Many of us live in the city, either in high rise apartments or in houses in the suburbs. The environment can sometimes seem like a distant thing, perhaps a national park or a place far from the city. Even if there are few trees and shrubs in your neighbourhood, this ‘urban forest’ is an important part of the environment and it brings great benefits to us and others alike. The value of the collection of trees, shrubs and vegetated areas in public and private land includes:
Cooling the City
Trees can cool a city by as much as 5 degrees celcius by shading heat-absorbing concrete and bitumen, transpiring water from their leaves which is evaporated and provides a cooling effect, and reducing the demand for air-conditioning (which make air cooler inside but pumps out hot air outside). A cooler urban area encourages people to walk or ride bicycles and to enjoy the outdoors, rather than driving or staying inside with the air-conditioning on.
Improving Air and Water Quality
Trees absorb harmful gases and pollutants, like car exhaust fumes, and in return pump out essential oxygen. They also absorb carbon dioxide, which is ‘locked up’ in their physical structure, thus reducing CO2 emissions and its contribution to global warming.
They also help improve water quality by reducing the speed of water run-off into catchments by absorbing water through their roots, the rain falling on leaves and branches slows water penetrating the soil and so provides a more steady distribution of rain, they absorb and filter many nutrients and they reduce erosion by supporting the soil with their roots.
Improving the Ambience
Trees help reduce the glare from strong sun on buildings and roads, they soften the look of the urban landscape, they reduce the transference of noises and provide their own soft sounds from wind blowing through leaves and animals living in them. Studies have shown that people are less stressed when seeing or passing by vegetated environments, patients with views of nature recover from their illnesses quicker, and suburbs with more trees and vegetation have lower crime rates! The value of properties, whether to buy or rent, private or commercial, all increase with large trees on the grounds.
Trees and shrubs provide important habitat for many species. Shelter and food are not the only things. Branches and canopies provide aerial transport routes for possums and other animals and insects.