Tree health monitoring for greener cities

Published in Environment

The challenge

Trees give us oxygen, store carbon, and stabilise the soil, thus improving air quality and contributing to a healthier environment. Recent studies have shown that they can have a beneficial effect on acute respiratory symptoms. People living in a tree-filled area are less stressed and have healthier babies. And patients heal faster and have less pain after surgery if they have a tree to look out at through the window of the hospital room. Just to say that trees are extremely important!

However, trees in urban areas are continuously exposed to numerous stress situations, like air pollution, soil compaction, exhaust gases and physical damage to the tree trunks. Which not only has negative consequences for our health but might even cause damage or accidents (falling trees, broken branches, …)

Therefore, it is vital for responsible authorities to anticipate these problems. But without the proper tools and information, this is easier said than done.

The solution

Fortunately, these tools do exist. The basis of tree inventory and mapping is the acquisition of aerial or satellite images, while the physiological tree status is assessed with colour infrared (IR) images. Vegetation reflects much more in the IR spectrum of light and can hence be better analysed than in the normal light spectrum.

An inventory of the tree patrimony – tree species identification, tree height, trunk circumference measurements and the spatial localization of trees – is essential for good tree management. Based on semi-automatic aerial or satellite image analysis, the crown diameter of every tree can be calculated. The location, the extent of trees and their proximity to buildings can be visualised in a GIS (Geographic Information System) environment. And in the field, each tree can be labelled to assure the correct identification. Trees can even be evaluated through time by making evolution maps, visualizing the improvement or deterioration of the health status of trees.

All this enables the green city service to map the physiological status of every tree and to establish a well thought out tree policy for the years to come.

Data provider: Eurosense

Eurosense offers high-quality geographical information – certificated according to the ISO 9001: 2015 standard – derived from spaceborne and airborne remote sensing sources. The company can provide you with a whole range of satellite images from all over the world, whereas airborne surveys are performed with four company-owned airplanes (or with helicopters, for corridor mapping and more detailed surveys). Eurosense has sensors for aerial photography, laser altimetry, and thermography, enabling them to acquire data day and night, and is specialized in the production of value-added products, such as land use maps and flood models.