Showing posts with label biophilia. Show all posts
Showing posts with label biophilia. Show all posts

Tuesday, January 1, 2019

What the economy really needs more of: trees

I think the first economist must have been named Horatio. He’s the one who had to be reminded there were more things in heaven and earth than dreamt of in his model.

I try to keep my horizons wide by regularly consulting my second-favourite website, The Conversation (with academics who know a lot of interesting things about a lot of topics), to which I’m indebted for most of what follows.

We’re meant to know all about photosynthesis, but did you realise it means that, “with a bit of sun, a tree uses the natural miracle of photosynthesis to combine a little water with carbon dioxide from the air to produce the building blocks for its own growth, as well as oxygen,” according to Associate Professor Cris Brack, of forest measurement and management at the Australian National University?

So, to oversimplify a little, we breathe in oxygen and breathe out carbon dioxide, whereas trees breathe in carbon dioxide and breathe out oxygen – making them useful things to have around when we have a problem with excess carbon emissions.

But trees do far more for us than help with our greenhouse problem. For a start, they cheer us up. Academics at the universities of Melbourne and Tasmania examined 2.2 million messages on Twitter and found that tweets made from parks contained more positive content - and less negativity - than tweets coming from built-up areas.

Why are people in parks likely to be happier? Because parks help them to recover from the stress and mental strain of living in cities, and provide a place to exercise, meet other people or attend special events.

The world is becoming more urbanised. There’s now more than half the world’s population living in cities. In Australia, two-thirds of us live in capital cities and nine out of 10 of us live in urban environments.

There are sound economic reasons why so many of us are piling into big cities, but it seems there are also health and social problems. According to the experts, cities are becoming the epicentres for chronic, non-communicable physical and mental health conditions.

But there’s growing recognition of the crucial role of urban green spaces in helping reduce these health problems. More than 40 years of research shows that experiences of nature are linked to a remarkable breadth of positive health outcomes, including improved physical health (such as reduced blood pressure and allergies, less death from cardio-vascular disease, and improved self-perceived general health), improved mental wellbeing (such as reduced stress and better restoration), greater social wellbeing and promotion of positive health behaviours (such as physical activity).

Our cities are getting hotter, more crowded and noisier, while climate change is bringing more heatwaves, according to environmental planners at Griffith University. The obvious answer is more air-conditioning, but this brings more carbon emissions, so a better answer is more infrastructure – “green infrastructure”, otherwise known as street trees, green roofs, vegetated surfaces and green walls. In reality, however, vegetation cover in cities is declining, not increasing.

Planting trees in parks, gardens or streets has many benefits, helping to cool cities, slowing stormwater run-off, filtering air pollution, providing habitat for some animals, making people happier and encouraging walking.

According to those environmental planners, shading from strategically placed street trees can lower surrounding temperatures by up to 6 degrees – or up to 20 degrees over roads. Green roofs and walls can naturally cool buildings, substantially lowering demand for air-conditioning.

By contrast, hard surfaces – including concrete, asphalt and stone – increase urban temperature by absorbing heat and radiating it back into the air.

But though scientists have much evidence that trees and other greenery improve our mood and health, they know less about the actual mechanisms by which this occurs. Japanese research, however, suggests that when we walk through bushland we breathe in three substances: beneficial bacteria, plant-derived essential oils and negatively-charged ions.

We live our lives surrounded by beneficial bacteria, breathing them in and sharing our bodies with them. Gut-dwelling bacteria break down the food we can’t digest and produce substances that benefit us physically and mentally.

Plants and the bacteria living on them produce essential oils that fight off harmful micro-organisms when we ingest them.

And despite the nonsense talked about negative-ion generating machines, there’s evidence that negative air ions may influence our mental outlook in beneficial ways.

This may sound very new and scientific to some (or pseudo-scientific to others) but, as Hugh Mackay observes in his latest book, Australia Reimagined, being connected to nature is a traditional source of relief from anxiety: gardening, bushwalking, strolling in a park, walking the dog, climbing a tree, swimming in the sea or sailing on it, picnicking in a tranquil and beautiful setting, playing games that take you outdoors and into a natural environment.

We know instinctively that “grass time” – running on it, rolling in it, throwing and catching a ball across it – is vital for the health and wellbeing of children. Particularly if they’ve been cooped up indoors, glued to a screen. But adults are no different, the wise man says.
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Wednesday, December 27, 2017

Why going to a park is better than going to the beach

My father was always disapproving of people who excused their failure to turn up to his Sunday meeting by saying they'd been "worshipping God in the great outdoors". But the older I get, and the more I read, the more I think it's not such a bad idea.

