Health is the complete well-being of body, mind, society and environment and not simply the absence of disease. The state of health is achieved through hygiene, security, a good social pact and good environmental treatment. The presence of positive factors increases the possibility of health and the negative ones decrease it. Trees are positive factors within Environmental Health.
Cities are ecosystems in which humanity predominates with its presence, activities and constructions. In these ecosystems called cities, humanity controls biological diversity based on the knowledge of whether they are a factor of health or are attributed as a factor of disease or whether they develop the character of a plague. The trees are part of the Biological Diversity of the Ecosystem called city.
Thus, humanity determines which species can or cannot live in the city and the number of individuals of each species. In the ecosystem called city there are native plants and plants introduced by humanity. Sometimes arbitrariness predominates in the selection.
Trees are environmental factors that are present in city-type ecosystems so we will try to indicate whether vegetation is important as a health factor.
The great service of oxygen contributions to the atmosphere as an end product of photosynthesis, is the important health factor that is most recognized to the trees, with its massive presence make the city a factory of oxygen for the atmosphere, for life.
In our tropical climate, sunny days are present all year round and are a determining factor in the high local temperature. It is attributed in some scientific works, that hot seasons are temporarily associated to an increase of acute ischemic cardiopathy, that is, angina and myocardial infarction. Trees can help break this association.
Green chlorophyll has a characteristic that is beneficial in this respect, as it reflects the infrared rays close to the atmosphere, returns them upwards and does not progress towards the surface or any masses found there. The near-infrared rays are the cause of the heating of the surface and the trees cool down, because by subtracting zones or surface heated by the near-infrared rays.
It can be said that the presence of trees in a home, institutional or business community is in fact a health factor because it helps to control heat, lowering the temperature and making heat transfer flow from the hottest areas to their shaded spaces, which are cooler.
That is why in our environmental groups (Amigos del Bosque and NATURAZUL), we promote community forests.
The trees allow us to walk under their shade on the sidewalks during the day, decreasing the use of vehicles for transportation. This allows the reduction of sedentariness, decreases the expenditure on tickets with investment of that budget in other needs. It also reduces the active vehicle fleet with the generation of less gaseous waste (fumes), less noise and the contribution of heat from their engines.
In addition, the trees are a barrier to prevent these fumes, noise and dust generated by the movement of vehicles from entering homes, institutions and businesses.
Trees are not only barriers for vehicular pollutants, they are also a filter for wind flow. The content of our atmosphere is not only made up of gases from this terrestrial environment, it also contains gases from vehicle and business processes and from the burning of materials. In addition, the atmosphere contains dust, pollen, salts and particles of algae and lake and marine animals, bits of dead vegetables and land animals, and bits of household, institutional and business waste. All this material enters our homes, government and health care institutions, and company facilities where we work through the wind.
That is why having the forest at home, institutional, outpatient, hospital, school and business, ensures the filtering of the wind, with the advantage of less "dirt" to clean, less exposure to all those pollutants contained in the atmosphere and reduced risk of triggering an acute respiratory illness or the complication of chronic respiratory diseases (chronic bronchitis, bronchiectasis, asthma, pulmonary emphysema, pulmonary fibrosis). It is a real advantage to have plants in our areas of life.
It is worth pointing out that the brake pads of the vehicles have among their components substances that can generate cancer of the Pulmonary Pleura. When braking, particles are released from these pads, which are not significant for this risk because the quantities are very small. But if our home, our place of recreation, of development of exercise activities, of sport or our place of work, is just in front of a high flow of vehicles, with the use of the brake of all those cars and the effect of load (quantity arranged for a long time), it is constituted in a risk factor for pleural cancer. The protection is established with a vegetal containment that serves to elevate the air flows and serve the plants in addition to filters for that dust.
• Last but not least, we would like to highlight the psychological effect of the presence of trees. Humanity, before its evolution to a hominid, used trees within its lifestyle. The tree is unconsciously a security value.
The extraordinary scenic value of trees in particular and plants in general, gives us a sense of beauty when contemplating it, associated with the diversity of birds, reptiles and mammals, the opportunity for recreation and a capacity for relaxation for some people. There are schools of psychology that endorse arboriculture (hugging the tree), for the treatment of neurosis.
The Environmental Factors for Health and Therapeutics, especially plants as one of those factors, must be known and promoted from the family, the community, from the institutional and business environments. Environmental Health makes us happy. Trees are our health allies.