If you think that trees, parks and gardens in the city are just street furniture, you are out of the way. A list to scroll through the benefits of their presence in built-up areas: from the fight against climate change to the pursuit of happiness

What is good for Gaia is also good for us humans. After the declaration of the G20 Summit - to plant 1 trillion trees by 2030 to reduce the impacts of global warming - there is a clear need to increase natural capital.

Many cities have now developed nature based strategic plans to increase their resilience. Milan, for example, with Forestami aims to create innovative and sustainable urban ecosystems in which plant nature and city act as a single organism .

Not surprisingly, Stefano Boeri, president of the Scientific Committee of Forestami, argues that "the real challenge today is linked to Urban Forestry: the woods around the cities, and continuous systems of important trees inside them, clean the air by absorbing fine dust, shade public areas avoiding excessive heating, reduce CO2. But not only: trees improve the quality of life and public health, a simple and practical contribution to the care of the planet and to put a stop to the risks of a future of inequality".

They produce oxygen

Maybe it's worth remembering and not thinking that concrete, wi-fi, parking are the natural elements of our lives. Trees are the reason why the Earth has become breathable and habitable. In a single season, an adult tree produces the amount of oxygen needed by 10 people. This is even more relevant in densely populated and polluted areas, where average oxygen levels are expected to drop by around 6%.

Clean the air

"Every year, between 3 and 4 million people die from air pollution and its permanent impacts on human health" explains Robert Mcdonald, lead scientist for The Nature Conservancy in a article published by the C40 cities network . "Trees are a cost-effective solution as a pollution barrier and air filter". U n adult tree in urban environment can incorporate an amount of carbon equal to 10-20 kg of CO 2 every year .

For Stefano Boeri "We need a real revolution: bringing forests to cities means limiting CO2 production right where a large part of it is produced, so that the CO2 is exploited as fertilizer and transformed into oxygen; means offering a concrete contribution to the slowdown of global warming and in favor of increasing biodiversity".

Water control

If cities are the kingdom of water-repellent materials such as concrete, trees are essential in absorbing excess water. The foliage has the ability to intercept up to 15% of rainfall and the greater infiltration of non-waterproofed soils helps to slow down and reduce the flow of rainwater. A planting inspired, for example, by the Oasian system studied by urban planner Pietro Laureano could help us in designing autocatalytic and anti-waste systems.

Read also: Piero Lauretano: let's learn from oases

More trees and less air conditioning

With rising temperatures it is essential for cities to have natural systems to reduce heat. Thanks to their transpiration, trees can reduce the air temperature from 2° to 8° C, helping to regulate the microclimate.

Thinking of the city as a space for all forms of living

Urban planting creates green corridors and allows the circulation and survival of insects and animals. The vision of the city as a habitat, in addition to not creating fractures between ecosystems, helps to get out of anthropocentric egocentrisms and open the mind to diversity and variety.

Mental health and well-being

Spending time among the trees is a fundamental resource for a happy existence. The certainty about the key role of greenery for care owes much to the studies of Roger Ulrich, pioneer of research on healing gardens: nature improves physical and mental health by increasing energy levels and ability to concentrate, decreasing blood pressure and stress. For Elena Lucini , one of the founders of the Italian Association of Environmental Psychology and Architectural, "nature is therapeutic, a resource that educates us to wait and helps us to recover the sense of our own biological time". 

Share green spaces to create communities

Social cohesion and trees are closely linked. Access to green spaces contributes to increasing the sense of community, reducing isolation and marginalization, and promoting new lifestyles. Think of the Gangsta Garden project by Ron Finley, where the perception of public space in a suburban area of Los Angeles was created thanks to earthen seeds and caissons.

Memory and imagination

Trees are long-lived beings, they survive us and memorize the history of the planet. Perhaps we should look at these incredible natural works with the respect of one who turns to an ancestor. Perhaps we should entrust our memories to them so that they can be part of a collective history. Perhaps, if we were inspired a little more by nature, our capacity for imagination would acquire a new dimension. And, if it is true what Emanuele Coccia writes "imagining is always becoming what one imagines", if we look at the trees, we are on a good path.

Read also: Emanuele Coccia: a home can make us happy