Improve tree health

The health and vitality of urban trees are of central importance to the stability of the urban ecosystem in terms of providing habitats for wildlife, mitigating heat stress, and thereby promoting well-being.

However, urban trees are increasingly facing challenges such as prolonged periods of heat and drought, lowering of the water table, sealed and compacted root zones, and pest infestations. Many of these factors are interrelated. In addition, monocultures along long stretches of streets and in neighborhoods where the same few tree species are consistently favored pose risks regarding the spread of plant diseases, reduced biodiversity, and thus their ecosystem services.

To enable a useful assessment of tree vitality and individual growth status—particularly during the early years of establishment—the use of vitality sensors (e.g., soil moisture sensors in combination with leaf area index sensors or multispectral sensors that measure photosynthetic activity) is one option. These sensors provide precise data that allow for continuous assessment of water supply, enabling its optimization before damage to the tree occurs (drought stress, root development). In addition, multispectral sensors could provide information on overall vitality. The use of drone imagery would also provide information on growth and canopy development. If there are indications of suboptimal conditions, nutrient levels—as well as the presence of pollutants or mechanical damage—could be determined through on-site inspections and sampling.

Overall, early detection would prevent domino effects in the spread of plant diseases. Tailoring maintenance measures to the trees’ actual needs can support the planning and management of maintenance work. Healthy tree growth prevents costly losses—which also result in significant losses of ecosystem services—that would otherwise have to be offset by replanting.

The vitality of urban trees plays an important role in many aspects of urban development and open-space planning. It promotes the climate resilience of urban areas and helps mitigate the negative effects of heat and other extreme weather events. In addition, it can support measures to promote biodiversity.