During periods of severe summer heat, trees and other plants need special care. The Parks and Gardens Service (SEVE) has adopted a strategy to meet this challenge.
Most trees are perfectly capable of surviving a prolonged heatwave, while nevertheless suffering serious damage from successive droughts such as those we have experienced over the past decade. The Parks and Gardens Service of the City of Geneva (SEVE) has developed a prevention, care and adaptation strategy in response to this problem.
The aim is to enable the parks and their plants to survive recurrent heatwaves without wasting water, as it is impossible, for example, to water all 40,000 of the City’s trees.
Savings begin with prevention and a choice of tree species planted today capable of withstanding the heatwaves of tomorrow. Evergreen oaks, European nettle trees, hop hornbeams, Japanese pagoda trees, plane trees and other cedar trees common to southern Europe can successfully withstand the heat and many such trees have been planted in Geneva over the past decade.
For young, sensitive and outstanding trees, the Parks and Gardens Service implements the following techniques:
- mulch or other (non-composted) mixtures of shredded wood residue is spread around the foot of the trees. These “covers” protect the roots, foster soil life, improve biodiversity and are more effective at capturing water by retaining moisture in the soil;
- sensors placed on certain trees calculate moisture levels in the soil in real time so that watering can be adapted with great precision according to the real needs of the plants. As well as saving water and reducing watering rounds, these sensors collect valuable information.
For a number of years, the SEVE has also been combating urban heat islands through a range of tangible measures:
- black, tarmac paths attract heat. Some paths in the parks have been replaced by permeable clay-limestone surfaces, as is the case in les Bastions and William Rappard. These surfaces allow rainwater to irrigate the soil and trees directly;
- flowers and shrubs have been planted on traffic islands at road junctions such as those in la Servette and on Boulevard Helvétique, making them both cooler and more attractive while fostering biodiversity;
- the tarmac on Place Isaac Mercier and Place des Charmilles has been largely replaced by grass.
All these actions make their own contribution to lowering the temperature within the city.
Article modifié le 21.07.2022 à 11:44