We were present at the technical morning organized by one of our distributors, Hortibreiz, alongside 25 participants, mainly local authorities, landscapers and green roof designers.
The morning was rich in exchanges, with a conference on nature in the city, followed by 3 workshops and a convivial lunch.
Each participant was able to take part in 2 workshops, led by the Hortibreiz and OdysséeLab teams.
In small groups of 8, participants were able to reflect on these 3 themes:
💧Water management
🌿 Urban cool islands
🪱 Biodiversity
The successful aim of this technical meeting was to provide a forum for the exchange of best practices and to forge links between professions and functions that rarely cross paths.
Fanny Maujean, landscape engineer, parks and gardens and landscapes director for the city of Angers and Angers Loire Métropole, presented us with Angers' Nature in city plan for 2021-2025.
The plan is bearing fruit, with Angers once again topping the latest list of France's green cities, for the 3rd time in a row, according to theObservatoire des villes vertes de France!
As green spaces have an undeniable beneficial impact on people, biodiversity and the economy, it's worth analyzing them at different scales: neighborhood, block and street. Mapping and understanding your city's green heritage is the basis for structuring a plan and allocating the necessary budgets:
- Area of green space per inhabitant, proximity, variety...
- Number and type of trees: remarkable signal trees, fruit trees... (by landscaped areas, mineralized areas, planted areas...)
During this highly participative conference, the emphasis was placed on 5 key areas that structure the action plan:
Priority 1: Strengthen Angers city' landscape identity
Challenges: develop, restore, reduce, compensate, demineralize, with the health of the population as the main objective.
Integrate more plant components into the Local Urbanism Plan. An example for Angers: removing 25% of school waterproofed grounds and doubling of their tree stock.
One problem: only 30% of the surface area is managed by the city (60% is privately owned) and 60% of this 30% is planted. We therefore need to do a great deal of work to raise awareness among the private sector, in order to improve the planting of the remaining 70% of private land.
Priority 2: Sustainable design and management
Challenges: adapting, building and managing urban ecosystems and biotopes.
Concept of a"sponge city"capable of absorbing water during rainy periods and releasing it during dry periods. Focus on an action: via a participatory budget of 1 million euros, private individuals can propose and implement specific actions. For example, the development of flower meadows to enhance biodiversity.
3: Knowing, preserving and developing the tree patrimony
Challenges: manage and develop a stocking level adapted to climate change and the preservation of biodiversity
Lots of discussion and questions on this central theme of trees in the city! To begin with, it's important to know your tree patrimony and how to manage it at the level of the canopy in the broadest sense, and not at the level of the individual tree.
We need to trust in nature's resilience and encourage species diversity.
Examples of actions in Angers:
- Tree financing (€50) for individuals with a garden.
- Miyawaki Forest: experimentation via the participatory budget.
- Creation of a 3-hectare urban forest following an intense phase of research into the suitability of the soil and plant species, and a study of the phyto-ecology of a nearby forest to replicate the same species... Following the soil study, trees and shrubs were planted with a forest hoe to protect and nourish the future tree. Without watering since their planting in 2019, the 1-year-old seedlings have had over 80% recovery: a success!
"The best of the fauna/flora lodges are the natural ones".
Area 4: Raising awareness and bringing people together
Challenges: raising awareness, mobilizing and involving staff.
Actions implemented :
- Launch of the https://www.angers-supernature.fr/sharing site: an interesting resource on plants.
- Programming of various events, such as the "Fleurissons Angers" competition, and the presence of vegetable gardens in local schools (in paloxes so that they can be moved around easily, especially in summer).
Priority 5: Enhance, monitor and evaluate
Challenges: publicize and measure the impact of actions and innovations
For example:
- Water management, crucial in summer, needs to be monitored via an "intelligent watering system" to reduce water consumption (-30%). Tensiometric probes can be used to optimize watering: it's essential to know where, when and how to apply water, so that it's as effective as possible for the plants.
- The creation of "digital twins" makes it possible to map urban heat and cool islands, to model the urban canopy... and thus to define and prioritize the actions to be taken.
The numerous labels awarded to the Angevin region are a source of pride and motivation for our agents on a daily basis: bravo!
Following Fanny Maujean's talk, each participant was able to take part in workshops led by the Hortibreiz and OdysséeLab teams on the themes of water management, cool islands and biodiversity. Here is the report on these participative workshops:
Workshop 💧Water management
The following effective practices were listed during the two workshops:
- Installation of green roof. For example, it insulates buildings, improves their energy performance, creates a refuge for biodiversity and combats urban heat islands.
- Resilient plantations
- Installation of flexible tanks. Beware: they take up space and cannot be washed from the inside.
- Use plastic or metal containers, but beware of the difficulty of replenishing water supplies at several points in the city.
Among the practices to be improved, the group discussed the following:
- Recover rainwater, then store it using water reservoirs to be adapted to existing structures (greenhouses, buildings + water lifting system). This technique reduces the amount of water entering the rainwater system during heavy rainfall events, thus avoiding overloading the system.
- Reuse of wastewater (swimming pool water, sewage, etc.). Legislation is currently very strict on the subject of reusing water (bacterial load), even for irrigation of sports fields, for example.
- Limiting and saving water use. By adapting and changing cultivation and planting practices, selected varieties, planting dates...