I'm much attracted by the American biologist Edward O. Wilson's hypothesis of biophilia, that humans have an innate tendency to seek connection to nature, for its calming effects.

While most people will be heading for the beach in the next few weeks, I usually head for a national park, to lift my quota of trees, bush, grass and anything else that's green.

This time, however, we're heading for a jungle – otherwise known as Manhattan – to do babysitting duty. Ideally, this means I'd be virtually living in Central Park, but that may be a bit too snowy.

My regular reading of the universities' blogsite, The Conversation, has garnered a fair bit of evidence for biophilia.

According to a survey conducted by the Australian Bureau of Statistics in 2007, each year one in five Australians experiences a mental disorder. Most common are anxiety disorders, such as panic attacks or obsessive-compulsive disorder.

Zoe Myers, an urban design specialist at the University of Western Australia, says research shows that city dwellers have a 20 per cent higher chance of suffering anxiety and an almost 40 per cent greater likelihood of developing depression.

Fortunately, research also shows that people in urban areas who live closest to the greatest green space are significantly less likely to suffer poor mental health.

Myers says more than 40 years of research shows that exposure to nature increases calm and rumination, decreases agitation and aggression, and improves concentration, memory and creative thought.

But it's not emptiness or quiet that has these good effects, she says. "Nature in its messy, wild, loud, diverse, animal-inhabited glory has most impact on restoring a stressed mind to a calm and alert state.

"This provides a more complete sense of 'escape' from the urban world, however brief."

Many studies have attested to the restorative effects of forests but, though holidays in national parks are nice, we need something closer to home.

Melanie Davern, of RMIT University, with colleagues from Melbourne University, say recent research on the benefits of urban greening has found, for instance, lower rates of anti-depressant prescriptions in neighbourhoods close to woodlands in Britain, happier people living in areas with more birdlife, and better health in areas with increased neighbourhood tree coverage in the United States.

Planting trees in parks, gardens or streets has many benefits: cooler cities, slower stormwater run-off, filtering of air pollution, habitat for some animals (such as birds, bats and bees), making people happier and providing shade that encourages more walking.

Professor Pierre Horwitz, of Edith Cowan University, is a great advocate for urban bushland – a bush park of native trees, a wetland, or any native vegetation characteristic of the local region.

"With its undisturbed soils and associated wildlife, urban bushland is more diverse than other types of green spaces in our cities, like parks. The more unfragmented the landscape, or unaltered the bushland, the more likely it will be to retain its biodiversity," Horwitz says.

"Exposure to biodiversity from the air, water, soils, vegetation, wildlife and landscape, and all the microbes associated with them ... enhances our immunity. This is thought to be key to the health benefits of nature."

Horwitz says we know that wealthier people tend to live in greener suburbs, and that wealthier people tend to be healthier. So is it wealth rather than nature that's doing the good work?

Fortunately, no. Many studies have controlled for wealth but still found direct health benefits from exposure to biodiversity.

The benefits go not just to individuals, but to the wider city. Forests and woodlands clean our urban air by removing particles and absorbing carbon dioxide. This reduces premature death, acute respiratory symptoms and asthma across the city.

As well, urban bushland improves city water. Wetlands and the vegetation around them clean water by filtering, reducing exposure to pollutants carried in groundwater or surface run-off.

And not forgetting that vegetation moderates extremes of temperature, providing shade when it's hot and less exposure when it's cold, thus reducing heat- or cold-related illnesses.

Trouble is, urban bushland shrinks as new suburbs are developed on the outskirts of our cities. Worse, bigger houses and more high-rise living is causing backyards to be shrinking, too, even though they contribute to our health and our kids' development.

Not to worry. There's a lot of urban roof space, and we're getting more rooftop gardens. Sara Wilkinson and Fiona Orr, of the University of Technology Sydney, studied the use of a rooftop garden at St Vincent's Hospital in Sydney as part of two "horticultural therapy" programs for people recovering from mental illness.

Among the many benefits participants identified were regular connection with others, developing friendships, experiencing enjoyment and restoration of health.

And if you don't have a spare rooftop, you can join the latest trend and install a vertical garden.

Sorry, I'm getting a bit over-excited here. I wonder if "green space" still counts as green when its covered in snow? Hope the apartment we're renting at least has some indoor plants.
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