How much does a tree earn? Warsaw knows the answer

After conducting a pioneering scientific study in Poland

Following in the footsteps of other world metropolises, Warsaw decided to count how much money trees can earn by improving the air quality and the health of residents. The answer is an estimated 170 million PLN per year (around 37.5 million EUR). The figures are based on the first study of this type in Poland, summarised on the city website last week.

9 million trees work 24/7 to make the air in Warsaw cleaner

Together with a team of scientists from the Warsaw University of Life Sciences, the municipality of Warsaw conducted a detailed analysis of selected ecosystem “services” provided by trees in Wola district. The evaluation was based on detailed measurements of biophysical indicators, with the use of specialized software by experts from the research team.

Thus, the “services” provided by trees depend on their species and age and tell us things like: how much oxygen they produce per year, how much carbon dioxide from the atmosphere they absorb and how well they clean the air from various pollutants (such as nitrogen dioxide, sulphur dioxide and PM2.5 suspended dust).

The pilot study examined 1300 trees in the specified district and it was made clear that they contribute to removing about 440 kg of harmful substances in one year from the air. In addition, they produce over 50 tons of oxygen, and absorb and store 20 tons of carbon dioxide. Furthermore, the most important result of the trees’ work – air purification - amounted to about 25.5 thousand Polish zlotys in this group of trees.

As the city mayor Rafał Trzaskowski explained, it is difficult to precisely estimate the value of the services for all nine million trees growing in Warsaw, as they grow in different conditions, but the rough estimation points to at least PLN 170 million per year.

However, the contribution of the survey goes well beyond numbers. According to city officials, the cooperation with university experts allowed them to better value and protect the green areas. It has also given them insight on how to shape the policy of sustainable development in Warsaw.

This, according to Justyna Glusman, Director and coordinator for sustainable development and greenery, gives extremely useful knowledge for further actions in the field of climate change adaptation policy and green management.

Finally, Dr Marzena Suchocka, an expert from the Warsaw University of Life Sciences' research team brought attention to the benefits of greenery on physical and mental health, saying that there is a direct link between increased greenery and improved wellbeing. She further pointed out the fact that in Liverpool, for example, the prices of apartments close to parks are 40% higher. And now we know there is a good reason for that.