While Geneva’s tree population has suffered significantly from the heat wave, prolonged periods of drought, and severe weather in recent months, teams from the Parks and Recreation Department (SEVE) are hard at work planting nearly 600 trees by spring 2023. Studies are also being conducted on the health of the trees and the conversion of parking spaces into planting areas.
Nearly 600 trees will be planted throughout the municipality by the Parks and Recreation Department (SEVE) between November 2022 and April 2023 to fulfill the commitment to triple the number of trees planted compared to the number felled. The SEVE has selected varieties resistant to water shortages and long periods of intense heat—hickory trees, Indian lilacs, Japanese pagoda trees, holm oaks, hop hornbeams, Mediterranean pines, box-leaved maples, and other fruit trees. Several large trees will be planted in Saint-Georges and Bertrand Park. An orchard will be created in Trembley Park, while the embankment at Place Sturm (on the Ferdinand Hodler Street side) will be planted with 80 young trees (saplings), 50 shrubs, and 500 perennials.
Supporting development and improving conditions
The large-scale tree-planting campaigns of the past two years (more than 1,500 new trees within the municipal area) require significant ongoing care, demanding additional human and material resources. The trees must be watered for at least three years before they become sufficiently resilient and self-sustaining. The long periods of summer heat waves and drought have had a severe impact on these young trees. SEVE teams have had to reorganize to provide additional watering. Trees along streets are the ones suffering the most. Lack of depth and space, poor soil fertility, and significant urban constraints are all challenges that compound those posed by climate change. These factors underscore the critical need to create better conditions so that young trees can thrive.
Preserving existing heritage
In addition to the tree-planting projects, SEVE is paying particular attention to the preservation of existing trees. Targeted studies are being conducted on the trees and soil in the Parc des Bastions and the Jardin Anglais, two highly frequented sites that host a large number of events. The trunks, crowns, branches, and bases of nearly 600 trees are being examined by an independent expert. Soil analyses will complement this study early next year, following the winter events currently underway on-site, to better understand the environment in which the trees thrive. Soil compaction and sealing are highly detrimental to the trees’ healthy development and survival. It is therefore essential to consider the tree heritage in close relation to the soils in which they grow. Similarly, any injury serves as an entry point for pathogens that can weaken the tree. The results of these studies will inform a strategy for managing the sites in a more respectful manner.
Examine the potential for planting in the least shaded neighborhoods
Finally, with the aim of increasing the areas available for tree planting, SEVE is conducting a pilot study on the potential for converting parking spaces in the Pâquis and La Jonction neighborhoods, as well as on the potential offered by city-owned private plots. “We must now prioritize action in neighborhoods and break up heat islands where they exist. What the public is asking for is no longer necessarily grand architectural gestures, but concrete actions that don’t take years to implement,” notes Alfonso Gomez, city council member in charge of the environment. The goal is to create planting pits that are large enough and continuous to allow roots to develop and thus enable trees to thrive sustainably. The first plantings as part of this project are expected to take place in the fall of 2023.