In Monaco, worldwide: Monumental trees as Urban Value for Climate & Social Mitigation.
- M Abti
- 1 day ago
- 5 min read
The Principality of Monaco preserves its rich botanical heritage through a dedicated urban green spaces, the Heritage Trees Course (Parcours des Arbres Patrimoniaux), combined with an active municipal engagement. Despite heavy urbanisation, the Principality protects exotic and native monumental specimens across its public gardens.
Established in 2013, by the Monaco City Hall (Mairie de Monaco), this curated path highlights rare and monumental trees originating from four continents housed within public grounds.
In recent years, large old (and younger) trees have drawn intense scientific interest for their irreplaceable role in both natural and urban landscapes. Their complex architecture—massive trunks, broad canopies, and deep root networks—allows them to deliver vital ecosystem services, notably: they filter pollutants, trap particulate matter, and regulate microclimates. Moreover, their sprawling root systems protect soil integrity and manage hydrological cycles. while acting as long-term carbon sinks, substantially helping mitigate urban heat island effects.
The ecological value criterion recognises trees that sustain other life forms by providing specific habitats for rare, specialised, or conservation-worthy flora and fauna. This value encompasses structural and functional elements, the so called dendromicrohabitats (tree-related microhabitats).
A recent Italian research study, entitled “Native and non-native monumental trees in cultural landscapes: a spatially heterogeneous source of biodiversity”*, has explored the characteristics and biodiversity role of the monumental tree community in the country. The research, conducted on the official Italian Ministry of Agriculture, Food Sovereignty and Forestry - MASAF database of November the 4th, 2024, checked 4,654 monumental entities distributed throughout Italy, offering an in-depth picture of their composition, distribution, and ecological relevance.
Monumental trees constitute a living heritage that spans eras, landscapes and cultures. In Italy they are present from sea level up to Alpine altitudes above 2,800 metres, and represent fundamental nodes of biodiversity and historical memory. The study shows that their distribution is by no means random: these green giants tend to concentrate in specific areas of the territory, forming real “hotspots” that often coincide with places with historical significance such as royal gardens, villas, monumental parks and cultural sites.
The species composition of this community reveals an interesting dynamic: native species are predominant in the not highly urbanised and wild national territory, while exotic species play a particularly significant role in urban areas.
This distinction highlights two complementary roles: on the one hand, native species, which embody the ecological legacy of the territory; on the other, exotic species, which tell the cultural and design history of the Italian landscape. A circumstance that occurs in many European Countries.
*Trees, Forests and People, Volume 22, December 2025, 101030 - Various Authors: Nicola Menon a, Giuseppe Brundu b c, D. Johan Kotze d, Nicola La Porta e f, Maria Cristina Monteverdi g, Yoan Paillet h, Paolo Semenzato, Tommaso Sitzia , Thomas Campagnaro
But you have to go to South America to find a prime example of a city that has massively invested in urban greenery to mitigate extreme climate effects. The 2.5-million-people metropolis of Medellín (Colombia) has implemented Green Corridors (Corredores Verdes) as a nature-based solution to climate change. Launched in 2016, the $16.3 million initiative planted 880,000 trees and 2.5 million smaller plants along 30 major roadways, waterways, and urban walkways, replacing heat-absorbing concrete and asphalt in the whole metro area, hosting up to 4 million inhabitants.
Green Corridors project successfully lowered average urban temperatures by 2°C, reduced harmful air pollution, while restoring local wildlife.
A more recent research study, named "Benefits of urban trees to people and their potential contribution to all the 17 sustainable development goals"* revealed that urban trees connect to all 17 Sustainable Development Goals, improving well-being, climate resilience, and city health. However, cities still fail to properly include green spaces in planning. Strategic planning must involve experts and focus on native trees that look good, fight urbanisation, and protect nature. This careful plan requires environmental experts and focuses on planting native trees to improve beauty, reduce city heat, support wildlife, and help people feel well.
Considering trees as economic, social, environmental drivers was clearly reiterated on the occasion of the final declaration of the G20 Leaders Summit held in Rome on October the 30th - 31 st, 2021 where the international delegations set the goal to plant 1 trillion trees on the Planet Earth by 2030.
“Acknowledging the urgency of combating land degradation and creating new carbon sinks, we share the aspirational goal to collectively plant 1 trillion trees, focusing on the most degraded ecosystems in the planet, and urge other countries to join forces with the G20 to reach this global goal by 2030, including through climate projects, with the involvement of the private sector and civil society” (G20 ROME LEADERS’ DECLARATION, 30th - 31st October 2021, Rome).
Managing monumental trees or young trees, after planting, is vital to ensure their survival, healthy growth, and long-term benefits. Key steps include regular watering, proper mulching, and routine structural growth-friendly pruning. It would be extremely useful to enhance greenery private-public policies and and encourage community engagement combining regulatory framework with environmentally-friendly best practices.
Every detail counts in the management of urban greenery. Even the choice of the most suitable tree species for urban environments also makes a difference with respect to air quality. Avoiding high Biogenic Volatile Organic Compound (BVOC) emissions from trees involves selecting low-emitting species, reducing plant stress, and diversifying urban forests. Restricting planting of major natural pollutant producers like oaks (Quercus), poplars (Populus), willows (Salix), and certain eucalyptus or pine species can can improve quality of life, especially in high-density urban or ozone-sensitive zones. At the same time, favouring low-BVOC (= Biogenic Volatile Organic Compound) emitting deciduous and evergreen trees such as specific maples (Acer), fruit trees, or other non-coniferous ornamental varieties is definitely the best choice in accordance to many local regional guidelines. Providing adequate irrigation is also crucial in order to prevent vulnerable trees from emitting terpene and isoprene (= natural gases produced by trees to protect their leaves from heat and insects). Controlling tree insect infestations is vital since physical harm and pest attacks trigger defensive volatile emissions.
** Trees, Forests and People, Volume 24, March 2026, 101198 - Various Authors: Willams Oliveira, Jéssica Luiza S. Silva, Marcelo Tabarelli, Ariadna V. Lopes Departamento de Botânica, Universidade Federal de Pernambuco, Pernambuco, Recife, Brazil.
Urban green areas are crucial city assets that drive climate resilience, biodiversity, and public health. From local parks and green roofs to community gardens, these natural features fight climate threats by lowering urban heat islands (UHI), enhancing storm water management and absorbing carbon as cities grow fast.
To maximise urban green spaces for climate change, city planners must focus on three core actions: smart design, proper upkeep, and fair access. This results in precise actions:
Setting rules requiring a set percentage of plant life in all new and old buildings;
Building rooftop gardens, vertical wall plants, and local parks into the city layout.
Providing steady money for watering, cleaning, and plant care to keep spaces safe and healthy.
Working with private groups to fund and manage green areas together.
Ensuring all neighborhoods, especially poor or neglected areas, getting equal access to safe outdoor nature spots. ***
✒️ Maurice Abbati
Strategic Communication Specialist, Editor in Chief, Journalist, Executive.
Lecturer and Author in English in the field of Environmental Communication to foster Circular and Blue Economy
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