When we recommend planting a line of trees based on a microclimatic simulation in order to improve the thermal comfort of pedestrians, we consider the tree a bit like a large umbrella that pumps water and transpires.
Except that we immediately see the limits of this type of reasoning: it amounts to using the tree as a piece of furniture, which is still very reductive and even counterproductive.
First of all, a tree is a living being with a life cycle and a time of its own that has nothing to do with the time of human beings.
When we model the shade of adult trees in a digital model, we project a hypothetical future state, because everything will depend on the health and growth of the trees.
Ideally, a future state without trees should also be simulated in the event that they have not been able to fully develop (parasites, water stress, compacted soil, etc.).
Taking into account the growth and health of trees in a context of adaptation to climate change completely transforms its use.
But trees provide much more than shade in summer, a refuge for biodiversity and an improvement in the mental health of city dwellers.
When autumn comes, they completely transform the urban and rural landscape as their leaves become loaded with ochre dyes and tannins before falling.
The image shows a 33-meter-high Ginkgo biloba, over 800 years old and located in the city of Wonju in South Korea.
In addition to being a slow-growing species remarkably adapted to climate change (and especially air pollution), the Ginkgo displays incredible golden foliage in autumn.
Deciduous trees and shrubs remind us of the cycle of the seasons and warn us to prepare for winter.
I don't know of any piece of furniture that can mark the seasons.
When will we change our perspective on trees?
Source: V. Mure, J. Jullien
Image: lands.capearchitect via @Rainmaker1973 on X (Twitter)