Community

The Need For Green

Tree Canopy Cover

Green infrastructure are important assets. Our parks, rivers, beaches, playgrounds, wetlands, conservation reserves, represent but a few of our green assets that are integral to the life and character of the city.

With government planning policies in more recent years having shifted the direction of future population and housing growth away from the city fringes, instead towards the densification of the city, we are already seeing the effects with somewhat of a renaissance of the city centre.

With more people choosing to live in and around the city centre, for the amazing amenity on offer, there has also been a resultant shift in mindset (mowing lawns each weekend? / or / efficient use of resources?). Many residents have responded with infill development and / or unit or apartment living

The resultant densification of the city is however, raising a few issues, one of these being the reduction in tree canopy cover. This issue has come about due to a large extent, the subdivision and development of “the old backyard” to be turned into new dwellings.

Doubleview 2012

*Courtesy:City of Stirling Urban Forest Overview

Doubleview 2017

There are a number of other reasons for tree canopy cover loss. Some of these include the installation of swimming pools, poor tree selection ie/ the gum tree that just got way too big for the backyard/courtyard, the wrong tree for the climate ie/ temperate or cool climate trees planted in warm climates or even because sometimes people just get fed up with the mess from all the leaves that just keep on falling – year round!

As a way to step up and do something about increasing tree canopy cover, work has been done by Federal, State and Local Government to implement policy and commitment in this space such as with the use of Canopy Cover Targets / Urban Forest policy. Other fantastic initiatives or resources such as with the introduction of “Tree Selector” tools, can help residents in deciding the “most appropriate” tree for their situation. Some Local Governments are even giving away free trees! (City of Stirling – Apr 2018)

Most of us would have come across a newspaper or magazine article, describing how the old leafy suburbs with avenues of well-established street trees, are highly sought after places. 

The literature often extends to write about the “added value” that the street trees in these suburbs offer, with some articles even offering analysis into the dollars and cents that the street trees can add to the value of a property.  So you’ve probably heard enough on this!

kings park elegrand
Kings Park

Sense of Place / Identity / Image

There is so much appeal taking a drive through a lush, leafy suburb. Many of us will identify that “special place” whether it’s because of that magical tree lined drive with its shady canopy, or it might be because of a unique, standalone “significant” tree that in addition to its aesthetic value, also acts as a landmark for the area. Old, majestic trees can also be an important link with the past.

Interestingly, psychological studies have found that a landscape can impact on how a person feels. 

Well treed neighbourhoods have the ability to have a calming effect (think of a forest and how this makes you feel). With this in mind, architects have for ages designed buildings and spaces to include green infrastructure, so much so that they are even designing inner city high-rise buildings to include roof-top gardens and/or vertical walls, so that its residents have “green value” whilst living in a concrete jungle.

 

Melbourne - One of many Green Wall initiatives

Reduced Energy Use

Want to save money? There are also economic benefits to be had with smart tree selection. The heat load on buildings, particularly those being baked in full summer sun can put a huge strain on the liveability within a building, so much so that air-conditioning units often have to run continuously, day and night. Trees have the ability to cool buildings by directly shading the building (in the same way most of us know how much nicer it feels to be underneath the shade of a tree, on a warm summer’s day). Smart tree planting may also cut down the force of the wind, thereby lessening the cold draughts and thereby lessening the need for additional warmth.

Health and Wellbeing   

Studies have also shown that natural green surrounds have the ability to reduce mental stress and irritability, along with improving the ability to concentrate. These studies have also found that greenery and scattered trees, or lush environments, have for millions of years of evolution been associated as a haven for food and water sources.  We have a predisposition to want to be in those places!  

Other direct health benefits include cleaner air. Trees absorb carbon dioxide (CO2) and release oxygen (O2). Trees also have an ability to reduce air pollution by intercepting and filtering harmful gases and airborne particle pollution, such as car fumes.

Trees also protect people from harmful UV radiation. Temperature and humidity also directly affects human health and wellbeing. Heat related health issues arise when the human body is subjected to heat stress.

Street trees also provide other valuable health / social benefits. Pedestrian footpaths are more comfortable to use when they’re shaded, such as for walking to school, shops, etc. Take a look at any Town Planning policy in most places around the world and you’ll find reference to walkability ie/Liveable Neighbourhood’s – it’s all about getting out and about your neighbourhood, by foot and not car. Meeting neighbours and or seeing new things in your neighbourhood, taking the dog for walks. 

“These are but a few additional health and social benefits of shady footpaths that are pleasant and comfortable when used.”

Hyde Park

Urban Heat Island

With the densification of the city and reduction in tree canopy cover, the resultant increase in “hard surfaces” ie/ paved surfaces, buildings, etc means that these impermeable surfaces absorb much more solar energy, resulting in an increase in the air temperature. So on a hot summer’s day, the temperature in the city is greater than the surrounding city fringe/rural areas as these surfaces have absorbed the heat and take longer to cool down after the sun has set. For this reason there is a direct benefit in having an urban canopy where shade limits the amount of sun hitting these hard surfaces.

Habitat and Biodiversity

Supporting a healthy canopy cover in the city will provide the opportunity to maintain and even enhance biodiversity in the city. Planning / Environmental agencies have been busy in recent times, working on projects that have mapped green corridors, important in maintaining ecological green corridors/links around the city. At a local level, Local Councils have also been very busy in working through ways to enhance the “Urban Forest” which will see an increase to canopy cover. This will provide the network to sustain wildlife corridors for local species for the longer term.

Red-tail-Cockatoo-web
Red tail-black cockatoo (Image taken Yokine Reserve)

Urban Water Management

Trees have the ability to intercept rainfall and consequently slow stormwater thereby having the overall effect of reducing the impact of flooding and erosion. Trees also act as a bio-filter by removing nutrients and sediments from the stormwater before it enters the groundwater and then into our river systems.

These are but a few of the important reasons for increasing tree canopy cover in our cities. The work being done by Local Council in developing Urban Forest policies together with its street tree programs will deliver increased canopy cover in the years to come. Please check with your Local Council about any Street Tree Policy and or help with a Tree Selection Tool.

P.S. Now is a great time to start getting your soil ready with compost and manure, in time for planting your select tree in the cooler months.

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