- Measure and program irrigation turns. Using sensors and automating the irrigation network (solenoid valves) makes it possible to quantify the quantity of water used and optimize the timing, quantity and frequency of watering according to the targeted plants and the current weather.
The aim of these best practices is to become as autonomous as possible when it comes to water management, so as to be able to water reasonably all year round - because without water, plants wither! In a context of more abundant but shorter rainy periods followed by longer, drier and hotter periods, it is essential to make water management part of a company's CSR policy.
Workshop 🌿 Urban cool islands
The following effective practices were listed during the two workshops:
- Cartography (GIS) for in-depth knowledge of your territory, tree patrimony, identification of heat islands...
- City beautification
- Planting of trees for cooling areas, sometimes fruit trees
- Increased use of green roofs and biodiversity areas
- Planting local, aesthetic plants
- Intermediary solutions: while waiting for the trees to grow and really play their cooling role, mobile solutions such as planters, potted trees and shading systems can be set up...
- Keeping pace with changing consumer habits.
In terms of practices to be improved and solutions to be found, discussions focused on :
- P lanning complicated (time, budget, interdepartmental links, etc.)
- Setting up a strategic plan between elected representatives and green space managers. One example is Lorient's "green reconquest" project.
- Training, understanding, willingness and ambition on the part of elected representatives
- Call in outside consultants if necessary
- Implementation costs
- Defining the city's strategy and the budget to be allocated to green spaces
- A need for decompartmentalizing departments (management, elected representatives...)
- Need for freedom of action, to be able to be a driving force
- Improving communication on best practices
- The following were cited: articles in the city's newspapers, billboards, consultation (to be properly framed) with residents, neighborhood meetings...
- Making teaching on the implementation of these cool islands and their constraints (plant growth time, plant diversity, soil desoiling, etc.).
- Installation of intermediate solutions: potted plants, shaded areas, etc.
- Water storage solutions: water bags, Ollas...
- Improved biodiversity in green roofs
- Need for greater substrate thickness, watering options to ensure plant survival and air cooling via evapotranspiration.
- Mineralization in demand in private homes, "Versailles syndrome" (domesticated plants, lawns cut short)
- Education, incentives, training in vegetable gardening, composting...
In conclusion, most cities already have trials in place. The creation of inter-departmental or inter-city working groups is of interest, but the involvement of the various players from the outset of the project is crucial to its success. Identifying heat islands calls for tools that can be shared between cities to make the implementation of cool islands more effective. The development of new forms of mobility (public transport, cycling, walking) should be encouraged in the creation of these spaces.
Reference was made to documentation available on the websites of the city of Angers, Lyon (especially rain trees), the city of Paris (on schoolyards), CEREMA...
Workshop 🪱 Biodiversity
The following effective practices were listed during the two workshops:
- Seedling trials (ESAT or city) for forest planting over the past 2 years
- Tolerance and acceptance of practices
- Awareness-raising and support from associations such as LPO
- Communication initiatives (Lorient mag, social networks, etc.)
- Enhancing agents' practices and know-how
- The creation of citizen movements (associations, heritage, etc.)
- Installation of nesting boxes for chickadees and bats, hedgehog shelters, natural pools for amphibians, plant diversity of interest to pollinators, eco-pasturing, late mowing...
- Setting up refuge areas
- Setting up trials (e.g. of ground cover plants over one and a half years)
- Manage mowing, pruning and trimming to promote biodiversity
- The elimination of plastic in mulching (PLA mulching, a biodegradable solution)
- Choice of species and varieties: adapting the range of varieties (drought, return of perennials, original cultivars, etc.) and implementing differentiated management (mowing, flowering).
- Eco-design of flowerbeds: maintenance, low water consumption, naturalizable bulbs, flowering mixes
- The end of phytosanitary treatments
- Installation of pollution and water quality sensors
Among the practices to be improved, discussions focused on :
- Planting vegetation at the foot of walls
- Developing soft pruning
- Back to pruning shears, fewer hedge trimmers
- Write a formalized strategy for each identified zone
- Define the notions of brown, green, blue and black grids (consultation between elected representatives, technical departments and residents).
- Evaluate, prioritize and implement actions in line with elected representatives' ambitions
- Train staff and raise their awareness (initiate change to other practices such as dividing perennials)
- Improving communication between cities
- Supporting experience-sharing
- Increase communication with residents (newspapers, neighborhood meetings, etc.).
A number of questions were raised during the workshop.
- The need to support elected representatives in explaining practices. For example, on the subject of mowing and the safety aspect for agents.
- How do you plant locally, but also how do you define "local"?
- How can we promote and manage green ditches?
In conclusion
The successful aim of this technical meeting was to provide a forum for the exchange of best practices and solutions to problems, and to forge links between towns, professions and functions that rarely cross paths.
It is this type of meeting and exchange that enables us, through our distributors like Hortibreiz and alongside their local authority and landscaping customers, to achieve the objectives we have set ourselves:
- Contribute to the challenges of urban transition through the use of plants and the creation of "cool islands " to meet climate and social challenges.
- To support local authorities and landscape gardeners in the design and management of green spaces by devising resilient solutions to the challenges of soil and water biodiversity.
- Bringing together local players in the plant sector to develop tomorrow's ideas.
