapour into the surrounding atmosphere. </p>
<h2>Why planners are cautious</h2>
<p><a href="http://www.sciencedirect.com/science/article/pii/S0169204615000419">Our research</a> examined urban planners’ attitudes towards green infrastructure use in Australia, England and Ireland. We found that planners are broadly aware of green infrastructure as an urban intervention. They understand its use, application and capacity to provide multiple benefits, especially in terms of managing urban heat.</p>
<p>The planners we interviewed, while recognising the potential value of green infrastructure, strongly cautioned that delivering the technology can be an uncertain process. The biggest barrier cited was that planning departments are not experienced with green infrastructure. </p>
<p>Put simply, they tend to avoid it because it has not traditionally featured on planning agendas. Like any new planning endeavour, green infrastructure can create institutional, legal, economic, social and environmental challenges. </p>
<p>Some of the biophysical challenges associated with green infrastructure delivery are novel. Choosing appropriate forms of vegetation, for example, may be difficult. Decisions must be made based on prevailing climatic conditions, drainage capacity and species growth patterns. </p>
<p>Will root systems damage buildings or underground utility networks? Might trees topple during storms and damage houses? Are roofs strong enough to support a rooftop garden? Planners may not be able to answer these questions, which creates a need for external experts to advise them. </p>
<p>Our findings also highlight socio-political factors as barriers. These include governance concerns such as the political context in which planning decisions are made. </p>
<p>Management issues feature, too. Chief among these are government commitments to budget for green infrastructure delivery and management. </p>
<p>Planners are also wary of public involvement. They know that public sentiment about green infrastructure can be influenced by perceptions of modified access, changed use, or loss.</p>
<h2>What can be done?</h2>
<p>The urgency of providing urban green infrastructure increases as climate change makes our cities hotter. Our research suggests the principal task for planners is to overcome embedded practices and to accept green infrastructure as an emerging but permanent urban feature.</p>
<p>This will not be easy. For example, a decision to use a road easement for green infrastructure may require multiple meetings with other government departments, utility companies and residents. Planners will need to coordinate these, manage stakeholder expectations and ensure cost sharing where necessary. </p>
<p>Legal, economic, social and environmental issues will require innovative solutions.</p>
<p>Planners will increasingly be tasked to deliver green infrastructure in cities. They will need to be clear on its value and be prepared to lead its delivery and learn from new challenges and solutions encountered along the way.</p>
<p>Urban residents all over the world stand to benefit if planners can successfully meet this challenge, particularly as hotter temperatures threaten urban comfort and habitability.</p><img src="https://counter.theconversation.com/content/55753/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tony Matthews receives funding from the Australian Research Council for research which examines the nexus between urban planning and climate adaptation.</span></em></p><p class="fine-print"><em><span>Jason Byrne receives funding from the Australian Research Council and the Gold Coast City Council (for research related to this article). </span></em></p>
It seems like a ‘no brainer’ to use urban greening to help cities adapt to increasing heat, but the uptake of green infrastructure, such as trees and vegetated roofs, surfaces and walls, is slow. Why?
Tony Matthews, Lecturer in Urban & Environmental Planning, Griffith University
Jason Byrne, Associate Professor of Environmental Planning, Griffith University
Licensed as Creative Commons – attribution, no derivatives.