Green for hope
Trees carry out an important hydrogeological function: the leaves protect the soil from erosion caused by rain and the roots hold the soil preventing landslides and landfalls. Trees also carry out a fundamental ecological function: around the roots microfauna develop in the ground, the substances released by the plants fertilize the soil, and the trees provide a habitat for many other plants and animals. Furthermore trees have an important function in the landscape, as they make the view more beautiful. In the cities, the presence of green areas adds value to our houses, besides making the place where we live more pleasant. Scientists believe that someone looking at an urban landscape with many trees will have a slower heart-beat, his/her blood pressure will decrease and his/her brain activity will be more relaxed than a subject looking at a view without any plants. Furthermore, convalescent subjects show a more rapid healing capacity in the presence of green areas.
It has been noted that in the cities the houses that lie in the shade of the trees have indoor temperatures that are 2-3°C less than those in the sun. Recent studies have shown that if the green surface area in cities like Rome and Milan were to increase 10%, the temperature of the air would drop about 2°C with a consequent saving of energy of about 8-11%, to cool the houses.