Trees and citizens: conflicts or mutual benefits?

Cities occupy only 2% of the world's land surface and are home to more than 60% of the world population; it is expected that this percentage will rise to 80% in 2020. It is clear that the urban environment is different from the natural one and it results in a reduction of the average life of trees in cities. The spread of the Green city is considered one of the main indices of civilization and livability of urban areas. However, there is a hostile attitude between citizens and trees: for example, trees represent obstacle to the car park, roots damage sidewalks, leaves will dirty streets, not to mention, for those who suffer, allergies caused by pollen during blossom. The relations between plants and citizens have a role in the development of our society, affecting areas of environmental, social and economic science. In an urban environment, people communicate with Green through formal and informal rules, management strategies and cultivation practices; validity or not of these institutions has an impact on the health of trees and their ability to deliver these benefits in terms of health and quality of life of society. It is important to participate in the choices of the public administration, in order to quantify and communicate to the citizens the economic value of environmental assets and functions, defined ecosystem services; even if the estimation is uncertain because of the absence of market value. Tools of planning and management of the Public Administration (in Italy they are called “Piano del Verde” and “Regolamento del Verde”) have not yet been adopted by all municipalities, therefore, even today, there is necessity to strongly confirm the importance of protecting the urban Green as a common good.