Digital trees help build the city’s resilience to ongoing climate change and save citizens’ lives
Cities around the world are recognizing trees as one of their assets. They implement programs to increase green canopy coverage and evaluate their values for the entire ecosystem. With hyperspectral photos, IoT systems, and computer methods, it is possible to calculate how much money a single urban tree can save. In Warsaw, it is estimated at around 4 EUR per tree. It doesn’t seem like much until you see the number on the scale of 9 million city trees.
During the Digital Roads to Sustainability event Justyna Glusman, the Head Co-Ordinator of the Sustainability in the city of Warsaw, presented the approach undertaken by the capital of Poland on the application of new technologies in the management of urban greenery.
‘We have started to think of trees and greenery as a system – Glusman said. We have taken the evidence-based approach, which means that we need to calculate what we have in the green asset portfolio and its condition to manage it. If you start thinking of something as an asset, you have to ask how much value this asset presents, as assets basically earn money’
To improve planning and decision-making, Warsaw city hall has commissioned the study of the whole city to create maps of greenery. The remote sensoring starts from airborne laser scanning. Afterward, the hyperspectral images and multispectral images were taken.
The Warsaw city hall has identified more than 7 million trees thanks to the high-resolution tree canopy map. It is estimated that the largest trees cover another 2 million. The mapping process allowed the city to discover the dominant tree species, which trees are in worse condition, and which parts of the city have the lowest green coverage.
It was the first step to the implementation of the tree management system in Warsaw. The system includes: tree rights charter, canopy map, an app for gardeners, inventory of greenery, public information service, risk assessment, and valuation of ecosystem services.
Trees save lives and earn money
Urban greenspace has several environmental, social, and human health benefits. The lack of precise canopy estimates may hinder the quantification of these benefits. It has been proven that greenery in the city improves mental and physical health.
More than 3,000 Warsaw citizens die prematurely due to poor air quality. The Warsaw Institute for Life Sciences has calculated how much of the harmful substances the trees have removed from the air and how much oxygen they have produced.
The sample of 1336 trees in Warsaw has produced a value of more than 25,000 PLN (5,000 EUR). As there are around 9 million trees in the whole city, they deliver a value of more than 170 million PLN (36,5 million EUR) annually.
Creating digital twins of urban trees also has the added value of increasing the citizens’ awareness and engagement.
‘It is a scalable project. I believe it is extremely important because it shows in numbers, which is the benefit from greenery – Glusman concluded. – It’s very easy to translate to the citizens and convince them that this is the same value as the value of great infrastructure or architecture’.