More and more cities are investing in greening to mitigate the effects of climate change. Trees play a crucial role in this: they provide cooling, biodiversity and a more pleasant living environment. At the same time, some tree species bring a less visible challenge: the pollen they spread can cause hay fever symptoms in many people. For a healthy and livable environment, it is therefore important to make informed choices when planting new trees. The new Tree Compass offers a valuable tool.

An article explaining how the Tree Compass was created was recently published in the Dutch Journal of Allergy, Asthma and Clinical Immunology. GoHot project member Letty de Weger and colleagues made an overview of the most common tree species in the Netherlands and the extent to which their pollen causes allergenic symptoms. They used international scientific literature, the amount of pollen the species in question produce annually in the Netherlands and data on sensitivity of Dutch patients to different tree pollen species.

This combination of knowledge led to a classification of tree species into five allergenicity classes. The result is a practical and accessible tool that helps both professionals - such as municipalities, landscape architects and green space managers - and individuals make informed choices. For example, the compass shows which species are highly allergenic and thus less suitable for high-traffic areas such as schoolyards, playgrounds or shopping areas. At the same time, it offers insight into trees that cause little or no complaints, but that could potentially produce more pollen in the future due to climate change.