Urban Trees are continuously exposed to several stress situations like air pollution, soil compaction, exhaust gases, damage of tree trunks, etc. For the responsible authorities it is important to anticipate these problems, as the consequences of possible accidents can be considerable (e.g. tree fall).EUROSENSE can provide a number of products that are important means for designing a correct policy for urban trees on short and long term.
Acquisition of images -The acquisition of aerial or satellite images is the basis of tree inventory, mapping and most of our products. The assessment of the physiological tree status is done with colour infrared (IR) images. In the IR spectrum of the light, vegetation reflects much more and can hence be better analysed than in the case of normal light spectrum.
Tree inventory - An inventory of the tree patrimony is the basis of a good tree management. Tree species identification, tree height, trunk circumference measurements and spatial localization of trees are primary needs for every Green City Service.
Tree crown diameter - 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.
Tree labelling - In the field, every tree can be labelled to assure the correct identification.
Tree status assessment - Mechanical Status: EUROSENSE assesses tree stability with the Visual Tree Assessment method. This consists in identifying internal mechanical defects using external signs (e.g. appearance of the trunk, fungal fruiting bodies,…).
Physiological status: unhealthy trees, although appearing healthy on the field, can already exhibit obvious illness symptoms (lower red colour levels) on the colour infrared images. Mostly, this bad physiological status will only be visible on the field several years later.
Data management - The integration of each tree into a GIS (Geographic Information System) database is essential. Within this GIS, the user can request, observe and add data during different stages of the tree management. By publishing the obtained data online, citizens can also visualize the results.
Analysis tools - Trees can be evaluated through time by making evolution maps: improvement or deterioration of the health status of trees can be visualized. Statistical analysis, like tree species, health status distribution, etc. can be very useful in reports. Tree policy and management plan - A clear tree policy can result in a detailed management plan indicating concrete measures for every tree.