More trees grow in the city than on the mountain

2003/10/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Botanika

To this conclusion they have come after an experiment in the US. The objective of this experiment was to know the relationship between the pollution of the cities and the growth of the trees, and for this they have changed the poplar Populus deltoides, very common in the USA, in the heart of New York and in the surroundings.

Surprisingly, the poplars planted in the city have grown more than the country ones. According to the researchers, their “fault” lies not in the composition of the earth, nor in the temperature, nor in the concentration of carbon dioxide, but in the ozone.

The ozone layer at the top of the atmosphere protects the earth's surface from solar ultraviolet rays, but when it is near the surface it becomes pollutant. This is because sunlight occurs by reacting with the gases emitted by cars and, among other things, prevents plant growth.

But ozone is very reactive and reacts in the city with other pollutants, so in the heart of cities there is hardly ozone. On the contrary, in the surrounding rural environment, ozone pollutes the air and prevents tree growth.